76-470: The Electronic Industries Alliance ( EIA ; until 1997 Electronic Industries Association ) was an American standards and trade organization composed as an alliance of trade associations for electronics manufacturers in the United States. They developed standards to ensure the equipment of different manufacturers was compatible and interchangeable. The EIA ceased operations on February 11, 2011, but
152-538: A Recommended Standard , thus the " RS " RS-232 . Later it was taken over by the EIA as EIA-232 . Later this standard was managed by the TIA and the name was changed to the current TIA-232 . Because the EIA was accredited by ANSI to help develop standards in its areas, these standards are often described as (e.g. ANSI TIA-232 , or formerly as ANSI EIA/TIA-232 ). As currently authorized, any ANSI standard designated at ANSI EIA-xxx
228-519: A memorandum of understanding to collaborate on the United States Standards Strategy. The determinates of whether an NSB for a particular economy is a public or private sector body may include the historical and traditional roles that the private sector fills in public affairs in that economy or the development stage of that economy. A national standards body (NSB) generally refers to one standardization organization that
304-471: A command string is terminated with a CR (\r) character Although not part of the command set, a tilde character ~ is commonly used in modem command sequences. The ~ causes many applications to pause sending the command stream to the device (usually for half a second), e.g. after a Reset . The ~ is not sent to the modem. Command options: The ITU-T established a standard in its V-Series Recommendations , V.25 ter , in 1995 in an attempt to establish
380-407: A company offers a product that is "compliant" with a standard. When an organization develops standards that may be used openly, it is common to have formal rules published regarding the process. This may include: Though it can be a tedious and lengthy process, formal standard setting is essential to developing new technologies. For example, since 1865, the telecommunications industry has depended on
456-509: A hierarchical fashion in terms of national, regional and international scope; international organizations tend to have as members national organizations; and standards emerging at national level (such as BS 5750 ) can be adopted at regional levels (BS 5750 was adopted as EN 29000) and at international levels (BS 5750 was adopted as ISO 9000). Unless adopted by a government, standards carry no force in law. However, most jurisdictions have truth in advertising laws, and ambiguities can be reduced if
532-892: A large variety of independent international standards organizations such as the ASME , ASTM International , the International Commission on Illumination (CIE) , the IEEE , the Internet Engineering Task Force (IETF), SAE International , TAPPI , the World Wide Web Consortium (W3C), and the Universal Postal Union (UPU) develop and publish standards for a variety of international uses. In many such cases, these international standards organizations are not based on
608-402: A number of branch offices for end-of-day processing. To fill this role, some modems included the ability to pick up the phone automatically when it was in answer mode, and to clear the line when the other user manually disconnected. The need for automated outbound dialling was considerably less common, and was handled through a separate peripheral device: a "dialler". This was normally plugged into
684-401: A number of discrete commands can be concatenated after the "AT". The Hayes command set can subdivide into four groups: Although the command-set syntax defines most commands by a letter-number combination (L0, L1 etc.), the use of a zero is optional. In this example, "L0" equates to a plain "L". Keep this in mind when reading the table below. When in data mode, an escape sequence can return
760-481: A particular country, while others have been built from scratch by groups of experts who sit on various technical committees (TCs). These three organizations together comprise the World Standards Cooperation (WSC) alliance. ISO is composed of the national standards bodies (NSBs), one per member economy. The IEC is similarly composed of national committees, one per member economy. In some cases,
836-426: A pause of about a second. The pause at the end of the escape sequence was required to reduce the problem caused by in-band signaling : if any other data was received within one second of the three plus signs, it was not the escape sequence and would be sent as data. To switch back they sent the online command, ATO . In actual use many of the commands automatically switched to the online mode after completion, and it
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#1732786598870912-611: A permanent agency of the United Nations , in which governments are the primary members, although other organizations (such as non-governmental organizations and individual companies) can also hold a form of direct membership status in the ITU as well. Another example of a treaty-based international standards organization with government membership is the Codex Alimentarius Commission . In addition to these,
988-408: A product or process is safe for humans, animals, and the environment. The subject of their work can be narrow or broad. Another area of interest is in defining how the behavior and performance of products is measured and described in data sheets. Overlapping or competing standards bodies tend to cooperate purposefully, by seeking to define boundaries between the scope of their work, and by operating in
1064-1177: A proposal to form a new global standards body. In October 1946, ISA and UNSCC delegates from 25 countries met in London and agreed to join forces to create the new International Organization for Standardization ; the new organization officially began operations in February ;1947. Standards organizations can be classified by their role, position, and the extent of their influence on the local, national, regional, and global standardization arena. By geographic designation, there are international, regional, and national standards bodies (the latter often referred to as NSBs). By technology or industry designation, there are standards developing organizations (SDOs) and also standards setting organizations (SSOs) also known as consortia. Standards organizations may be governmental, quasi-governmental or non-governmental entities. Quasi- and non-governmental standards organizations are often non-profit organizations. Broadly, an international standards organization develops international standards (this does not necessarily restrict
1140-406: A separate input/output port on the computer (typically an RS-232 port) and programmed separately from the modem itself. This method of operation worked satisfactorily in the 1960s and early 1970s, when modems were generally used to connect dumb devices like computer terminals (dialling out) with smart mainframe computers (answering). However, the microcomputer revolution of the 1970s led to
1216-456: A standard for the command set again. It was renamed V.250 in 1998 with an annex that was not concerning the Hayes command set renamed as V.251 . A V.250 compliant modem implements the A, D, E, H, I, L, M, N, O, P, Q, T, V, X, Z, &C, &D, and &F commands in the way specified by the standard. It must also implement S registers and must use registers S0, S3, S4, S5, S6, S7, S8, and S10 for
1292-410: A technological baseline for future research and product development. Formal standard setting through standards organizations has numerous benefits for consumers including increased innovation, multiple market participants, reduced production costs, and the efficiency effects of product interchangeability. To support the standard development process, ISO published Good Standardization Practices (GSP) and
1368-496: A university may have copies of technical standards on hand. Major libraries in large cities may also have access to many technical standards. Some users of standards mistakenly assume that all standards are in the public domain . This assumption is correct only for standards produced by the central governments whose publications are not amenable to copyright or to organizations that issue their standard under an open license. Any standards produced by non-governmental entities remain
1444-472: A virtual Ethernet interface instead of using a Point-to-Point Protocol (PPP) for the data connection because of performance reasons (PPP connection is only used between the computer and the modem, not over network). The set-up requires vendor-specific AT command extensions. Sometimes the specifications for these extensions are openly available, other times the vendor requires an NDA for access to these. Modems with voice or answering-machine capabilities support
1520-828: Is developed or managed by ECA (and, in the future, ECIA). Standards organization A standards organization , standards body , standards developing organization ( SDO ), or standards setting organization ( SSO ) is an organization whose primary function is developing, coordinating, promulgating, revising, amending, reissuing, interpreting, or otherwise contributing to the usefulness of technical standards to those who employ them. Such an organization works to create uniformity across producers, consumers, government agencies, and other relevant parties regarding terminology, product specifications (e.g. size, including units of measure), protocols, and more. Its goals could include ensuring that Company A's external hard drive works on Company B's computer, an individual's blood pressure measures
1596-464: Is rare for a user to use the online command explicitly. In order to avoid licensing Hayes's patent, some manufacturers implemented the escape sequence without the time guard interval ( Time Independent Escape Sequence (TIES)). This had a major denial of service security implication in that it would lead to the modem hanging up the connection should the computer ever try to transmit the byte sequence +++ATH0 in data mode. For any computer connected to
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#17327865988701672-545: Is that country's member of the ISO . A standards developing organization (SDO) is one of the thousands of industry- or sector-based standards organizations that develop and publish industry specific standards. Some economies feature only an NSB with no other SDOs. Large economies like the United States and Japan have several hundred SDOs, many of which are coordinated by the central NSBs of each country (ANSI and JISC in this case). In some cases, international industry-based SDOs such as
1748-612: The AT command set ) is a specific command language originally developed by Dale Heatherington and Dennis Hayes for the Hayes Smartmodem in 1981. The command set consists of a series of short text strings which can be combined to produce commands for operations such as dialing, hanging up, and changing the parameters of the connection. The vast majority of dial-up modems use the Hayes command set in numerous variations. The command set covered only those operations supported by
1824-864: The African Organisation for Standardisation (ARSO), the Arabic industrial development and mining organization (AIDMO), and others. In the European Union, only standards created by CEN, CENELEC, and ETSI are recognized as European standards (according to Regulation (EU) No 1025/2012 ), and member states are required to notify the European Commission and each other about all the draft technical regulations concerning ICT products and services before they are adopted in national law. These rules were laid down in Directive 98/34/EC with
1900-719: The CIE , the IEEE and the Audio Engineering Society (AES) may have direct liaisons with international standards organizations, having input to international standards without going through a national standards body. SDOs are differentiated from standards setting organizations (SSOs) in that SDOs may be accredited to develop standards using open and transparent processes. Developers of technical standards are generally concerned with interface standards , which detail how products interconnect with each other, and safety standards , which established characteristics ensure that
1976-707: The GCC Standardization Organization (GSO) for Arab States of the Persian Gulf . In general, each country or economy has a single recognized national standards body (NSB). A national standards body is likely the sole member from that economy in ISO; ISO currently has 161 members. National standards bodies usually do not prepare the technical content of standards, which instead is developed by national technical societies. NSBs may be either public or private sector organizations, or combinations of
2052-544: The Hayes command set developed by Hayes , Apple 's TrueType font design and the PCL protocol used by Hewlett-Packard in the computer printers they produced. Normally, the term standards organization is not used to refer to the individual parties participating within the standards developing organization in the capacity of founders, benefactors , stakeholders , members or contributors, who themselves may function as or lead
2128-516: The ITU to establish the telecommunications standards that have been adopted worldwide. The ITU has created numerous telecommunications standards including telegraph specifications, allocation of telephone numbers, interference protection, and protocols for a variety of communications technologies. The standards that are created through standards organizations lead to improved product quality, ensured interoperability of competitors' products, and they provide
2204-675: The National Electronic Distributors Association (NEDA) in 2011 to form the Electronic Components Industry Association (ECIA). However, the EIA standards brand will continue for IP&E standards within ECIA. With the changing names of the EIA, the naming convention of the standards was also adapted. For example, a standard defining serial communication between computers and modems e.g. was originally drafted as
2280-825: The OpenOffice.org , an Apache Software Foundation -sponsored international community of volunteers working on an open-standard software that aims to compete with Microsoft Office , and two commercial groups competing fiercely with each other to develop an industry-wide standard for high-density optical storage . Another example is the Global Food Safety Initiative where members of the Consumer Goods Forum define benchmarking requirements for harmonization and recognize scheme owners using private standards for food safety . Hayes command set The Hayes command set (also known as
2356-556: The Short Message Service (SMS) feature of GSM. Examples of GSM commands: GSM/3G modems typically support the ETSI GSM 07.07/3GPP TS 27.007 AT command set extensions, although how many commands are implemented varies. Most USB modem vendors, such as Huawei, Sierra Wireless, Option, have also defined proprietary extensions for radio mode selection (GSM/3G preference) or similar. Some recent high speed modems provide
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2432-645: The WTO Technical Barriers to Trade (TBT) Committee published the "Six Principles" guiding members in the development of international standards. Some standards – such as the SIF Specification in K12 education – are managed by a non-profit organizations composed of public entities and private entities working in cooperation that then publish the standards under an open license at no charge and requiring no registration. A technical library at
2508-726: The World Health Organization Guidelines in health, or ITU Recommendations in ICT and being publicly funded, are freely available for consideration and use worldwide. In 1904, Crompton represented Britain at the Louisiana Purchase Exposition in St. Louis , Missouri , as part of a delegation by the Institute of Electrical Engineers . He presented a paper on standardization, which
2584-462: The World Wide Web Consortium (W3C), whose standards for HTML , CSS , and XML are used universally. There are also community-driven associations such as the Internet Engineering Task Force (IETF), a worldwide network of volunteers who collaborate to set standards for internet protocols. Some industry-driven standards development efforts don't even have a formal organizational structure. They are projects funded by large corporations. Among them are
2660-406: The intellectual property of their developers (unless specifically designed otherwise) and are protected, just like any other publications , by copyright laws and international treaties . However, the intellectual property extends only to the standard itself and not to its use. For instance if a company sells a device that is compliant with a given standard, it is not liable for further payment to
2736-897: The ARINC Standards. Regional standards bodies also exist, such as the European Committee for Standardization (CEN), the European Committee for Electrotechnical Standardization (CENELEC), the European Telecommunications Standards Institute (ETSI), and the Institute for Reference Materials and Measurements (IRMM) in Europe, the Pacific Area Standards Congress (PASC), the Pan American Standards Commission (COPANT),
2812-591: The Hayes extensions after the introduction of the SupraFAXModem 14400 and the market consolidation that followed. The term " Hayes compatible " was and as of 2018 still is important within the industry. Before the introduction of the bulletin board system (BBS), modems typically operated on direct-dial telephone lines that began and ended with a known modem at each end. The modems operated in either "originate" or "answer" modes, manually switching between two sets of frequencies for data transfer. Generally,
2888-537: The Internet through such a modem, this could be easily exploited by sending it a ping of death request containing the sequence +++ATH0 in the payload. The computer operating system would automatically try to reply the sender with the same payload, immediately disconnecting itself from the Internet, as the modem would interpret the ICMP data payload as a Hayes command. The same error would also trigger if, for example,
2964-463: The RS-232 interface transmits least significant bit first, the according line pattern with 8-N-1 (eight data bits, no parity bit, one stop bit) is 0 10000010 10 00101010 1 (start and stop bits italicized ) which is used as syncword . The following commands are understood by virtually all modems supporting an AT command set, whether old or new. P – Pulse Dial T – Touch Tone Dial W – Wait for
3040-434: The RS-232 port on microcomputers were extremely basic, and some eliminated many of these pins to reduce cost. Hayes Communications introduced a solution in its 1981 Smartmodem by using the existing data pins with no modification. Instead, the modem itself could be switched between one of two modes: To switch from data mode to command mode, sessions sent an escape sequence string of three plus signs ( +++ ) followed by
3116-507: The body's first President. The International Federation of the National Standardizing Associations (ISA) was founded in 1926 with a broader remit to enhance international cooperation for all technical standards and specifications. The body was suspended in 1942 during World War II . After the war, ISA was approached by the recently formed United Nations Standards Coordinating Committee (UNSCC) with
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3192-657: The command sets were identical as a time-saving method. Essentially by accident, this allowed users of existing 1200 baud modems to use the new Hayes 2400 models without changing their software. This re-inforced the use of the Hayes versions of these commands. Years later, the Telecommunications Industry Association (TIA)/ Electronic Industries Alliance (EIA) formally standardized the 2400-baud command set as Data Transmission Systems and Equipment – Serial Asynchronous Automatic Dialing and Control , TIA/EIA-602 . However, Hayes Communications
3268-432: The command. While the original Hayes command set represented a huge leap forward in modem-based communications, with time many problems set in, almost none of them due to Hayes per se : As a result of all this, eventually many communications programs had to give up any sense of being able to talk to all "Hayes-compatible" modems, and instead the programs had to try to determine the modem type from its responses, or provide
3344-515: The contributions of other engineers, accomplished a modest amount of industry standardization; some companies' in-house standards also began to spread more widely within their industries. Joseph Whitworth 's screw thread measurements were adopted as the first (unofficial) national standard by companies around Britain in 1841. It came to be known as the British Standard Whitworth , and was widely adopted in other countries. By
3420-452: The cost of a separate port , which a microcomputer might not have available. Another solution would have been to use a separate set of "command pins" dedicated to sending and receiving commands; another could have used a signal pin indicating that the modem should interpret incoming data as a command. Both of these had hardware support in the RS-232 standard. However, many implementations of
3496-835: The country, and enabled the markets to act more rationally and efficiently, with an increased level of cooperation. After the First World War , similar national bodies were established in other countries. The Deutsches Institut für Normung was set up in Germany in 1917, followed by its counterparts, the American National Standard Institute and the French Commission Permanente de Standardisation , both in 1918. Several international organizations create international standards , such as Codex Alimentarius in food,
3572-476: The earliest 300 bit/s modems. When new commands were required to control additional functionality in higher speed modems, a variety of one-off standards emerged from each of the major vendors. These continued to share the basic command structure and syntax, but added any number of new commands using some sort of prefix character – & for Hayes and USRobotics , and \ for Microcom , for instance. Many of these were re-standardized on
3648-422: The early 1990s. Slowly, a set of commands based heavily on the original Hayes extended set using & commands became popular, and then universal . Only one other command set has remained popular, the U.S. Robotics set from their popular line of modems. The following text lists part of the Hayes command set, also called the AT commands : "AT" meaning 'attention'. Each command string is prefixed with "AT", and
3724-515: The end of the 19th century differences in standards between companies was making trade increasingly difficult and strained. For instance, in 1895 an iron and steel dealer recorded his displeasure in The Times : "Architects and engineers generally specify such unnecessarily diverse types of sectional material or given work that anything like economical and continuous manufacture becomes impossible. In this country no two professional men are agreed upon
3800-563: The following sectors: The EIA announced in 2007 that it would be dissolved into its constituent divisions, and transferred operations soon after. The Alliance formally ceased to exist on February 11, 2011. EIA designated ECA to continue to develop standards for interconnect, passive and electro-mechanical (IP&E) electronic components under the ANSI-designation of EIA standards. All other electronic components standards will be managed by their respective sectors. The ECA merged with
3876-480: The foreword with a statement like the following: "Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights". If the standards organization is aware that parts of a given standard fall under patent protection, it will often require the patent holder to agree to Reasonable and non-discriminatory licensing before including it in
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#17327865988703952-832: The former sectors continue to serve the constituencies of EIA. In 1924, 50 radio manufacturers in Chicago formed a trade group called the Associated Radio Manufacturers . This organization was designed to control the licensing of the large number of radio patents so that each member could have access to all the relevant patents necessary to build radio transmitters, antennas and receivers. Over time, new electronic technologies brought new members, non-manufacturer members, and name changes. Names in chronological order: The organization's headquarters were in Arlington, Virginia . The EIA divided its activities into
4028-657: The goal of providing transparency and control with regard to technical regulations. Sub-regional standards organizations also exist such as the MERCOSUR Standardization Association (AMN), the CARICOM Regional Organisation for Standards and Quality (CROSQ), and the ASEAN Consultative Committee for Standards and Quality (ACCSQ), EAC East Africa Standards Committee www.eac-quality.net , and
4104-401: The inability of their developers to keep abreast with the technological innovation. As a result, a new class of standards setters appeared on the standardization arena: the industry consortia or standards setting organizations (SSOs), which are also referred to as private standards . Despite having limited financial resources, some of them enjoy truly international acceptance. One example is
4180-444: The introduction of low-cost modems and the idea of a semi-dedicated point-to-point link was no longer appropriate. There were potentially thousands of users who might want to dial any of the other thousands of users, and the only solution at the time was to make the user dial manually. The computer industry needed a way to tell the modem what number to dial through software. The earlier separate dialers had this capability, but only at
4256-461: The modem to command mode. The normal escape sequence is three plus signs ("+++"), and to disambiguate it from possible real data, a guard timer is used: it must be preceded by a pause, not have any pauses between the plus signs, and be followed by a pause; by default, a "pause" is one second and "no pause" is anything less. The following syntactical definitions apply: A string can contain many Hayes commands placed together, so as to optimally prepare
4332-468: The modem to dial out or answer, e.g. AT&F &D2 &C1S0=0X4 . Most modem software supported a user supplied initialization string , which was typically a long concatenated AT command which was sent to the modem upon launch. The V.250 specification requires all DCEs to accept a body (after "AT") of at least 40 characters of concatenated commands. The following represents two computers, computer A and computer B, both with modems attached, and
4408-469: The national committee to the IEC of an economy may also be the ISO member from that country or economy. ISO and IEC are private international organizations that are not established by any international treaty. Their members may be non-governmental organizations or governmental agencies, as selected by ISO and IEC (which are privately established organizations). The ITU is a treaty-based organization established as
4484-472: The principle of one member per country. Rather, membership in such organizations is open to those interested in joining and willing to agree to the organization's by-laws – having either organizational/corporate or individual technical experts as members. The Airlines Electronic Engineering Committee (AEEC) was formed in 1949 to prepare avionics system engineering standards with other aviation organizations RTCA, EUROCAE, and ICAO. The standards are widely known as
4560-790: The purpose of safety or for consumer protection act from deceitful practices. The term formal standard refers specifically to a specification that has been approved by a standards setting organization. The term de jure standard refers to a standard mandated by legal requirements or refers generally to any formal standard. In contrast, the term de facto standard refers to a specification (or protocol or technology) that has achieved widespread use and acceptance – often without being approved by any standards organization (or receiving such approval only after it already has achieved widespread use). Examples of de facto standards that were not approved by any standards organizations (or at least not approved until after they were in widespread de facto use) include
4636-495: The purposes given in the standard. It also must implement any command beginning with the plus sign, "+" followed by any letter A to Z, only in accordance with ITU recommendations. Modem manufacturers are free to implement other commands and S-registers as they see fit, and may add options to standard commands. The ETSI GSM 07.07 (3GPP TS 27.007) specifies AT style commands for controlling a GSM phone or modem. The ETSI GSM 07.05 (3GPP TS 27.005) specifies AT style commands for managing
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#17327865988704712-448: The same with Company C's sphygmomanometer as it does with Company D's, or that all shirts that should not be ironed have the same icon (a clothes iron crossed out with an X) on the label. Most standards are voluntary in the sense that they are offered for adoption by people or industry without being mandated in law. Some standards become mandatory when they are adopted by regulators as legal requirements in particular domains, often for
4788-469: The second dial tone R – Reverse to answer-mode after dialing @ - Wait for up to 30 seconds for one or more ringbacks , - Pause for the time specified in register S8 (usually 2 seconds) ; – Remain in command mode after dialing. ! – Flash switch-hook (Hang up for a half second, as in transferring a call.) L – Dial last number Note that S n , ? and = r are actually three separate commands, and can be given in separate AT commands. Note:
4864-610: The size and weight of a girder to employ for given work". The Engineering Standards Committee was established in London in 1901 as the world's first national standards body. It subsequently extended its standardization work and became the British Engineering Standards Association in 1918, adopting the name British Standards Institution in 1931 after receiving its Royal Charter in 1929. The national standards were adopted universally throughout
4940-454: The standard. Such an agreement is regarded as a legally binding contract, as in the 2012 case Microsoft v. Motorola . The ever-quickening pace of technology evolution is now more than ever affecting the way new standards are proposed, developed and implemented. Since traditional, widely respected standards organizations tend to operate at a slower pace than technology evolves, many standards they develop are becoming less relevant because of
5016-455: The standards organization except in the special case when the organization holds patent rights or some other ownership of the intellectual property described in the standard. It is, however, liable for any patent infringement by its implementation, just as with any other implementation of technology. The standards organizations give no guarantees that patents relevant to a given standard have been identified. ISO standards draw attention to this in
5092-510: The standards organizations. The implementation of standards in industry and commerce became highly important with the onset of the Industrial Revolution and the need for high-precision machine tools and interchangeable parts . Henry Maudslay developed the first industrially practical screw-cutting lathe in 1800, which allowed for the standardization of screw thread sizes for the first time. Maudslay's work, as well as
5168-554: The two. For example, the Standards Council of Canada is a Canadian Crown Corporation , Dirección General de Normas is a governmental agency within the Mexican Ministry of Economy, and ANSI is a 501(c)(3) non-profit U.S. organization with members from both the private and public sectors. The National Institute of Standards and Technology (NIST), the U.S. government's standards agency, cooperates with ANSI under
5244-1102: The use of other published standards internationally). There are many international standards organizations. The three largest and most well-established such organizations are the International Organization for Standardization (ISO), the International Electrotechnical Commission (IEC), and the International Telecommunication Union (ITU), which have each existed for more than 50 years (founded in 1947, 1906, and 1865, respectively) and are all based in Geneva , Switzerland . They have established tens of thousands of standards covering almost every conceivable topic. Many of these are then adopted worldwide replacing various incompatible "homegrown" standards. Many of these standards are naturally evolved from those designed in-house within an industry, or by
5320-408: The user controlling the modems with terminal emulator software. Terminal-emulator software typically allows the user to send Hayes commands directly to the modem, and to see the responses. In this example, the user of computer A makes the modem dial the phone number of modem B at phone number (212) 555-0100 (long distance). After every command and response, there is a carriage return sent to complete
5396-408: The user of the computer ever tried to send an e-mail containing the aforementioned string. The Hayes command set includes commands for various phone-line operations such as dialing and hanging-up. It also includes various controls to set up the modem, including a set of register commands which allowed the user to directly set the various memory locations in the original Hayes modem. The command set
5472-400: The user placing the call would switch their modem to "originate" and then dial the number by hand. When the remote modem answered, already set to "answer" mode, the telephone handset was switched off and communications continued until the caller manually disconnected. When automation was required, it was commonly only needed on the answer side; for instance, a bank might need to take calls from
5548-415: The user with some option whereby they could enter whatever special commands it took to coerce their particular modem into acting properly. The Hayes command set facilitated automatic baud rate detection as "A" and "T" happen to have bit patterns that are very regular; "A" is "100 0001" and so has a 1 bit at the start and end and "T" is "101 0100" which has a pattern with (nearly) every other bit set. Since
5624-423: Was copied largely verbatim, including the meaning of the registers, by almost all early 300 baud modem manufacturers, of which there were quite a few. The expansion to 1200 and 2400 baud required the addition of new commands, some of them prefixed with an ampersand ( & ) to denote those dedicated to new functionality. Hayes itself was forced to quickly introduce a 2400 baud model shortly after their 1200, and
5700-419: Was slow to release modems supporting higher speeds or compression , and three other companies led: Microcom , U.S. Robotics , and Telebit . Each of these three used its own additional command-sets. By the early-1990s, there were four major command sets in use, and a number of versions based on one of these. Things became simpler again during the widespread introduction of 14.4 and 28.8 kbit/s modems in
5776-406: Was so well received that he was asked to look into the formation of a commission to oversee the process. By 1906, his work was complete and he drew up a permanent terms for the International Electrotechnical Commission . The body held its first meeting that year in London, with representatives from 14 countries. In honour of his contribution to electrical standardization, Lord Kelvin was elected as
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