Tally & Computer

Plotter

2009-07-27T09:02:00.001+05:30

A plotter is a vector graphics printing device to print graphical plots, that connects to a computer. There are two types of main plotters. Those are pen plotters and electrostatic plotters.

Pen plotters print by moving a pen across the surface of a piece of paper. This means that plotters are restricted to line art, rather than raster graphics as with other printers. Pen plotters can draw complex line art, including text, but do so very slowly because of the mechanical movement of the pens. Pen Plotters are incapable of creating a solid region of color; but can hatch an area by drawing a number of close, regular lines. When computer memory was very expensive, and processor power was very slow, this was often the fastest way to produce color high-resolution vector-based artwork, or very large drawings efficiently.

Traditionally, printers are primarily for printing text. This makes it fairly easy to control, simply sending the text to the printer is usually enough to generate a page of output. This is not the case of the line art on a plotter, where a number of printer control languages were created to send the more detailed commands like "lift pen from paper", "place pen on paper", or "draw a line from here to here". The two common ASCII-based plotter control languages are Hewlett-Packard's HPGL2 or Houston Instruments DMPL with commands such as "PA 3000, 2000; PD".

Programmers in FORTRAN or BASIC generally did not program these directly, but used software packages such as the Calcomp library, or device independent graphics packages such as Hewlett-Packard's AGL libraries or BASIC extensions or high end packages such as DISSPLA. These would establish scaling factors from world coordinates to device coordinates, and translating to the low level device commands. For example to plot X*X in HP 9830 BASIC, the program would be

**************************************

10 SCALE -1,1,1,1
20 FOR X =-1 to 1 STEP 0.1
30 PLOT X, X*X
40 NEXT X
50 PEN
60 END
**************************************

Early plotters (e.g. the Calcomp 565 of 1959) worked by placing the paper over a roller which moved the paper back and forth for X motion, while the pen moved back and forth on a single arm for Y motion. Another approach (e.g. Computervision's Interact I) involved attaching ball-point pens to drafting pantographs and driving the machines with motors controlled by the computer. This had the disadvantage of being somewhat slow to move, as well as requiring floor space equal to the size of the paper, but could double as a digitizer. A later change was the addition of an electrically controlled clamp to hold the pens, which allowed them to be changed and thus create multi-colored output.

Hewlett Packard and Tektronix created desk-sized flatbed plotters in the late 1970s. In the 1980s, the small and lightweight HP 7470 used an innovative "grit wheel" mechanism which moved only the paper. Modern desktop scanners use a somewhat similar arrangement. These smaller "home-use" plotters became popular for desktop business graphics, but their low speed meant they were not useful for general printing purposes, and another conventional printer would be required for those jobs. One category introduced by Hewlett Packard's MultiPlot for the HP 2647 was the "word chart" which used the plotter to draw large letters on a transparency. This was the forerunner of the modern Powerpoint chart. With the widespread availability of high-resolution inkjet and laser printers, inexpensive memory and computers fast enough to rasterize color images, pen plotters have all but disappeared.

Plotters were also used in the Create-A-Card kiosks that were available for a while in the greeting card area of supermarkets that used the HP 7475 6 pen plotter.

Plotters are used primarily in technical drawing and CAD applications, where they have the advantage of working on very large paper sizes while maintaining high resolution. Another use has been found by replacing the pen with a cutter, and in this form plotters can be found in many garment and sign shops.
If a plotter was commanded to use different colors it had to replace the pen and select the wanted color and/or width.
A niche application of plotters is in creating tactile images for visually handicapped people on special thermal cell paper.
Pen plotters have essentially become obsolete, and have been replaced by large-format inkjet printers and LED toner based printers. Such printers are often still known as plotters, even though they are raster devices rather than pen based plotters by the definition of this article. The newer plotters still understand vector languages such as HPGL2. This is because the language is an efficient way to describe how to draw the file using just text commands. A technical drawing in HPGL2 can be quite a bit smaller file than the same drawing in a pure raster form.

A pen plotter's speed is primarily limited by the type of pen used. The typical plotter pen uses a cellulose fiber rod inserted through a circular foam tube saturated with ink, with the end of the rod sharpened into a conical tip. As the pen moves across the paper surface, capillary wicking draws the ink from the foam, down the rod, and onto the paper. As the ink supply in the foam is depleted, the migration of ink to the tip begins to slow down, resulting in faint lines. Slowing the plotting speed will allow the lines drawn by a worn-out pen to remain dark, but the fading will continue until the foam is completely depleted. Also as the fiber tip pen is used, the fiber tip slowly wears away from rubbing against the media, wearing down the thin conical tip into a thicker smudged line.

Ball-point plotter pens with refillable clear plastic ink reservoirs are available. They do not have the fading or wear effects of fiber pens, but are generally more expensive and uncommon.

Information Society

2009-06-14T10:54:00.005+05:30

Meaning of Information Society

Information is now a vital resource in development activities of any society. Material Machine and Energy were considered as dominant factors which influence the societal development. The term Information Society can be expressed in different concepts. In a common parlance, it refers to a growing materially affluent service society where information rather than material, machine or energy is the dominant technology. It attempts towards a society characterized by increasing responsiveness towards individual human needs and towards presentation of ecological harmony and balance.

Characteristics of Information Society

The following can be described as some characteristics of an information society.

· Most of the members are engaged in productive pursuits that are knowledge intensive, knowledge generating and knowledge based.

· A communication network that freely circulates information so that this information is consistently, efficiently and effectively acted upon in making of choices.

Thus, in an information society the dominant factor for its development is information. Almost everything is decided on the basis of information, which has been provided by means of an information network. The decision pattern of the members of the society is now blended with the information he receives now, and the traditional concepts of values.

Theft of information

Theft is an offence under all laws. A person will be guilty of theft where he dishonestly appropriates the property of another with the intension of permanently depriving the owner of that property. Oxford dictionary defines theft as “dishonest appropriation of another’s property with intent-to deprive him or her of it permanently.” It is the felonious taking and carrying away of the property of another. Therefore, for theft, there should be a property and the intension to deprive the owner of permanently. The owner losses possession of the property and the thief acquires the possession.

Property means Right of Action for things that can be exchanged. Important types of property include real property (land), personal property (other physical possessions), and intellectual property (rights over artistic creations, inventions, etc.). A property is referred as something owned. It is defined as including ‘money and all other property, real or personal, including things in action and other incorporeal property. The first question with regard to the information theft is that, is it possible to lose the possession of information? With the special feature of information that it cannot be taken away from the mind of a person, it is very difficult to prove the condition of depriving the owner of property. Unlike the situation where, for example, a car is stolen, possession of the information will not be lost. So, a counter proposition can be that of the exclusive possession of knowledge or information. The second question is that whether information might be regarded as property for the purpose of the law of theft. To a certain extent this question is resolved and accepted that information may be considered as a property.

On the basis of the above prepositions, it can come to a conclusion that, information theft is possible. There have been a growing number of cases of information theft over the past few years. While more and more electronic security measures have been going up to protect people’s possessions and information, these new technologies have bugs and design flaws that are opening up whole new worlds for a technologically advanced criminal. Information thefts are done in different ways. Some of them are summarized below.

Credit Card Number Theft

This type of theft is done by creating a quick and dirty web site (which could be hosted for free, and anonymously) advertising some fictional product, and including a form for buying online. Instantly the perpetrators would have a list of credit card numbers linked with names and mailing addresses, ready to use for anything they want. People are using credit cards for more and more of their purchases as time go on. This is opening up a larger and larger arena for a credit card fraud. Credit cards are especially easy to use fraudulently, because they require no extra identification number to use. All that a thief needs is pure information-they don’t need the card, but just the number on the card. Recently, with people spending more on purchases transacted over the internet, credit card fraud is becoming easier. When a user visited to this web site and giving his credit card number, they will be stored by the site and would be used for anything they want to do.

ATM Spoofing

This is done by setting up a complete fake ATM machine inside a shopping centre. It looked and worked just like a real one, except that after giving it your card and typing in your PIN, it would refuse you service saying it was out of order. It then had a record of the card and PIN numbers of all the people who tried to use the machine. In one such reported case, the thieves then used legitimate ATM machines all over town to withdraw over $3,000 from these accounts.

Pin Capturing

This is done by hiding a video camera aimed at the keys on the ATM machine. After each successful PIN number identification that they recorded, the thief would go to check for a discarded receipt at the ATM. If he found one, had the card number and the PIN number.

Database Theft

There are large databases of customers’ information built up slowly and legally by mild-mannered, legitimate internet companies. For example, BMG Music Service lets customers give their credit card numbers when they sign up, so they don’t need to bother each time they make a purchase. There are thousands of users of this service, many of whom likely use this feature. The information of customers is hacked from these databases.

Cyberspace

The word ‘cyberspace’ was coined by William Gibson in his science fiction, Necromancer, published in 1984. It has subsequently become widely used as a means of representing the clear-or virtual-location within which electronic activities are undertaken. In an electronic communicating system, it is very difficult to locate the exact place of conversation occurred. For example, a contract is made by two parties through a telephone conversation. Each party’s words will be received by the other and there are rules regarding time and place of contract for the two ends ofthete1ephone call. Still, the overall conservation does not occur at either end of the connection. It virtually takes place anywhere in the telephone line between the parties of conversation. The imaginary location where the words of the parties meet in conversation is what is referred to as cyberspace. Thus, Cyber Space is a place where entry is not bound by geographic boundaries. Any person who lives in this Cyber Space is a part of the community referred to as the Netizen.

In the physical world today, there are requirements for documents to be in writing and for hand - written signatures. Due to the rapid development of electronic commerce, these requirements should be translated into the electronic realm. In order to get legal validity for this type of translation, there should be proper legislation by way of amendment of the existing ones. The advent of e-commerce and the use of the digital medium as an alternative to the physical have created some new legal issues where there are no clear answers.

The users of information technology must have trust in the security of information and communication and communications infrastructures, networks and systems. They should have trust in the confidentiality, integrity, and availability of data on them. They should also have trust in the ability to prove the origin and receipt of data. Since communication and transactions occurring over a faceless network, there is a need of reliable methods to authenticate a person’s identity and to ensure the integrity of the electronically transmitted documents.

Cyber law is a term used to describe the legal issues related to’ use of communications technology, particularly “cyberspace”, i.e. the Internet It is less a distinct field of law in the way that property or contract are, as it is an intersection of many legal fields, including intellectual property, privacy, freedom of expression, and jurisdiction. In essence, cyber law is an attempt to apply laws designed for the physical world to human activity on the Internet.

Jurisdiction and Sovereignty

One of the principles in case of laws of lands is with regard to the jurisdiction and sovereignty. A law can be enforced by an authority that has jurisdiction on the act or place and is sovereign. Issues of jurisdiction and sovereignty have quickly come to the fore in the era of the Internet. The Internet does not tend to make geographical and jurisdictional boundaries clear, but Internet users remain in physical jurisdictions and are subject to laws independent of their presence on the Internet. As such, a single transaction may involve the laws of at least three jurisdictions:

1. The laws of the state/nation in which the user resides

2. The laws of the state/nation that apply where the server hosting the transaction is located; and

3. The laws of the state/nation which apply to the person or business with whom the transaction takes place.

So a user in India conducting a transaction with another user in Britain through a server in USA could theoretically be subject to the laws of all three countries as they relate to the transaction at hand.

Jurisdiction is an aspect of state sovereignty and it refers to judicial, legislative and administrative competence. Although jurisdiction is an aspect of sovereignty, it is not coextensive with it. The laws of a nation may have extra-territorial impact extending the jurisdiction beyond the sovereign and territorial limits of that nation. This is particularly problematic as the medium of the Internet does not explicitly recognize sovereignty and territorial limitations. There is no uniform, international jurisdictional law of universal application, and such questions are generally a matter of conflict of laws, particularly private international law. For example, where the contents of a web site are legal in one country may be illegal in another. So, there should be a uniform jurisdictional code, otherwise, the legal practitioners are generally left with a conflict of law issue.

Another major problem of cyber law lies in whether to treat the Internet as if it were physical space (and thus subject to a given jurisdiction’s laws) or to act as if the Internet is a world unto itself (and therefore free of such restraints). There are strong arguments for and against of the above two perspective. John Perry Harlow proposes a new perspective known as Declaration of Cyber secession which is the perspective of absolute free to inhabit with no legal constraints. Though theoretically attractive, cyber secession initiatives have had little real impact on the Internet or the laws governing it. In practical terms, a user of the Internet is subject to the laws of the state or nation within which he or she goes online. Simply put, legal conduct in one nation may be decidedly illegal in another. In fact, even different standards concerning the burden of proof in a civil case can cause jurisdictional problems.

Contract Act under Cyber Law

In laws of contract, place of contract is important. The law of the place of contract is applicable to that contract. Similarly, the geographical location where conduct occurs is one of the major factors determining which country’s laws are applicable to the activities. The global network of communication actually made some problems with regard to the national boundaries. Hence the need for a new legal regime in cyberspace is argued. Although there is a clear role of some form of industry self regulation, this technique leave unrepresented the vast numbers of individual who deal with Internet Service Providers and the increasing number of organizations offering goods and services over the Internet Laws relating to contract, tort, defamation, evidence, broadcasting, media, data protection, intellectual property all have a role to play as do provisions of civil and criminal law. In fact, the inhabitants of cyberspace, depending upon the nature of their activities, may theoretically be subject to the jurisdiction of virtually all of the world’s legal systems.

Offer, Acceptance and legal enforceability are considered as most important factors of a contract. The growth of e-commerce on the Internet depends, to a large extent, on the confidence of traders in forming legally enforceable contracts online. The key activities associated with the formation of an enforceable contract do take part on the Internet, namely, the offer is communicated by the offeror, and acceptance is received by the offeror from the acceptor. An offer can be communicated orally or in writing; and in the e-commerce environment, it is through Internet. Electronic acceptance of the contract through e-mail, e- form is valid, in much the same way that a fax message is. The offeror can display terms and conditions as a legal notice, on his website. Visitors to the site, who choose to proceed further, even after reading the notice, may be construed to accept the conditions imposed by it. However timing of acceptance of the offer determines when the contract is formal. In this case, the e-mail of acceptance has to reach the offeror who may say that the contract will get formed only after its receipt.

In case of problems about jurisdiction, the problems are about the jurisdiction of the parties and jurisdiction of the website. These leads to the issues related to the identity of parties and the role ‘pf’ digital signatures on the Internet. Another problem is related to the establishment of competency of the parties to enter into a contract. All these issues and a few others are critical to the creation of an enforceable electronic contract. In Contract Act, when the offeree posts an acceptance, it becomes valid irrespective of whether it reached to the offeror or not. Some of the issues are dealt with the IT Act, 2000. It covers the attribution of electronic records, Acknowledgment of receipt, time and place of dispatch and receipt of electronic record.

Section 11 to 13 of the IT Act relate to the formation of an online contact between two parties that is solely mediated electronically. The originator of the electronic record sends it as a message which is deemed to have been received by the addressee, if he sends an acknowledgment, or conducts him in a manner so as to let the originator know that the message has been received by him. The two parties can agree on the formation of the contract depending on whether the acknowledgment of receipt of the electronic record by addressee has been stipulated as a condition by the originator. It has been mandated, and then the contract will be deemed to be formed only after receipt of the acknowledgment from the addressee. In the alternative case, if the originator does not receive any acknowledgment, or any indication that the addressee has received the electronic record sent by him, the originator can re-transmit the message stating that the time frame by which the acknowledgment should come, failing which the originator can treat the electronic record as thought it had never been sent.

The time of dispatch of the electronic record is deemed to be the time at which the electronic record enters a computer resource outside the control of the originator. Likewise, the time of receipt of an electronic record is taken to be the time it enters the computer resource designated by the addressee. These sections further clarify that the place of business of both the parties will be taken to be the place(s) where the electronic record will be deemed to have been originated, and received, respectively. This will be the case irrespective of where the computer resources of both parties may be located.

Contracts of Adhesion

Contract of adhesion is a contract you didn’t really bargain over in any way, but which was presented as more of a take-it-or-Leave-it offer. This type of contract is often offered by certain websites dealing with some products. For example, in case of a website providing news letter say, ABC.com, puts the following message at its web site: “You may obtain a one-year subscription to our newsletter ABC News for the special low price of Rs 150.00 for each monthly issue, simply by filling in your name and e-mail address on the form below and then clicking the ‘SUBSCRIBE’ button. By subscribing, you agree to the terms and conditions set forth in our Subscriber’s Contract; to read the Subscriber’s Contract, click on ‘CONTRACT TERMS’ below.” Now, suppose you fill in your name and e-mail address and click SUBSCRIBE, but you don’t actually take the time to look at, let alone read, the Subscriber’s Contract but at that moment you have a contract with ABC. There was an offer [to deliver the weekly newsletter to you], a specification of the behavior that the offeror deems to constitute acceptance of the offer [clicking on the SUBSCRIBE button], and consideration for the contract [the offeror will deliver the newsletter to you and you will pay Rs.150.00 per issue]. This “click wrap contract” is an example of what the law calls a “contract of adhesion.

Generally speaking, adhesion contracts are legally enforceable. Actually we enter into contracts like this all the time - e.g., when we buy something from the supermarket (without any chance to negotiate about the price of the item), or order some item from a restaurant, or park our car in a commercial lot, or undertake any of the other innumerable transactions where we agree, in effect, to pay the asking price for some good or service by virtue of some act of availing ourselves of the good or service.

But the question is: What are the terms of the contract? In particular, have you accepted the terms of the Subscriber’s Contract even if you haven’t read it? If you do something that is, prohibited by the Subscriber’s Contract, can ABC sue you for breach of contract? The basic principle of contract is the consensus ad idem. That is identity of mind. In Contract Acts there are provisions for the breach of contract. In those Acts also, the contract made in the above manner is interpreted as valid and breach of contract attracts remedy. In cyber-laws also the Contract of adhesion finds a place.

Securities Exchange Board Of India (SEBI)

2009-06-08T17:51:00.002+05:30

Introduction

The Government has set up the Securities and Exchange Board of India (SEBI) by a notification of Ministry of Finance issued on 12 April, 1988. SEBI is the apex body for the development and regulation of the stock market in India. After 4 years a separate legislation namely Securities and Exchange Board of India Act, 1992 has been enacted. Till then it was acted as an advisory body performing the following functions:

To collect information and advise the government on matters relating to stock and capital market.
Licensing and regulation of merchant bankers, mutual funds, etc.
To prepare the legal drafts for regulatory and development role of SEBI.
To perform any other functions as may be authorized to it by the Central Government.

By abolishing the office of Controller of Capital Issues (CCI) and by transferring some of the powers of Securities Contracts (Regulations) Act 1956 to SEBI, it was given statutory powers by an ordinance on 30th January. 1992. Thus, at present SEBI is armed with statutory power of regulating the primary market and supervising the functioning of stock exchanges in the country.SEBI’s Act 1992 provides for the establishment of a Board to protect interest of the investors in securities and promote the development of ital market and to regulate the security market and for matters connected with or incidental there to. The SEBI Act contains 7 chapters and 28 sections.

Objectives of SEBI

The primary objective of SEBI is to promote healthy and orderly growth -of the securities market and secure investor protection. The objectives of SEBI are as follows:

1.To protect the interest of investors, so that, there is a steady flow of savings into the capital market.
2.To regulate the securities market and ensure fair practices.
3.To promote efficient services by brokers, merchant bankers, and other intermediaries, so that, they become competitive and professional.

Functions of SEBI (Sec. 11)

The SEBI Act, 1992 has entrusted with two functions, they are

1.Regulatory functions and
2.Developmental functions

Chapter 4 of the Act deals with the Regulatory and Developmental functions of SEBI
a) Regulatory Functions: These include

1.Regulation of stock exchange and self regulatory organizations.
2.Registration and regulation of stock brokers, sub-brokers, Registrars to all issues, merchant bankers, underwriters, portfolio managers etc.
3.Registration and regulation of the working of collective investment schemes including mutual funds.
4.Prohibition of fraudulent and unfair trade practices relating to securities market.
5.Prohibition of insider trading
6.Regulating substantial acquisition of shares and takeover of companies.

b) Developmental Functions: These include

1.Promoting investor’s education
2.Training of intermediaries
3.Conducting research and publishing information useful to all market participants.
4.Promotion of fair practices
5.Promotion of self regulatory organizations

Powers of SEBI

In order to carry out its objectives, the following are the powers exercised by SEBI.

1.Power to call periodical returns from recognized stock exchanges.
2.Power to compel listing of securities by public companies.
3.Power to levy fees or other charges for carrying out the purposes of regulation.
4.Power to call information or explanation from recognized stock exchanges or their members.
5.Power to grant approval to bye-laws of recognized stock exchanges.
6.Power to control and regulate stock exchanges.
7.Power to direct enquiries to be made in relation to affairs of stock exchanges or their members.
8.Power to make or amend bye-laws of recognized stock exchanges.
9.Power to grant registration to market intermediaries.
10.Power to declare applicability of Section 17 of the Securities Contract (Regulation) Act 1956, in any State or area, to grant licenses to dealers in securities.

Powers delegated to SEBI under SCRA

The following are the powers delegated to SEBI under Securities Contract (Regulations) Act, 1956.

1.Power to call for periodical returns from stock exchange.
2.Grant approval to any recognized stock exchange to make bye-laws for the regulation or control of contracts.
3.Power to make or amend bye-laws of recognized stock exchanges.
4.Power to compel a public company to list its shares in any stock exchange.
5.icensing of dealers in securities in certain areas.
6.Power to appoint any person to make enquiries into the affairs of stock exchange.
7.Power to suspend business of any recognized stock exchange.
8.Power to prohibit contracts in certain cases.

Role of SEBI

The SEBI shall create a conductive atmosphere for the proper functioning of the capital market. The atmosphere includes the rules and regulations, trade practices, customs and relations among institutions, brokers, investors and companies. It shall have to get the trust of the investors in safeguarding their interest. This can be achieved by meeting the needs of persons connected with the securities market and establishing proper co-ordination among the three main groups - investors, corporate sector and intermediaries. SEBI shall create proper infrastructure, so that, the market automatically facilitate expansion and growth of business to middlemen like brokers, jobbers, merchant banks, mutual funds, commercial banks, etc. SEBI shall also create the framework for more open, orderly and un-prejudicial conduct in relation to takeover and mergers of corporate sector to ensure fair and equal treatment of all security holders. SEBI plays the dual role of regulation and development. The major roles of SEBI are discussed below:

1.It shall device laws with unified set of objectives, single administrative authority and an integral frame work to deal with all the aspects of the security market.
2.It shall also play an active role in interacting with institution of Chartered Accountants ·of India in upgrading and making more effective the accounting and auditing standards.
3.It shall introduce a system of two stage disclosure at the time of initial issue and make compulsory for the company to provide detailed information to all the stock exchange journals.
4.It will examine the feasibility of introducing a dealer’s network, by which securities can be bought or sold over the counter like in retail shop. This will smoothen liquidity and investment opportunities.
5.It shall work as an authoritative institution, to see that the intermediaries are financially sound and equipped with professional and competent manpower.
6.It will ensure that the rules are versatile and not rigid to provide automatic and self regulatory growth.

Organization of SEBI

The SEBI Act provides for the establishment of a Statutory Board consisting of six members. The chairman and two members are to be appointed by the Central Government, one member to be appointed by the Reserve Bank and two members having experience of securities market to be appointed by the Central Government.SEBI has divided the activities into four operational departments. They are primary market department, issue management and intermediary’s department, secondary market department and institutional department. Each department is headed by an Executive Director.

1.Primary Market Department: It deals with all policy matters and regulatory issues relating to primary market, market intermediaries and redressal of investor grievances.
2.Issue Management and Intermediaries Department: This department is concerned with vetting of offer documents and other things like registration, regulation and monitoring of issue related intermediaries.
3.Secondary Market Department: This department looks after all the policy and regulatory issues for the secondary market, administration of the major stock exchanges and other matters related to it.
4.Institutional Investment Department: This department is concerned with framing policy for foreign institutional investors, mutual funds and other matters like publications, membership in international organization etc.

In addition to the above, there are two other departments - Legal Department and Investigation Department.
SEBI has two advisory committees, one each for primary and secondary markets. The committees are constituted from among the market players, recognized investor associations and eminent persons associated with capital market. These committees are non-statutory committees.

SEBI and Central Government

The Central Government has power to issue directions to SEBI Board, supersede the Board, if necessary and to call for returns and reports as and when necessary. The Central Government has also power to give any guideline or to make regulations and rules for SEBI and its operations.

The activities of SEBI are financed by grants from Central Government, in addition to fees, charges etc. collected by SEBI. The fund called SEBI General Fund is set up, to which, all fees, charges and grants are credited. This fund is used to meet the expenses of the Board and to pay salary of staff and members of the body.

SEBI Guidelines
[Guidelines for Primary Market – Guidelines for Public Issue – Guidelines for Secondary Market - Guidelines for Foreign Institutional Investors - Guidelines on Bonus Issues – Guidelines on Right Issue – Guidelines on Underwriters]

1. Guidelines for Primary Market

New company

A new company is one which has not completed 12 months commercial production and doesn’t have audited results or where the promoters do not have a track record. Such companies will have to issue shares only at par.

A new company set up by existing companies with a five year track record of consistent profitability and a contribution of at least 50 % in the equity share of new company, it can issue its shares at premium i.e., it is free to price its issue.

Private and Closely held companies having a track record of consistent profitability for at least three years shall be permitted to price their issues freely. The issue price shall be fixed only after consulting with the lead managers to the issue.

Existing listed companies will be allowed to raise fresh capital by freely pricing expanded capital, provided the promoter’s contribution is 50% on first Rs.loo crores of issue, 40% on next Rs.2oo crores, 30% on next Rs.3oo crores and 15 % on balance issue amount.

In the case of composite issues (rights cum: public issue) by existing listed companies, differential pricing shall be allowed. However, justification for the price difference should be given in the offer document.Lock in period is five years for promoter’s contribution from the date of allotment or from the commencement of commercial production whichever is later. At present, the lock in period has been reduced to one year.

II. Guidelines for Public Issue

1.Abridged prospectus has to be attached with every application.
2.A company has to highlight the risk factors in the prospectus.
3.Objective of the issue and cost of project should be mentioned m the prospectus.
4.Company’s management, past history and present business of the firm should be highlighted in the prospectus.
5.Particulars regarding the company and other listed companies under the same management which made any capital issue during last three years are to be stated in the prospectus.
6.Justification for premium, incase premium is to be stated.
7.Subscription list for public issues should be kept open for a minimum of 3 days and a maximum of 40 working days.
8.The collection centers should be at least 30 which include all centers with stock exchanges.
9.Collection agents are not allowed to collect application money in cash.
10.The quantum of issue shall not exceed the amount specified in the prospectus. No retention of over subscription is permitted.
11.Minimum number of shares per application has been fixed at 500 shares of face value of Rs.loo/-
12.The allotments have to be made in multiples of tradable lot of 100 shares of Rs.1O each.
13.Issues by way of bonus, rights etc. to be made in appropriate lots to minimize odd lots.
14.If minimum subscription of 90% has not been received, the entire amount is to be refunded to investors within 120 days.
15.The capital issue should be fully paid up within 120 days.
16.Underwriting has been made mandatory.

III. Guidelines for Secondary Market

Stock Exchanges

1.Board of Directors of stock exchange has to be reconstituted so as to include non members, public representatives and government representatives to the extent of 50% of total number of members.
2.Capital adequacy norms have been laid down for members of various stock exchanges depending upon their turnover of trade and other factors.
3.Working hours for all stock exchanges have been fixed uniformly.
4.All the recognized stock exchange will have to inform about the transaction within 24 hours.
5.Guidelines have been issued for introducing the system of market making in less liquid scrips in a phased manner in all Stock Exchanges.

Brokers

1.Registration of brokers and sub-brokers is made compulsory.
2.In order to ensure professional qualification and financial solvency, capital adequacy norms for registration of brokers have been evolved.
3.Compulsory audit of broker’s book and filing of audit report with SEBI have been made mandatory.
4.For greater transparency and accountability in broker-client relationship, SEBI has made it mandatory for brokers to disclosetransaction price and brokerage separately in the contract notes issued to the clients.
5.No broker is allowed to underwrite more than 5% of public issues.

IV. Guidelines for Foreign Institutional Investors (FIIs)

1.Foreign Institutional Investors have been allowed to invest in all securities traded in primary and secondary markets.
2.There would be no restriction on the volume of investment for the purpose of entry of Foreign Institutional Investors.
3.The holding of Single Foreign Institutional Investor in a company will not exceed the ceiling of 5 % of the equity capital of the company.
4.Disinvestment will be allowed only through stock exchanges in India.
5.Foreign Institutional Investors have to pay a concessional tax rate of 10% on long term capital gain (to others - 20%) and 30% on short term capital gains. A tax rate of 20% on dividend and interest is prescribed.

V. Guidelines on Bonus Issues

The following are the SEBI guidelines relating to the issue of bonus shares.

1.There should be a provision in the Articles of Association of the company for the issue of bonus shares. If not, the company should pass a resolution for capitalization of reserves and should be recommended by the Board of Directors.
2.The bonus issue is made out of free reserves built out of genuine profits or share premiums collected in cash only.
3.Reserves created by revaluation of fixed assets are not ‘permitted to be capitalized.
4.The declaration of bonus issues in lieu of dividend is not to be made.
5.Bonus issues are not permitted, unless the existing partly paid shares are fully paid.
6.No bonus issues shall be permitted, if the company has defaulted in respect of payment of statutory dues to the employees.
7.No bonus issue can be made within 12 months of any public issue or right issue.
8.No bonus issue will be permitted if the company defaults in payment of principal or interest on fixed deposit or on debentures.
9.When a company announces the issue of bonus shares, it must be implemented within 6 months from the date of such proposal and shall not have the option of changing the decision.
10.The bonus issues after public or right issues shall not dilute the value or rights of the holders of fully or partly convertible debentures.

VI. Guidelines on Right Issues

1.Where composite issues are made by listed companies, they can be issued at different prices.
2.Gaps between the clearance dates of right issues and public issues should not exceed 30 days.
3.If right issues of listed companies exceed Rs.50 lakhs, issue should be managed by an authorized merchant banker.
4.Underwriting of right issues is not mandatory but as per SEBI Rules right issues can be underwritten.
5.No preferential allotment shall be made along with the right issues.
6.If the company doesn’t receive minimum subscription (90% of the issue amount) within 120 days from the date of opening issue, the entire subscription should be refunded within 128 days with interest @ 15 % p.a. for delay. .
7.The proposed right issue should not dilute the value or rights of fully or partly convertible debenture holders.
8.The issue should not exceed the quantum specified in the prospectus i.e., no part of over subscription is retained.
9.Within 45 days of closure of rights issue, a report in the prescribed form along with compliance report duly signed by the statutory auditor should be forwarded to SEBI.
10.All listed companies making rights issue shall issue an advertisement in at least two All India newspapers about the dispatch of letters of offer, opening date, closing date etc.

VII. SEBI Guidelines on Underwriters

1.No person can act as an underwriter, unless he holds certificate of registration granted by SEBI.
2.The certificate of registration is valid for 3 years from the date of issue.
3.The total underwriting obligations shouldn’t exceed 20 times of his net worth.
4.The underwriter should subscribe securities within 30 days of the receipt of the intimation from the company.
5.The underwriter should furnish within six months from the end of the financial year a copy of the Balance Sheet, Profit and Loss Account, the statement of capital adequacy requirement etc. as required by SEBI.
6.The books of accounts should be maintained for a period of 5 years.

Tally 9

2009-06-08T17:35:00.002+05:30

Tally 9 is the world’s first concurrent multi-lingual business accounting and inventory management software. Tally has been designed specifically for Indian business owners like you, who have always wanted to maintain accounts in an Indian language of your choice. Tally 9 is so technologically advanced that it can operate in almost all Indian languages concurrently! That means, you can maintain accounts in any Indian language, view it in another and print it in yet another language of your choice... at the same time!

Tally 9 empowers business owners to manage business smoothly. Designed keeping in mind the needs of the Indian businessman, it has several key additions in terms of functionality.

You can send separate documents to suppliers, business associates, customers etc., in their language, while maintaining accounts in your language. In effect, you can conveniently transact business across the length and breadth of India, and language will no longer be a barrier.

Freedom from dependence on accounting professionals is yet another clear benefit that Tally 9 enables… right from day one! You can let your accountant enter information in any Indian language that he is comfortable with and you can review it in your preferred language –at just the click of a button.
Backed by the heritage of incredible simplicity, Tally 9 takes one more significant step towards ensuring that concrete business advantages are realized from accounting on computers.

The advanced technology empowering Tally 9 allows you to:

What Does Tally 9 Offer?

Single-User Edition (Tally Silver)
Multi-User Edition (Tally Gold).
Best suited for small business at amazingly attractive prices!

Tally 9 - Best for Business Accounting

Complete Book-keeping
Books, Registers and Statements of Accounts
General Ledger
Out standings Management, including Credit Limits
Accounts Receivables and Accounts Payables
Flexible Voucher Numbering
Flexible Classification of Account Heads
Drill Down Display
Date based Reporting
Voucher and Cheque Printing
Columnar Reports
Bank Reconciliation

Tally 9 - Best For Business Financial Management

Funds Flows
Receivables Turnover (Payment Performance of
Debtors)
Branch Accounting
Flexible Period Accounting
Consolidation of Companies
Budgeting and Control
Cost Centers & Profit Centers, with Multiple Cost Categories
Variance Analysis
Ratio Analysis
Scenario Management including Reversing Journals and Optional Vouchers

Tally 9 - Best For Statutory Returns

VAT Statutory Returns
VAT Composition Returns
Service Tax
Tax Deducted at Source (TDS)
Fringe Benefit Tax (FBT)
Excise for Traders

What Makes Tally 9 The Best?

Simplicity in usage
Speed in navigation
Power of information management
Flexibility in adapting to your business
Concurrent multi-lingual capability
No codes for convenience
Real-time reporting
Online help for user friendly experience

Tally 9 - Best For Advanced Business Financial Management

Multiple Companies
Multi Currency Accounting
Multiple Financial Years
Comparison of Data using Multi-Columnar Reporting
Memo Vouchers
Post-dated Vouchers
User-defined Voucher Types
Sales and Purchase Extracts
Cash Flows
Daily Balances & Transaction Values
Interest Calculations
Percentage based Reporting

Tally 9 allows you to get the information you require in the format you need. Just create your format in any ODBC compliant software like MS-Word or MS-Excel, and pull data from Tally. To create any report you want. Like Audit Reports and Schedule VI forms. Or internal reports. You can even generate your export documentation by pulling data from Tally.

• MailTally Harness the power of the Internet! Tally 9 uses the SMTP protocol for e-mail. Now, e-mail invoices to your customer. Or your purchase order. In fact, e-mail any Tally report or document as easily as you print! Even reminder letters and statement of accounts need not be printed and posted. Simply e-mail them. It is not only postage cost that you save, you save on so much of your valuable time.

• E-Tally You can improve your company's efficiency by sharing information with your extended enterprise: your customers, your bankers, your business partners and other associates. Now publish all reports and documents from Tally 9 to a secure part of your website, using either FTP, HTTP or secure HTTP protocols, in HTML format. You can use this feature to inform customers the new price-range and stocks available for sale. Or publish reports that your CEO can access, while traveling, using any internet browser.

• XML Tally Tally 9 enables you to exchange information with non-Tally systems, using XML. You can now share data across locations, amongst business associates and partners, and make your workflow seamless. You can now collaborate with others and share information like never before.

• On-line Help Tally 9 has built in Context Sensitive Help. Press the Help button while in Tally, and it will bring up the relevant topic.

• "Scenario" management The new "Scenario" Management capability allows you to plan, as well as analyse your business performance, under varying assumptions. You can get different views of your accounts and inventory information by selectively including Optional Vouchers and/or Reversing Journals and Memos. Use this feature for forecasting and planning. Prepare reports including provisional figures without affecting actual accounts using reversing journals that automatically reverse. This is useful for reporting interim statements.

• Print Preview This facility helps you check printed report formats and layouts before actual printing takes place.

• Direct Access to the Internet Tally 9 allows you direct access to Web Browsing from within Tally.

• Tally 9 Cutting Edge technology

Tally 9 has achieved major technological breakthroughs to enable you to benefit from collaborative technology such as protocol support for HTTP, HTTPS, FTP, SMTP, ODBC, and Raw Sockets with data interchange formats like XML, HTML, SOAP, SDF and related formats, rule-based collaboration supporting export, upload and synchronization.

Keyboards

2009-06-06T11:14:00.006+05:30

Key boards- Type

In computing, a keyboard is an input device partially modeled after the typewriter keyboard which uses an arrangement of buttons, or keys which act as electronic switches. A keyboard typically has characters engraved or printed on the keys, and each press of a key typically corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence. While most keyboard keys produce letters, numbers or signs (characters), other keys or simultaneous key presses can produce actions or computer commands. In normal usage, the keyboard is used to type text or numbers into a word processor, text editor, or other program. In a modern computer the interpretation of key presses is generally left to the software. A computer keyboard distinguishes each physical key from every other and reports all key presses to the controlling software. Keyboards are also used for computer gaming, either with regular keyboards or by using special gaming keyboards which can expedite frequently used keystroke combination. A keyboard is also used give commands to the operating system of a computer, such as the Control-Alt-Delete combination, which brings up a task window or shuts down the machine.

The Dvorak Simplified Keyboard layout arranges keys so that frequently used keys are easiest to press, which reduces muscle fatigue when typing common English.

Types

Standard keyboards

Standard keyboards such as the 104-key Windows keyboards include alphabetic characters, punctuation symbols, numbers, and a variety of function keys. The internationally-common 102/105 key keyboards have a smaller 'left shift' key and an additional key with some more symbols between that and the letter to its right (usually Z or Y).

Keyboards with extra keys such as multimedia keyboards have special keys for accessing music, web, and other oft-used programs, a mute button, volume buttons or knob, and standby (sleep) button. Gaming keyboards have extra function keys which can be programmed with keystroke macros. For example, ctrl+shift+y could be a keystroke that is frequently used in a certain computer game. Shortcuts marked on color-coded keys are used for some software applications and for specialized for uses including word processing, video editing, graphic design, and audio editing.

Multimedia keyboards
have special keys for
accessing music,
websites, and
computer programs.

Smaller keyboards have been introduced for laptops, PDAs, cellphones, or users who have a limited workspace. The size of a standard keyboard is dictated by the practical consideration that the keys must be large enough to be easily pressed by fingers. To reduce the size of the keyboard, the numeric keyboard to the right of the alphabetic keyboard can be removed, or the size of the keys can be reduced, which makes it harder to enter text. Another way to reduce the size of the keyboard is to reduce the number of keys and use chording keyer, i.e. pressing several keys simultaneously. For example, the GKOS keyboard has been designed for small wireless devices. Other two-handed alternatives more akin to a game controller, such as the AlphaGrip, are also used as a way to input data and text. Another way to reduce the size of a keyboard is to use smaller buttons and pack them closer together. Such keyboards, often called a "thumbboard" (thumbing) are used in some personal digital assistants such as the Treo and BlackBerry and some Ultra-Mobile PCs such as the OQO.

Keyboards on laptops such as this
Sony VAIO usually have a shorter
travel distance for the keystroke and
a reduced set of keys.

Numeric keyboards contain only numbers, mathematical symbols for addition, subtraction, multiplication, and division, a decimal point, and several function keys (e.g. End, Delete, etc.). They are often used to facilitate data entry with smaller keyboard-equipped laptops or with smaller keyboards that do not have a numeric keypad.

Non-standard or special-use types

A keyset or chorded keyboard (also called a chord keyboard or chording keyboard) is a computer input device that allows the user to enter characters or commands formed by pressing several keys together, like playing a "chord" on a piano. The large number of combinations available from a small number of keys allows text or commands to be entered with one hand, leaving the other hand free to do something else. A secondary advantage is that it can be built into a device (such as a pocket-sized computer) that is too small to contain a normal sized keyboard. A chorded keyboard designed to be used while held in the hand is called a keyer.

The Microwriter MW4 (circa 1980) uses
a chording keyboard in which several key
presses are needed for each letter.

Virtual keyboards, such as the I-Tech Virtual Laser Keyboard, project an image of a full-size keyboard onto a surface. Sensors in the projection unit identify which key is being "pressed" and relay the signals to a computer or personal digital assistant. There is also a virtual keyboard, the On-Screen Keyboard, for use on Windows.

Touchscreens such as with the iPhone and the OLPC laptop can be used as a keyboard. (The OLPC initiative's second computer will be effectively two tablet touchscreens hinged together like a book. It can be used as a convertible tablet PC where the keyboard is one half-screen (one side of the book) which turns into a touchscreen virtual keyboard.)

Foldable keyboards are made of soft plastic which can be rolled or folded over for travel. When in use, the keyboard can conform to uneven surfaces, and it is more resistant to liquids than a standard keyboard.

How To Invoice

2009-06-06T11:10:00.002+05:30

HOW TO INVOICE:

Once you've sold the product or provided the service, its invoice time. An invoice not only shows the customer or client how much money is due but provides tax information. Both you and your customers need to be able to track how much GST (Goods and Services Tax.) and/or PST (Provincial Sales Tax/Retail Sales Tax) is paid or owed, for instance. Because invoices are such an important part of your business records, it's important to get them right.

WHAT HAS TO BE ON THE INVOICE?

There are certain pieces of information that have to be on your invoices. Your invoice must include:

* Your business name
* The date of the invoice
* Your Business Number
* The purchaser's name
* A brief description of the goods or services performed
* The total amount paid or payable
* The terms of payment
* an indication of items subject to GST at 6% or HST at 14%, or that the items are exempt, and either the total amount of GST/HST charged, or a statement that the GST/HST is included and the total rate of tax
* if applicable, an indication of items subject to PST (also known as RST) at the provincial rate, or that the items are exempt, and either the total amount of PST charged, or a statement that the PST is included and the total rate of tax.So what does a complete invoice look like? Here's an invoice sample that you can use as an invoice template.

_______________________________________________________
Sample Invoice
**************
Cypress Technologies
Suite 7, 77 Marwood Place
Crestwood, B.C., V6T 7Q7
1-888-888-888

Sarah's Computer Bin
8424 Business Plaza
Vancouver, B.C., V9W 2T2

Att'n: Sarah Norgaard

INVOICE FOR:

1 HP OfficeJet Inkjet Color Printer $583.97
GST $35.03
PST$ 43.80

TOTAL PAYABLE: $662.80

GST Registration No. 888888888

Invoice No. 754

Date of Invoice: Month Day, 2006

To be paid within 30 days of invoice date.
___________________________________________________________

To use this sample invoice, just copy it into Word or some other word processor, and substitute your relevant data, using your own customized business letterhead, if you like, and formatting as you desire. This is a product invoice from one business to another in the same province; if you provide services, rather than sell products, you may wish to use the subheading "Description of the Work Performed" along with the Invoice for heading.

Note the statement at the bottom of the invoice, saying that the invoice amount is due within 30 days. You'll often see invoices that say, "Payable upon Receipt", but that's just asking for trouble, because you don't necessarily know when your customer or client is seeing the invoice - even if you've emailed it. Using a specific terms statement like the one on this invoice gives your customer a due date, and helps you to avoid collection problems.

Invoices are even easier to do if you use accounting software. Accounting software designed for small businesses can not only be used as POS (Point of Sale) systems and print out invoices on the spot, but make it easier to calculate and keep track of taxes, such as the GST.

INVOICE

2009-06-06T11:05:00.002+05:30

INVOICE:

An invoice is essentially a detailed bill left by vendors and outside suppliers for goods or services rendered to a company. A typical invoice might list the quantity of each item, prices, billable hours, service description and a contact address for payment. While some expenses may be paid out of a general fund or petty cash account, an invoice is usually paid through an accounts payable department by the posted due date.

An invoice is a legal document which can be used as evidence of an incurred debt. The recipient of the goods or services can challenge the legitimacy of individual charges, but the invoice itself is considered a bonafide debt. Sometimes a vendor or serviceman cannot collect on a bill immediately, so their company will send an invoice at a later date for payment. The actual daily expense of a service may be so low that a company will simply wait for a larger invoice to cover all of the costs at once. Vending machine attendants and bottled water providers may only send one invoice a month instead of billing the company a few dollars a day for supplies.

Not all invoices are bills of sale, however. A manufacturer may send out a 'shipping invoice', which details all of the parts and accessories included in a particular order. This shipping invoice should be compared to the actual parts received by the store or customer. Car dealers also receive an invoice from the factory which details the actual price of the basic vehicle and any optional equipment installed. The dealer may offer a discount to the customer which seems to fall below the invoice price.

The use of an invoice as evidence of a legitimate debt can sometimes be abused. Unscrupulous companies may generate false invoices to account for missing funds or to inflate sales numbers to stockholders. An invoice is only enforceable and legal if corroborative evidence (inventory, duplicate bills, etc.) proves the goods actually exist or the service was actually performed. Companies and individuals do have the right to challenge suspicious invoices in a court of law.

Some companies who use invoices frequently will design their own forms, but generic invoice forms can be ordered at office supply stores. There are also computer programs available which can generate specialized invoice forms through the use of templates. A professional invoice should contain detailed information on the goods or services, clear and accurate prices and current contact information for any billing questions a client may have.

Trackball

2009-06-02T20:03:00.000+05:30

A trackball is a pointing device consisting of a ball housed in a socket containing sensors to detect rotation of the ball about two axes—like an upside-down mouse with an exposed protruding ball. The user rolls the ball with the thumb, fingers, or the palm of the hand to move a cursor. Large tracker balls are common on CAD workstations for easy precision. Before the advent of the touchpad, small trackballs were common on portable computers, where there may be no desk space on which to run a mouse. Some small thumbballs clip onto the side of the keyboard and have integral buttons with the same function as mouse buttons.

The trackball was invented by Tom Cranston and Fred Longstaff as part of the Royal Canadian Navy's DATAR system in 1952, eleven years before the mouse was invented. This first trackball used a Canadian five-pin bowling ball.

When mice still used a mechanical design (with slotted 'chopper' wheels interrupting a beam of light to measure rotation), trackballs had the advantage of being in contact with the user's hand, which is generally cleaner than the desk or mouse-pad and doesn't drag lint into the chopper wheels. The late 1990s advent of scroll wheels, and the replacement of mouse balls by direct optical tracking, put trackballs at a disadvantage and forced them to retreat into niches where their distinctive merits remained important. Most trackballs now have direct optical tracking which follows dots on the ball. Some mice, in place of a scroll wheel, acquired a small trackball between the buttons, useful in maps and other circumstances calling for scrolling in two dimensions.

Special Applications

Large tracker balls are sometimes seen on computerized special-purpose workstations, such as the radar consoles in an air-traffic control room or sonar equipment on a ship or submarine. Modern installations of such equipment may use mice instead, since most people now already know how to use one. However, military mobile anti-aircraft radars and submarine sonars tend to continue using trackballs, since they can be made more durable and more fit for fast emergency use. Large and well made ones allow easier high precision work, for which reason they are still used in these applications (where they are often called "tracker balls") and in computer-aided design.

Trackballs have appeared in computer and video games, particularly early arcade games (see a List of trackball arcade games) notably Atari's Centipede and Missile Command. "Football", by Atari, was the first arcade game to use a trackball, released in 1978 - though Atari spells it "trak-ball". Console trackballs, once common in the early 1980s, are now fairly uncommon: the Atari 2600 and 5200 consoles had one as an optional peripheral, with a joystick as standard. The Bandai Atmark, a Japanese console introduced in 1995 had a trackball as standard for its game-pad. Trackballs are also preferred by many so-called professional gamers, who value their consistency highly. A trackball requires no mouse-pad and enables the player to aim swiftly (in first person shooters). Trackballs remain in use in pub golf machines (such as Golden Tee) to simulate swinging the club.

Computer gamers have been able to successfully use trackballs in most modern computer games, including FPS, RPG, and RTS genres, with any slight loss of speed compensated for with an increase in precision. Many trackball gamers are competent at "throwing" their cursor rapidly across the screen, by spinning the trackball, enabling (with practice) much faster motion than can be achieved with a mouse and arm motion. However, many gamers are deterred by the time it takes to 'get used to' the different style of hand control that a trackball requires. Trackballs have also been regarded as excellent complements to analog joysticks, as pioneered by the Assassin 3D 1996 trackball with joystick pass-through capability. This combination provides for two-hand aiming and a high accuracy and consistency replacement for the traditional mouse and keyboard combo generally used on first-person shooter games. Many such games natively support joysticks and analog player movement, like Valve's Half-Life and id Software's Quake series.

Trackballs are provided as the pointing device in some public internet access terminals. Unlike a mouse, a trackball can easily be built into a console, and cannot be ripped away or easily vandalised. Two examples are the Internet browsing consoles provided in some UK McDonalds outlets, and the BT Broadband Internet public phone boxes.

Because trackballs for personal computers are stationary, they may require less space for operation than a mouse, and may simplify use in confined or cluttered areas such as a small desk.

The world's first trackball working on the invented by Tom Cranston, Fred Longstaff and Kenyon Taylor Royal Canadian Navy's DATAR project in 1952. It used a standard Canadian five-pin bowling ball.

MODEM

2009-05-27T16:58:00.000+05:30

MODEM

Modem (from modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Modems can be used over any means of transmitting analog signals, from driven diodes to radio.

The most familiar example is a voice band modem that turns the digital 1s and 0s of a personal computer into sounds that can be transmitted over the telephone lines of Plain Old Telephone Systems (POTS), and once received on the other side, converts those 1s and 0s back into a form used by a USB, Ethernet, serial, or network connection. Modems are generally classified by the amount of data they can send in a given time, normally measured in bits per second, or "bps". They can also be classified by Baud, the number of times the modem changes its signal state per second.

Baud is not the modem's speed in bit/s, but in symbols/s. The baud rate varies, depending on the modulation technique used. Original Bell 103 modems used a modulation technique that saw a change in state 300 times per second. They transmitted 1 bit for every baud, and so a 300 bit/s modem was also a 300-baud modem. However, casual computerate's confused the two. A 300 bit/s modem is the only modem whose bit rate matches the baud rate. A 2400 bit/s modem changes state 600 times per second, but due to the fact that it transmits 4 bits for each baud, 2400 bits are transmitted by 600 baud, or changes in states.

Faster modems are used by Internet users every day, notably cable modems and ADSL modems. In telecommunications, "radio modems" transmit repeating frames of data at very high data rates over microwave radio links. Some microwave modems transmit more than a hundred million bits per second. Optical modems transmit data over optical fibers. Most intercontinental data links now use optical modems transmitting over undersea optical fibers. Optical modems routinely have data rates in excess of a billion (1x109) bits per second. One kilobit per second (kbit/s or kb/s or kbps) as used in this article means 1000 bits per second and not 1024 bits per second. For example, a 56k modem can transfer data at up to 56,000 bits (7kB) per second over the phone line.

History

News wire services in the year of 1920s used multiplex equipment that met the definition, but the modem function was incidental to the multiplexing function, so they are not commonly included in the history of modems. George Stibitz connected a New Hampshire teletype to a computer in New York City by phone lines in 1940. Modems in the United States were part of the SAGE air-defense system in the 1950s, connecting terminals at various airbases, radar sites, and command-and-control centers to the SAGE director centers scattered around the U.S. and Canada. SAGE ran on dedicated communications lines, but the devices at each end were otherwise similar in concept to today's modems. A few years later, a chance meeting between the CEO of American Airlines and a regional manager of IBM led to development of a "mini-SAGE" as an automated airline ticketing system. The terminals were at ticketing offices, tied to a central computer that managed availability and scheduling. The system, known as SABRE, is the ancestor of today's Sabre system.

AT&T monopoly in the United States
For many years, AT&T maintained a monopoly in the United States on the use of its phone lines, allowing only AT&T-supplied devices to be attached to its network. For the growing group of computer users, AT&T introduced two digital sub-sets in 1958. One is the wideband device shown in the picture to the right. The other was a low-speed modem, which ran at 200 baud.

Legacy modem for leased line operation.

In the summer of 1960, the name Data-Phone was introduced to replace the earlier term digital subset. The 202 Data-Phone was a half-duplex asynchronous service that was marketed extensively in late 1960. In 1962, the 201A and 201B Data-Phones were introduced. They were synchronous modems using two-bit-per-baud phase-shift keying (PSK). The 201A operated half-duplex at 2000 bit/s over normal phone lines, while the 201B provided full duplex 2400 bit/s service on four-wire leased lines, the send and receive channels running on their own set of two wires each.

The famous 103A was also introduced in 1962. It provided full-duplex service at up to 300 baud over normal phone lines. Frequency-shift keying (FSK) was used with the call originator transmitting at 1070 or 1270 Hz and the answering modem transmitting at 2025 or 2225 Hz. The readily available 103A2 gave an important boost to the use of remote low-speed terminals such as the KSR33, the ASR33, and the IBM 2741. AT&T reduced modem costs by introducing the originate-only 113D and the answer-only 113B/C modems.

The Carterfone decision

The Novation CAT acoustically coupled modem Before 1968.

AT&T maintained a monopoly on what devices could be electrically connected to its phone lines. This led to a market for 103A-compatible modems that were mechanicallyacoustically coupled modems. Particularly common models from the 1970s were the Novation CAT (shown in the image) and the Anderson-Jacobson, spun off from an in-house project at the Lawrence Livermore National Laboratory. connected to the phone, through the handset, known as Hush-a-Phone v. FCC was a seminal ruling in United States telecommunications law decided by the DC Circuit Court of Appeals on November 8, 1956. The District Court found that it was within the FCC's authority to regulate the terms of use of AT&T's equipment. Subsequently, the FCC examiner found that as long as the device was not physically attached it would not threaten to degenerate the system. Later, in the Carterfone decision, the FCC passed a rule setting stringent AT&T-designed tests for electronically coupling a device to the phone lines. AT&T made these tests complex and expensive, so acoustically coupled modems remained common into the early 1980s.

In December 1972, Vadic introduced the VA3400. This device was remarkable because it provided full duplex operation at 1200 bit/s over the dial network, using methods similar to those of the 103A in that it used different frequency bands for transmit and receive. In November 1976, AT&T introduced the 212A modem to compete with Vadic. It was similar in design to Vadic's model, but used the lower frequency set for transmission. It was also possible to use the 212A with a 103A modem at 300 bit/s. According to Vadic, the change in frequency assignments made the 212 intentionally incompatible with acoustic coupling, thereby locking out many potential modem manufacturers. In 1977, Vadic responded with the VA3467 triple modem, an answer-only modem sold to computer center operators that supported Vadic's 1200-bit/s mode, AT&T's 212A mode, and 103A operation.

The Smart modem and the rise of BBSes

US Robotics Sportster 14,400 Fax modem (1994)

The next major advance in modems was the Smartmodem, introduced in 1981 by Hayes Communications. The Smartmodem was an otherwise standard 103A 300-bit/s modem, but was attached to a small controller that let the computer send commands to it and enable it to operate the phone line. The command set included instructions for picking up and hanging up the phone, dialing numbers, and answering calls. The basic Hayes command set remains the basis for computer control of most modern modems.

Prior to the Hayes Smartmodem, modems almost universally required a two-step process to activate a connection: first, the user had to manually dial the remote number on a standard phone handset, and then secondly, plug the handset into an acoustic coupler. Hardware add-ons, known simply as dialers, were used in special circumstances, and generally operated by emulating someone dialing a handset.

With the Smartmodem, the computer could dial the phone directly by sending the modem a command, thus eliminating the need for an associated phone for dialing and the need for an acoustic coupler. The Smartmodem instead plugged directly into the phone line. This greatly simplified setup and operation. Terminal programs that maintained lists of phone numbers and sent the dialing commands became common.

The Smartmodem and its clones also aided the spread of bulletin board systems (BBSs). Modems had previously been typically either the call-only, acoustically coupled models used on the client side, or the much more expensive, answer-only models used on the server side. The Smartmodem could operate in either mode depending on the commands sent from the computer. There was now a low-cost server-side modem on the market, and the BBSs flourished.

Softmodem (dumb modem)

Apple's GeoPort modems from the second half of the 1990s were similar. Although a clever idea in theory, enabling the creation of more-powerful telephony applications, in practice the only programs created were simple answering-machine and fax software, hardly more advanced than their physical-world counterparts, and certainly more error-prone and cumbersome. The software was finicky and ate up significant processor time, and no longer functions in current operating system versions. Almost all modern modems also do double-duty as a fax machine as well. Digital faxes, introduced in the 1980s, are simply a particular image format sent over a high-speed (commonly 14.4 kbit/s) modem. Software running on the host computer can convert any image into fax-format, which can then be sent using the modem. Such software was at one time an add-on, but since has become largely universal.

A PCI Winmodem / Softmodem
(on the left) next to a traditional
ISA modem (on the right).
Notice the less complex circuitry
of the modem on the left.

A Winmodem or Softmodem is a stripped-down modem that replaces tasks traditionally handled in hardware with software. In this case the modem is a simple digital signal processor designed to create sounds, or voltage variations, on the telephone line. Softmodems are cheaper than traditional modems, since they have fewer hardware components. One downside is that the software generating the modem tones is not simple, and the performance of the computer as a whole often suffers when it is being used. For online gaming this can be a real concern. Another problem is lack of portability such that other OSes (such as Linux) may not have an equivalent driver to operate the modem. A Winmodem might not work with a later version of Microsoft Windows, if its driver turns out to be incompatible with that later version of the operating system.

Narrow band/phone-line dial up modems

28.8 kbit/s serial port modem from Motorola

A standard modem of today contains two functional parts: an analog section for generating the signals and operating the phone, and a digital section for setup and control. This functionality is actually incorporated into a single chip, but the division remains in theory. In operation the modem can be in one of two "modes", data mode in which data is sent to and from the computer over the phone lines, and command mode in which the modem listens to the data from the computer for commands, and carries them out. A typical session consists of powering up the modem (often inside the computer itself) which automatically assumes command mode, then sending it the command for dialing a number. After the connection is established to the remote modem, the modem automatically goes into data mode, and the user can send and receive data. When the user is finished, the escape sequence, "+++" followed by a pause of about a second, is sent to the modem to return it to command mode, and the command ATH to hang up the phone is sent.

The commands themselves are typically from the Hayes command set, although that term is somewhat misleading. The original Hayes commands were useful for 300 bit/s operation only, and then extended for their 1200 bit/s modems. Faster speeds required new commands, leading to a proliferation of command sets in the early 1990s. Things became considerably more standardized in the second half of the 1990s, when most modems were built from one of a very small number of "chip sets". We call this the Hayes command set even today, although it has three or four times the numbers of commands as the actual standard.

Increasing speeds (V.21 V.22 V.22bis)

A 2400 bit/s modem for a laptop.

The 300 bit/s modems used frequency-shift keying to send data. In this system the stream of 1s and 0s in computer data is translated into sounds which can be easily sent on the phone lines. In the Bell 103 system the originating modem sends 0s by playing a 1070 Hz tone, and 1s at 1270 Hz, with the answering modem putting its 0s on 2025 Hz and 1s on 2225 Hz. These frequencies were chosen carefully, they are in the range that suffer minimum distortion on the phone system, and also are not harmonics of each other.

In the 1200 bit/s and faster systems, phase-shift keying was used. In this system the two tones for any one side of the connection are sent at the similar frequencies as in the 300 bit/s systems, but slightly out of phase. By comparing the phase of the two signals, 1s and 0s could be pulled back out, for instance if the signals were 90 degrees out of phase, this represented two digits, "1,0", at 180 degrees it was "1,1". In this way each cycle of the signal represents two digits instead of one. 1200 bit/s modems were, in effect, 600 symbols per second modems (600 baud modems) with 2 bits per symbol.

Voice band modems generally remained at 300 and 1200 bit/s (V.21 and V.22) into the mid 1980s. A V.22bis 2400-bit/s system similar in concept to the 1200-bit/s Bell 212 signalling was introduced in the U.S., and a slightly different one in Europe. By the late 1980s, most modems could support all of these standards and 2400-bit/s operation was becoming common.

Increasing speeds (one-way proprietary standards)

Many other standards were also introduced for special purposes, commonly using a high-speed channel for receiving, and a lower-speed channel for sending. One typical example was used in the French Minitel system, in which the user's terminals spent the majority of their time receiving information. The modem in the Minitel terminal thus operated at 1200 bit/s for reception, and 75 bit/s for sending commands back to the servers.

Three U.S. companies became famous for high-speed versions of the same concept. TelebitTrailblazer modem in 1984, which used a large number of 36 bit/s channels to send data one-way at rates up to 18,400 bit/s. A single additional channel in the reverse direction allowed the two modems to communicate how much data was waiting at either end of the link, and the modems could change direction on the fly. The Trailblazer modems also supported a feature that allowed them to "spoof" the UUCP "g" protocol, commonly used on Unix systems to send e-mail, and thereby speed UUCP up by a tremendous amount. Trailblazers thus became extremely common on Unix systems, and maintained their dominance in this market well into the 1990s.

Introduced its U.S. Robotics (USR) introduced a similar system, known as HST, although this supplied only 9600 bit/s (in early versions at least) and provided for a larger backchannel. Rather than offer spoofing, USR instead created a large market among Fidonet users by offering its modems to BBS sysops at a much lower price, resulting in sales to end users who wanted faster file transfers. Hayes was forced to compete, and introduced its own 9600-bit/s standard, Express 96 (also known as "Ping-Pong"), which was generally similar to Telebit's PEP. Hayes, however, offered neither protocol spoofing nor sysop discounts, and its high-speed modems remained rare.

4800 and 9600 (V.27ter, V.32)
Echo cancellation was the next major advance in modem design. Local telephone lines use the same wires to send and receive, which results in a small amount of the outgoing signal bouncing back. This signal can confuse the modem. Is the signal it is "hearing" a data transmission from the remote modem, or its own transmission bouncing back? This was why earlier modems split the signal frequencies into answer and originate; each modem simply didn't listen to its own transmitting frequencies. Even with improvements to the phone system allowing higher speeds, this splitting of available phone signal bandwidth still imposed a half-speed limit on modems.

Echo cancellation got around this problem. Measuring the echo delays and magnitudes allowed the modem to tell if the received signal was from itself or the remote modem, and create an equal and opposite signal to cancel its own. Modems were then able to send at "full speed" in both directions at the same time, leading to the development of 4800 and 9600 bit/s modems.

Increases in speed have used increasingly complicated communications theory. 1200 and 2400 bit/s modems used the phase shift key (PSK) concept. This could transmit two or three bits per symbol. The next major advance encoded four bits into a combination of amplitude and phase, known as Quadrature Amplitude Modulation (QAM). Best visualized as a constellation diagram, the bits are mapped onto points on a graph with the x (real) and y (quadrature) coordinates transmitted over a single carrier.

The new V.27ter and V.32 standards were able to transmit 4 bits per symbol, at a rate of 1200 or 2400 baud, giving an effective bit rate of 4800 or 9600 bits per second. The carrier frequency was 1650 Hz. For many years, most engineers considered this rate to be the limit of data communications over telephone networks.

Error correction and compression

Operations at these speeds pushed the limits of the phone lines, resulting in high error rates. This led to the introduction of error-correction systems built into the modems, made most famous with Microcom's MNP systems. A string of MNP standards came out in the 1980s, each increasing the effective data rate by minimizing overhead, from about 75% theoretical maximum in MNP 1, to 95% in MNP 4. The new method called MNP 5 took this a step further, adding data compression to the system, thereby increasing the data rate above the modem's rating. Generally the user could expect an MNP5 modem to transfer at about 130% the normal data rate of the modem. MNP was later "opened" and became popular on a series of 2400-bit/s modems, and ultimately led to the development of V.42 and V.42bis ITU standards. V.42 and V.42bis were non-compatible with MNP but were similar in concept: Error correction and compression.

Another common feature of these high-speed modems was the concept of fallback, allowing them to talk to less-capable modems. During the call initiation the modem would play a series of signals into the line and wait for the remote modem to "answer" them. They would start at high speeds and progressively get slower and slower until they heard an answer. Thus, two USR modems would be able to connect at 9600 bit/s, but, when a user with a 2400-bit/s modem called in, the USR would "fall back" to the common 2400-bit/s speed. This would also happen if a V.32 modem and a HST modem were connected. Because they used a different standard at 9600 bit/s, they would fall back to their highest commonly supported standard at 2400 bit/s. The same applies to V.32bis and 14400 bit/s HST modem, which would still be able to communicate with each other at only 2400 bit/s.

Breaking the 9.6k barrier

In 1980 Gottfried Ungerboeck from IBM Zurich Research Laboratory applied powerful channel coding techniques to search for new ways to increase the speed of modems. His results were astonishing but only conveyed to a few colleagues. Finally in 1982, he agreed to publish what is now a landmark paper in the theory of information coding. By applying powerful parity check coding to the bits in each symbol, and mapping the encoded bits into a two dimensional "diamond pattern", Ungerboeck showed that it was possible to increase the speed by a factor of two with the same error rate. The new technique was called "mapping by set partitions" (now known as trellis modulation). This new view was an extension of the "penny packing" problem[clarify] and the related and more general problem of how to pack points into an N-dimension sphere such that they are far away from their neighbors. The greater two bit sequences are from one another, the easier it is to correct minor errors.

The industry was galvanized into new research and development. More powerful coding techniques were developed, commercial firms rolled out new product lines, and the standards organizations rapidly adopted to new technology. The "tipping point" occurred with the introduction of the SupraFAXModem 14400 in 1991. Rockwell had introduced a new chipset supporting not only V.32 and MNP, but the newer 14,400 bit/s V.32bis and the higher-compression V.42bis as well, and even included 9600 bit/s fax capability. Supra, then known primarily for their hard drive systems, used this chip set to build a low-priced 14,400 bit/s modem which cost the same as a 2400 bit/s modem from a year or two earlier (about US$300). The product was a runaway best-seller, and it was months before the company could keep up with demand.

V.32bis was so successful that the older high-speed standards had little to recommend them. USR fought back with a 16,800 bit/s version of HST, while AT&T introduced a one-off 19,200 bit/s method they referred to as V.32ter (also known as V.32 terbo), but neither non-standard modem sold well.

V.34 / 28.8k and 33.6k

An ISA modem manufactured

to conform to the V.34 protocol. Any interest in these systems was destroyed during the lengthy introduction of the 28,800 bit/s V.34 standard. While waiting, several companies decided to "jump the gun" and introduced modems they referred to as "V.FAST". In order to guarantee compatibility with V.34 modems once the standard was ratified (1994), the manufacturers were forced to use more "flexible" parts, generally a DSP and microcontroller, as opposed to purpose-designed "modem chips".

Today the ITU standard V.34 represents the culmination of the joint efforts. It employs the most powerful coding techniques including channel encoding and shape encoding. From the mere 4 bits per symbol (9.6 kbit/s), the new standards used the functional equivalent of 6 to 10 bits per symbol, plus increasing baud rates from 2400 to 3429, to create 14.4, 28.8, and 33.6 kbit/s modems. This rate is near the theoretical Shannon limit. When calculated, the Shannon capacity of a narrowband line is Bandwidth * log2(1 + Pu / Pn), with Pu / Pn the signal-to-noise ratio. Narrowband phone lines have a bandwidth from 300-3100 Hz, so using Pu / Pn = 100,000: capacity is approximately 35 kbit/s.

Without the discovery and eventual application of trellis modulation, maximum telephone rates would have been limited to 3429 baud * 4 bits/symbol == approximately 14 kilobits per second using traditional QAM.

Radio modems

Direct broadcast satellite, WiFi, and mobile phones all use modems to communicate, as do most other wireless services today. Modern telecommunications and data networks also make extensive use of radio modems where long distance data links are required. Such systems are an important part of the PSTN, and are also in common use for high-speed computer network links to outlying areas where fibre is not economical.

Even where a cable is installed, it is often possible to get better performance or make other parts of the system simpler by using radio frequencies and modulation techniques through a cable. Coaxial cable has a very large bandwidth, however signal attenuation becomes a major problem at high data rates if a digital signal is used. By using a modem, a much larger amount of digital data can be transmitted through a single piece of wire. Digital cable television and cable Internet services use radio frequency modems to provide the increasing bandwidth needs of modern households. Using a modem also allows for frequency-division multiple access to be used, making full-duplex digital communication with many users possible using a single wire.

Wireless modems come in a variety of types, bandwidths, and speeds. Wireless modems are often referred to as transparent or smart. They transmit information that is modulated onto a carrier frequency to allow many simultaneous wireless communication links to work simultaneously on different frequencies.

Transparent modems operate in a manner similar to their phone line modem cousins. Typically, they were half duplex, meaning that they could not send and receive data at the same time. Typically transparent modems are polled in a round robin manner to collect small amounts of data from scattered locations that do not have easy access to wired infrastructure. Transparent modems are most commonly used by utility companies for data collection.

Smart modems come with a media access controller inside which prevents random data from colliding and resends data that is not correctly received. Smart modems typically require more bandwidth than transparent modems, and typically achieve higher data rates. The IEEE 802.11 standard defines a short range modulation scheme that is used on a large scale throughout the world.

WiFi and WiMax
Wireless data modems are used in the WiFi and WiMax standards, operating at microwave frequencies.
WiFi (Wireless Fidelity) is principally used in laptops for Internet connections (wireless access point) and wireless application protocol (WAP).

Mobile modems & routers
Modems which use mobile phone lines (GPRS, UMTS, HSPA, EVDO, WiMax, etc.), are known as Cellular Modems. Cellular modems can be embedded inside a laptop or appliance, or they can be external to it. External cellular modems are datacards and cellular routers. The datacard is a PC card or Express Card which slides into a PCMCIA/PC card/ExpressCard slot on a computer. The most famous brand of Radio modem datacards is the AirCard made by Sierra Wireless. (Many people just refer to all makes and models as "Air Cards", when in fact this is a trademarked brand name.) Nowadays, there are USB cellular modems as well that use a USBPC card or ExpressCard slot. A cellular router may or may not have an external data card ("Air Card") that slides into it. Most cellular routers do allow such data cards or USB modems, except for the WAAV, Inc. CM3 mobile broadband cellular router. Cellular Routers may not be modems per Se, but they contain modems or allow modems to be slid into them. The difference between a cellular router and a cellular modem is that a cellular router normally allows multiple people to connect to it (since it can "route"), while the modem is made for one connection.

Most of the GSM cellular modems come with an integrated SIM cardholder (i.e, Huawei E220, Sierra 881, etc.) The CDMA (EVDO) versions do not use SIM cards, but use ESN (Electronic Serial Numbers) instead.

The cost of using a cellular modem varies from country to country. Some carriers implement "flat rate" plans for unlimited data transfers. Some have caps (or maximum limits) on the amount of data that can be transferred per month. Other countries have "per Megabyte" or even "per Kilobyte" plans that charge a fixed rate per Megabyte or Kilobyte of data downloaded; this tends to add up quickly in today's content-filled world, which is why many people are pushing for flat data rates. See flat rate.

The faster data rates of the newest cellular modem technologies (UMTS,HSPA,EVDO,WiMax) are also considered to be "Broadband Cellular Modems" and compete with other Broadband modems below.

Broadband

DSL modem

ADSL modems, a more recent development, are not limited to the telephone's "voiceband" audio frequencies. Some ADSL modems use coded orthogonal frequency division modulation (DMT). Cable modems use a range of frequencies originally intended to carry RF television channels. Multiple cable modems attached to a single cable can use the same frequency band, using a low-level media access protocol to allow them to work together within the same channel. Typically, 'up' and 'down' signals are kept separate using frequency division multiple access. New types of broadband modems are beginning to appear, such as doubleway satellite and power line modems. Broadband modems should still be classed as modems, since they use complex waveforms to carry digital data. They are more advanced devices than traditional dial-up modems as they are capable of modulating/demodulating hundreds of channels simultaneously. Many broadband modems include the functions of a router (with Ethernet and WiFi ports) and other features such as DHCP, NAT and firewall features. When broadband technology was introduced, networking and routers were unfamiliar to consumers. However, many people knew what a modem was as most internet access was through dial-up. Due to this familiarity, companies started selling broadband modems using the familiar term "modem" rather than vaguer ones like "adapter" or "transceiver". Many broadband modems must be configured in bridge mode before they can use a router.

Deep-space telecommunications
Many modern modems have their origin in deep space telecommunications systems of the 1960s.

Differences with deep space telecoms modems vs landlines modems

digital modulation formats that have high Doppler immunity are typically used
waveform complexity tends to be low, typically binary phase shift keying
error correction varies mission to mission, but is typically much stronger than most landlines modems

Voice modem
Voice modems are regular modems that are capable of recording or playing audio over the telephone line. They are used for telephony applications. See Voice modem command set for more details on voice modems. This type of modem can be used as FXO card for Private branch exchange systems (compare V.92).

Visual Display Unit (VDU)

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Visual Display Unit (VDU)

Visual display unit, often called simply a monitor or display, is a piece of electrical equipment which displays images generated from the video output of devices such as computers, without producing a permanent record. A newer monitor typically consists of a TFT LCD, with oldest monitors based around a cathode ray tube (CRT). The monitor comprises the display device, simple circuitry to generate and format a picture from video sent by the signals source, and usually an enclosure. Within the signal source, either as an integral section or a modular component, there is a display adapter to generate video in a format compatible with the monitor.

Imaging technologies:

19" inch
(48.3 cm tube,
45.9 cm viewable)
View Sonic CRT
computer monitor.

As with television, many different hardware technologies exist for displaying computer-generated output:

Liquid crystal display (LCD). TFT LCDs are the most popular display device for new computer.
- LCDs produce poor contrast, slow response, and other image defects. These were used in most laptops until the mid 1990s.
- Film Transistor LCDs give much better picture quality in several respects. Nearly all modern LCD monitors are TFT.

Cathode ray tube (CRT)
- Raster scan computer monitors, which produce images using pixels. These were the most popular display device for older computers.
- Displays, as used on the Vectrex, many scientific and radar applications, and several early arcade machines (notably Asteroids) - always implemented using CRT displays due to requirement for a deflection system, though can be emulated on any raster-based display.
- Television sets were used by most early personal and home computers, connecting composite video to the television set using a modulator. Resolution and image quality were strongly limited by the display capabilities of television.

Plasma display
Video projectors use CRT, LCD, DLP, LCoS or many other technologies to send light through the air to a projection screen. Front projectors use screens as reflectors to send light back, while rear projectors use screens as diffusers to refract light forward. Rear projectors are often integrated into the same case as their screen.

Surface-conduction electron-emitter display (SED)
Organic light-emitting diode (OLED) display
Penetron military aircraft displays

Comparison

CRT

Pros:

Very high contrast ratio (20,000:1 or greater, much higher than many modern LCDs and plasma displays.)
High speed response.
Excellent Additive color, wide gamut and low black level limited only by external environment.
Can display natively in almost any resolution and refresh rate.
Near zero color, saturation, contrast or brightness distortion. Excellent viewing angle.
No input lag.
A reliable, proven display technology.

Cons:

Large size and weight (a 40" unit weighs over 200lbs)
Geometric distortion in non-flat CRTs
Older CRTs are prone to burn-in.
Warm up time required prior to peak luminance and proper color rendering.
Greater power consumption than similarly sized displays, such as LCD.
Screened devices are prone to moire effect at highest resolution (does not apply to triple-tube projection)
Intolerant of damp conditions, with dangerous wet failure characteristics.
Small risk of implosion (due to internal vacuum) if the picture tube is broken in aging sets.
Use under Lower refresh rates causes noticeable flicker
Internal lethally high voltages
Flyback transformer produces characteristic high-pitched noise when close to set.
Increasingly difficult to obtain models at HDTV resolutions, due to consumers' perception of antiquity.

LCD

Pros:

Very compact and light
Low power consumption
No geometric distortion
Rugged
Little or no flicker depending on back light.

Cons:

Low contrast ratio.
Limited viewing angle. This causes color, saturation, contrast and brightness to vary, even within the intended viewing angle from mere variations in posture.
Uneven backlighting in some monitors can cause brightness distortion, especially toward the edges.
Slow response times, which cause smearing and ghosting artifacts (although many modern LCDs have response times of 8ms or less).
Only has one native resolution. Displaying other resolutions requires a video scaler, which degrades image quality at lower resolutions.
Fixed bit depth, many cheaper LCDs are incapable of truecolor.
Input lag
Somewhat more expensive than CRT
Dead pixels are possible during manufacturing

Plasma

Pros:

Compact and light
High contrast ratios (10,000:1 or greater)
High speed response
Excellent color, wide gamut and low black level.
Near zero color, saturation, contrast or brightness distortion. Excellent viewing angle.
No geometric distortion
Highly scalable, with less weight gain per increase in size (from less than 30 inches wide to the world's largest at 150 inches).

Cons:

Large pixel pitch means either low resolution or a large screen
Noticeable flicker when viewed at close range
High operating temperature
Somewhat more expensive than LCD
High power consumption
Only has one native resolution. Displaying other resolutions requires a video scaler, which degrades image quality at lower resolutions.
Fixed bit depth
Input lag
Older PDPs are prone to burn-in
Dead pixels are possible during manufacturing

Penetron

Pros:

See-through for transparent HUDs (although LCDs are also transparent, they are not self-lighting.)
Very high contrast ratios.
Extremely sharp.

Cons:

Color displays are limited to about four tints.
Orders of magnitude more expensive than the other display technologies listed here.

Modern technology

Analog monitors
Most modern computer displays can show an infinite number of different colors in the RGB color space by changing red, green, and blue analog video signals in continuously variable intensities. These have been almost exclusively progressive scan since the middle 1980s. While many early plasma and liquid crystal displays have exclusively analog connections, all signals in such monitors pass through a completely digital section prior to display.

Computer & Analog Monitor

While many similar connectors (13W3, BNC, etc…) were used on other platforms, the IBM PCVGA connector. All of these connectors deliver nearly flawless high resolution video which vastly outclasses that of a TV. and compatible systems long ago standardized on the

Digital and analog combination
The first popular external digital monitor connectors, such as DVI-I and the various breakout connectors based on it, included both analog signals compatible with VGA and digital signals compatible with new flat-screen displays in the same connector. This made the connector nearly painless for users of both technologies.

Digital Analog Watch

Digital monitors
Newer connectors are being made which have digital only video signals. Many of these, such as HDMI and DisplayPort, also feature integrated audio and data connections. One less popular feature most of these connectors share are DRM encrypted signals, although the HDCP technology responsible for implementing the protection was necessarily rudimentary to meet cost constraints, and was primarily a barrier aimed towards dissuading average consumers from creating exact duplicates without a noticeable loss in image quality.

Magnetic Ink Character Recognition

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Magnetic Ink Character Recognition
Magnetic Ink Character Recognition, or MICR (pronounced my-ker or micker), a character recognition technology adopted mainly by the banking industry to facilitate the processing of checks. The process was demonstrated to the American Bankers Association in July 1956, and was almost universally employed in the U.S. by 1963. On September 12, 1961, Stanford Research Institute (now SRI International) was awarded U.S. Patent Number 3,000,000 for invention of MICR; the patent was assigned to General Electric. MICR is standardized by ISO 1004. The major MICR fonts used around the world are E-13B and CMC-7. The E-13B font was chosen by George Jacobi, who was working for General Electric at the time.[citation needed]Bull. Almost all Indian, US, Canadian and UK checks now include MICR characters at the bottom of the paper in the E-13B font. Some countries, including France, use the CMC-7 font developed by the 14 characters of the E-13B font. The control characters bracketing each numeral block are (from left to right) transit, on-us, amount, and dash. An example of the CMC-7 MICR font. Shown are the 15 characters of the CMC-7 font. The control characters after the numerals are (from left to right) internal, terminator, amount, routing, and an unused character. In addition to their unique fonts, MICR characters are printed with a magnetic ink or toner, usually containing iron oxide. Magnetic printing is used so that the characters can be reliably read into a system, even when they have been overprinted with other marks such as cancellation stamps. The characters are first magnetized in the plane of the paper with a North pole on the right of each MICR character. Then they are usually read with a MICR read head which is a device similar in nature to the playback head in an audio tape recorder, and the letterforms' bulbous shapes ensure that each letter produces a unique waveform for the character recognition system to provide a reliable character result. Examples of MICR waveforms have been developed and can be displayed using spreadsheet applications like Microsoft Excel or compatible.

The error rate for the magnetic scanning of the numbers at the bottom of a typical check is smaller than with optical character recognition systems. For well printed MICR, the can't read rate is usually less than 1% while the substitution rate (misread rate) is in the order of 1 per 100,000 characters.

In 1960s, the MICR fonts became a symbol of modernity, leading to the creation of lookalike "computer" typefaces that imitated the appearance of the MICR fonts, but, unlike real MICR fonts, had a full character repertoire.

In 1991, Advantage Laser Products became the first toner cartridge manufacturer to offer MICR toner in lieu of MICR Ink for desktop laser printers. This revolutionized the check printing business. Prior to 1991 checks were printed with magnetic ink on an offset press. With the advent of MICR toner, checks could be printed on almost any desktop laser printer.

WHAT IS MICR?

Magnetic Ink Character Recognition (MICR), as defined by the American National Standards Institute (ANSI), is the common machine language specification for the paper-based payment transfer system. It consists of magnetic ink printed characters of a special design which can be recognized by high speed magnetic recognition equipment. This series of readable characters provides the receiving party with information needed for processing the check including: check number, bank routing number, checking account number and in some cases the amount of the check.
MICR characters are printed in the form of either an E-13B or CMC-7 Font. Each font series is made up of a series of numbers and symbols specifically designed for readability on check sorting machines which read at extremely high rates of speed. The symbols provide a beginning and ending point for each group of numbers allowing the machine to quickly determine what each series of number signifies. Line placement, character placement, skew and quality are several critical components of printing MICR; the line must be precisely positioned in the MICR Clear Band area. To create consistency in the check clearing process it is critical that each character is readable and that the printing methods are reliable.

MICR, Magnetic Ink Character Recognition:
MICR is the technology which allows the characters printed on the bottom of the check to be read by reader-sorter machines. A special formulation of ink or toner, MICR can be printed with impact machines, on a printing press, or a laser printer.

The magnetically charged printing allows each character to be recognized based on the magnetic signal created by each character’s unique shape. These shapes create a unique magnetic “fingerprint” which allows the reader-sorter machines to recognize each character. Since MICR is a machine readable process, it is imperative that each character is accurately placed and is free of irregular marks or voids. The uniformity of print is another key component to readability.

MICR Printing:
Checks can be ordered with the MICR Characters already printed in the clear band of each check. This is known as a pre-printed check; these checks are typically printed by a production house utilizing high speed impact equipment and ship based on minimum order quantities. Pre -printed checks can be costly if purchased in small quantities.

Another option is to order blank checks where the MICR Characters are printed at the same time you print the checks. Other checks are typically printing using a laser printer on a blank check stock, in this case the MICR line is printed at the point in time when the check is created and the MICR line often contains the amount. When check printing is done in-house it is important to verify that all of the necessary elements for printing the MICR Line are in place. In order to printer your checks you will need a check writing software, which provides check formatting, blank check stock, MICR Toner, as well as a printer capable of printing MICR.

MICR Toner:
MICR Toner provides the ability to print checks on demand using a desktop laser printer with blank check stock. The toners are formulated with a special grade of magnetic iron oxide which provides the characters with a magnetic signal. Should you attempt to print checks with standard (non-magnetic) toner the characters will appear visually to be correct, but they will not be magnetically readable by a reader-sorter. The net results are check rejects at the clearing center and often times additional check processing charges imposed by the banks. Some areas to consider when deciding which MICR Toner cartridge to purchase include: cartridge type (new or remanufactured), cartridge brand (manufacturer) and cartridge price. Purchasing premium cartridges, a cartridge which has not been previously used, typically provides more reliable cartridge performance and consistent yields (or total number of prints per cartridge). When purchasing a remanufactured cartridge, yields and consistency can often be compromised.

Printers

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Printers

In computing, a printer is a peripheral which produces a hard copy (permanent human-readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a USB cable to a computer which serves as a document source. Some printers, commonly known as network printers, have built-in network interfaces (typically wireless or Ethernet), and can serve as a hardcopy device for any user on the network. Individual printers are often designed to support both local and network connected users at the same time.

In addition, a few modern printers can directly interface to electronic media such as memory sticks or memory cards, or to image capture devices such as digital cameras, scanners; some printers are combined with a scanners and/or fax machines in a single unit, and can function as photocopiers. Printers that include non-printing features are sometimes called Multifunction Printers (MFP), Multi-Function Devices (MFD), or All-In-One (AIO) printers. Most MFPs include printing, scanning, and copying among their features.

Printers are designed for low-volume, short-turnaround print jobs; requiring virtually no setup time to achieve a hard copy of a given document. However, printers are generally slow devices (30 pages per minute is considered fast; and many consumer printers are far slower than that), and the cost-per-page is relatively high. The printing press remains the machine of choice for high-volume, professional publishing. However, as printers have improved in quality and performance, many jobs which used to be done by professional print shops are now done by users on local printers; see desktop publishing. The world's first computer printer was a 19th century mechanically driven apparatus invented by Charles Babbage for his Difference Engine.

Modern Print Technology

The following printing technologies are routinely found in modern printers, as of April 2006:

Toner based Printers

Toner-based printers work using the Xerographic principle that is used in most photocopiers: by adhering toner to a light-sensitive print drum, then using static electricity to transfer the toner to the printing medium to which it is fused with heat and pressure.

The most common type of toner-based printer is the laser printer, which uses precision lasers Laser printers are known for high quality prints, good print speed, and a low (Black and White) cost-per-copy. They are the most common printer for many general-purpose office applications, but are much less common as consumer printers due to their high initial cost - although this cost is dropping to cause toner adherence.

Laser printers are available in both color and monochrome varieties.

Another toner based printer is the LED printer which uses an array of LEDs instead of a laser to cause toner adhesion to the print drum

LED Printers (Color):

Recent research has also indicated that Laser printers emit potentially dangerous ultra fine particles, possibly causing health problems associated with respiration and cause pollution equivalent to cigarettes. Degree of particle emissions varies with age, model and design of each printer but is generally proportional to the amount of toner required. Furthermore, a well ventilated workspace would allow such ultra fine particles to disperse thus reducing the health side effects.

Ink Jet Printers:

Inkjet printers operate by propelling variably-sized droplets of liquid or molten material (ink) onto almost any sized page. They are the most common type of computer printer for the general consumer [citation needed] due to their low cost, high quality of output, capability of printing in vivid color, and ease of use.

Solid Ink Printers:

Solid Ink printers, also known as phase-change printers, are a type of thermal transfer printer. They use solid sticks of CMYK colored ink (similar in consistency to candle wax), which are melted and fed into a piezo crystal operated print-head. The printhead sprays the ink on a rotating, oil coated drum. The paper then passes over the print drum, at which time the image is transferred, or transfixed, to the page.

Solid ink printers are most commonly used as color office printers, and are excellent at printing on transparencies and other non-porous media. Solid ink printers can produce excellent results. Acquisition and operating costs are similar to laser printers. Drawbacks of the technology include high power consumption and long warm-up times from a cold state.

Also, some users complain that the resulting prints are difficult to write on (the wax tends to repel inks from pens), and are difficult to feed through Automatic Document Feeders, but these traits have been significantly reduced in later models. In addition, this type of printer is only available from one manufacturer, Xerox, manufactured as part of their Xerox Phasersolid ink printers were manufactured by Tektronix, but Tek sold the printing business to Xerox in 2001 office printer line. Previously,

Dye-Sublimation Printer:
A dye-sublimation printer (or dye-sub printer) is a printer which employs a printing process that uses heat to transfer dye to a medium such as a plastic card, paper or canvas. The process is usually to lay one color at a time using a ribbon that has color panels. Dye-sub printers are intended primarily for high-quality color applications, including color photography; and are less well-suited for text. While once the province of high-end print shops, dye-sublimation printers are now increasingly used as dedicated consumer photo printers.

Ink Less Printer:

Thermal Printers:

Thermal printers work by selectively heating regions of special heat-sensitive paper. Monochrome thermal printers are used in cash registers, ATMs, gasoline dispensers and some older inexpensive fax machines. Colors can be achieved with special papers and different temperatures and heating rates for different colors. One example is the ZINK technology.

UV Printers:

Xerox is working on an inkless printer which will use a special reusable paper coated with a few micrometers of UV light sensitive chemicals. The printer will use a special UV light bar which will be able to write and erase the paper. As of early 2007 this technology is still in development and the text on the printed pages can only last between 16-24 hours before fading.

Impact printers rely on a forcible impact to transfer ink to the media, similar to the action of a typewriter. All but the dot matrix printer rely on the use of formed characters, letter forms that represent each of the characters that the printer was capable of printing. In addition, most of these printers were limited to monochrome printing in a single typeface at one time, although bolding and underlining of text could be done by over striking, that is, printing two or more impressions in the same character position. Impact printer’s varieties include Typewriter-derived printers, Teletypewriter-derived printers, Daisy wheel printers, Dot matrix printers and Line printers. Dot matrix printers remain in common use in businesses where multi-part forms are printed, such as car rental service counters.

Type-Writer Derived Printers:

Several different computer printers were simply computer-controllable versions of existing electric typewriters. The Friden Flexowriter and IBM Selectric typewriter were the most-common examples. The Flexowriter printed with a conventional type bar mechanism while the Selectric used IBM's well-known "golf ball" printing mechanism. In either case, the letter form then struck a ribbon which was pressed against the paper, printing one character at a time. The maximum speed of the Selectric printer (the faster of the two) was 15.5 characters per second.

Teletypewriter derived Printers:

The common teleprinter could easily be interfaced to the computer and became very popular except for those computers manufactured by IBM. Some models used a "type-box" that was positioned (in the X- and Y-axes) by a mechanism and the selected letter from was struck by a hammer. Others used a type cylinder in a similar way as the Selectric typewriters used their type ball. In either case, the letter form then struck a ribbon to print the letter form. Most teleprinters operated at ten characters per second although a few achieved 15 CPS.

Daisy-Wheel Printers:

Daisy-wheel printers operate in much the same fashion as a typewriter. A hammer strikes a wheel with petals (the daisy wheel), each petal containing a letter form at its tip. The letter form strikes a ribbon of ink, depositing the ink on the page and thus printing a character. By rotating the daisy wheel, different characters are selected for printing.

These printers were also referred to as letter-quality printers because, during their heyday, they could produce text which was as clear and crisp as a typewriter (though they were nowhere near the quality of printing presses). The fastest letter-quality printers printed at 30 characters per second.

Dot-Matrix Printer:

In the general sense many printers rely on a matrix of pixels, or dots, that together form the larger image. However, the term dot matrix printer is specifically used for impact printers that use a matrix of small pins to create precise dots. The advantage of dot-matrix over other impact printers is that they can produce graphical images in addition to text; however the text is generally of poorer quality than impact printers that use letter forms (type).

A Tandy 1000 HX with a Tandy DMP-133 dot-matrix printer.

Dot-matrix printers can be broadly divided into two major classes:

* Ballistic wire printers (discussed in the dot matrix printers article)

* Stored energy printers

Dot matrix printers can either be character-based or line-based (that is, a single horizontal series of pixels across the page), referring to the configuration of the print head.

At one time, dot matrix printers were one of the more common types of printers used for general use - such as for home and small office use. Such printers would have either 9 or 24 pins on the print head. 24-pin print heads were able to print at a higher quality. Once the price of inkjet printers dropped to the point where they were competitive with dot matrix printers, dot matrix printers began to fall out of favor for general use.

Some dot matrix printers, such as the NEC P6300, can be upgraded to print in color. This is achieved through the use of a four-color ribbon mounted on a mechanism (provided in an upgrade kit that replaces the standard black ribbon mechanism after installation) that raises and lowers the ribbons as needed. Color graphics are generally printed in four passes at standard resolution, thus slowing down printing considerably. As a result, color graphics can take up to four times longer to print than standard monochrome graphics, or up to 8-16 times as long at high resolution mode.

Dot matrix printers are still commonly used in low-cost, low-quality applications like cash registers, or in demanding, very high volume applications like invoice printing. The fact that they use an impact printing method allows them to be used to print multi-part documents using carbonless copy paper (like sales invoices and credit card receipts), whereas other printing methods are unusable with paper of this type. Dot-matrix printers are now (as of 2005) rapidly being superseded even as receipt printers.

Line Printers:

Line printers, as the name implies, print an entire line of text at a time. Three principal designs existed. In drum printers, a drum carries the entire character set of the printer repeated in each column that is to be printed. In chain printers (also known as train printers), the character set is arranged multiple times around a chain that travels horizontally past the print line. In either case, to print a line, precisely timed hammers strike against the back of the paper at the exact moment that the correct character to be printed is passing in front of the paper. The paper presses forward against a ribbon which then presses against the character form and the impression of the character form is printed onto the paper.

Comb printers represent the third major design. These printers were a hybrid of dot matrix printing and line printing. In these printers, a comb of hammers printed a portion of a row of pixels at one time (for example, every eighth pixel). By shifting the comb back and forth slightly, the entire pixel row could be printed (continuing the example, in just eight cycles). The paper then advanced and the next pixel row was printed. Because far less motion was involved than in a conventional dot matrix printer, these printers were very fast compared to dot matrix printers and were competitive in speed with formed-character line printers while also being able to print dot-matrix graphics.

Line printers were the fastest of all impact printers and were used for bulk printing in large computer centers. They were virtually never used with personal computers and have now been replaced by high-speed laser printers.