Telecommunication control unit

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A telecommunication control unit (TCU), line control unit, or terminal control unit [1] (although terminal control unit may also refer to a terminal cluster controller) is a Front-end processor for mainframes and some minicomputers which supports attachment of one or more telecommunication lines. [2] TCUs free processors from handling the data coming in and out of RS-232 ports. The TCU can support multiple terminals, sometimes hundreds. Many of these TCUs can support RS-232 when it is required, although there are other serial interfaces as well.

Front-end processor Small computer to which a large mainframe computer delegates input/output or telecommunications functions

A front end processor (FEP), or a communications processor, is a small-sized computer which interfaces to the host computer a number of networks, such as SNA, or a number of peripheral devices, such as terminals, disk units, printers and tape units. Data is transferred between the host computer and the front end processor using a high-speed parallel interface. The front end processor communicates with peripheral devices using slower serial interfaces, usually also through communication networks. The purpose is to off-load from the host computer the work of managing the peripheral devices, transmitting and receiving messages, packet assembly and disassembly, error detection, and error correction. Two examples are the IBM 3705 Communications Controller and the Burroughs Data Communications Processor.

Mainframe computer computers used primarily by corporate and governmental organizations

Mainframe computers or mainframes are computers used primarily by large organizations for critical applications; bulk data processing, such as census, industry and consumer statistics, enterprise resource planning; and transaction processing. They are larger and have more processing power than some other classes of computers: minicomputers, servers, workstations, and personal computers.

Minicomputer class of smaller computers

A minicomputer, or colloquially mini, is a class of smaller computers that was developed in the mid-1960s and sold for much less than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, The New York Times suggested a consensus definition of a minicomputer as a machine costing less than US$25,000, with an input-output device such as a teleprinter and at least four thousand words of memory, that is capable of running programs in a higher level language, such as Fortran or BASIC. The class formed a distinct group with its own software architectures and operating systems. Minis were designed for control, instrumentation, human interaction, and communication switching as distinct from calculation and record keeping. Many were sold indirectly to original equipment manufacturers (OEMs) for final end use application. During the two decade lifetime of the minicomputer class (1965–1985), almost 100 companies formed and only a half dozen remained.

The advent of ubiquitous TCP/IP has reduced the need for telecommunications control units.

See also

A terminal access controller (TAC) is a host computer that accepts terminal connections, usually from dial-up lines, and that allows the user to invoke Internet remote log-on procedures, such as Telnet.

270x is a generic name for a family of IBM non-programmable communications controllers used with System/360 and System/370 computers.

IBM 3705 Communications Controller IBM mainframe communications controller announced in March 1972

The IBM 3705 Communications Controller is a simple computer which attaches to an IBM System/360 or System/370. Its purpose is to connect communication lines to the mainframe channel. It was a first communications controller of the popular IBM 37xx series. It was announced in March 1972. Designed for semiconductor memory which was not ready at the time of announcement, the 3705-I had to use 1.2 microsecond core storage; the later 3705-II uses 1.0 microsecond SRAM. Monolithic System Technology components, similar to those in S/370, were used.

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IBM 3270 family of block-oriented computer terminals introduced by IBM in 1971

The IBM 3270 is a class of block oriented computer terminals introduced by IBM in 1971 normally used to communicate with IBM mainframes. The 3270 was the successor to the IBM 2260 display terminal. Due to the text colour on the original models, these terminals are informally known as green screen terminals. Unlike a character-oriented terminal, the 3270 minimizes the number of I/O interrupts required by transferring large blocks of data known as data streams, and uses a high speed proprietary communications interface, using coaxial cable.

In telecommunications, RS-232, Recommended Standard 232 is a standard introduced in 1960 for serial communication transmission of data. It formally defines the signals connecting between a DTE such as a computer terminal, and a DCE, such as a modem. The RS-232 standard had been commonly used in computer serial ports. The standard defines the electrical characteristics and timing of signals, the meaning of signals, and the physical size and pinout of connectors. The current version of the standard is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange, issued in 1997.

In telecommunication a data link is the means of connecting one location to another for the purpose of transmitting and receiving digital information. It can also refer to a set of electronics assemblies, consisting of a transmitter and a receiver and the interconnecting data telecommunication circuit. These are governed by a link protocol enabling digital data to be transferred from a data source to a data sink.

Data terminal equipment

Data terminal equipment (DTE) is an end instrument that converts user information into signals or reconverts received signals. These can also be called tail circuits. A DTE device communicates with the data circuit-terminating equipment (DCE). The DTE/DCE classification was introduced by IBM.

A universal asynchronous receiver-transmitter is a computer hardware device for asynchronous serial communication in which the data format and transmission speeds are configurable. The electric signaling levels and methods are handled by a driver circuit external to the UART. A UART is usually an individual integrated circuit (IC) used for serial communications over a computer or peripheral device serial port. One or more UART peripherals are commonly integrated in microcontroller chips. A related device, the universal synchronous and asynchronous receiver-transmitter (USART) also supports synchronous operation.

Systems Network Architecture (SNA) is IBM's proprietary networking architecture, created in 1974. It is a complete protocol stack for interconnecting computers and their resources. SNA describes formats and protocols and is, in itself, not a piece of software. The implementation of SNA takes the form of various communications packages, most notably Virtual Telecommunications Access Method (VTAM), the mainframe software package for SNA communications.

IBM Series/1

The IBM Series/1 is a 16-bit minicomputer, introduced in 1976, that in many respects competed with other minicomputers of the time, such as the PDP-11 from Digital Equipment Corporation and similar offerings from Data General and HP. The Series/1 was typically used to control and operate external electro-mechanical components while also allowing for primitive data storage and handling.

Computer terminal computer input/output device; an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system

A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying or printing data from, a computer or a computing system. The teletype was an example of an early day hardcopy terminal, and predated the use of a computer screen by decades.

The IBM 3790 Communications System, developed by IBM's Data Processing Division (DPD), was announced in 1975. It was one of the first distributed computing platforms. The 3790 preceded the IBM 8100, announced in 1979.

RS-485, also known as TIA-485(-A), EIA-485, is a standard defining the electrical characteristics of drivers and receivers for use in serial communications systems. Electrical signaling is balanced, and multipoint systems are supported. The standard is jointly published by the Telecommunications Industry Association and Electronic Industries Alliance (TIA/EIA). Digital communications networks implementing the standard can be used effectively over long distances and in electrically noisy environments. Multiple receivers may be connected to such a network in a linear, multidrop bus. These characteristics make RS-485 useful in industrial control systems and similar applications.

In computing and especially in computer hardware, a controller is a chip, an expansion card, or a stand-alone device that interfaces with a peripheral device. This may be a link between two parts of a computer or a controller on an external device that manages the operation of that device.

The POWER4 is a microprocessor developed by International Business Machines (IBM) that implemented the 64-bit PowerPC and PowerPC AS instruction set architectures. Released in 2001, the POWER4 succeeded the POWER3 and RS64 microprocessors, and was used in RS/6000 and AS/400 computers, ending a separate development of PowerPC microprocessors for the AS/400. The POWER4 was a multicore microprocessor, with two cores on a single die, the first non-embedded microprocessor to do so. POWER4 Chip was first commercially available multiprocessor chip. The original POWER4 had a clock speed of 1.1 and 1.3 GHz, while an enhanced version, the POWER4+, reached a clock speed of 1.9 GHz. The PowerPC 970 is a derivative of the POWER4.

Pertec Computer Corporation (PCC), formerly Peripheral Equipment Corporation (PEC), was a computer company based in Chatsworth, California which originally designed and manufactured peripherals such as floppy drives, tape drives, instrumentation control and other hardware for computers.

IBM 37xx Series of mainframe communication controllers manufactured by IBM (and clone manufacturers). Essentially a small computer which attached to the mainframe and carried out networking functions on its behalf

IBM 37xx is a family of IBM Systems Network Architecture (SNA) programmable communications controllers used mainly in mainframe environments.

Queued Telecommunications Access Method (QTAM) is an IBM System/360 communications access method incorporating built-in queuing. QTAM was an alternative to the lower level Basic Telecommunications Access Method (BTAM) access method

4690 Operating System, sometimes shortened to 4690 OS or 4690 is a specially designed Point of Sale operating system, originally sold by IBM; however, in 2012 IBM sold its retail business, including this product, to Toshiba, who now supports it. 4690 is widely used by IBM and Toshiba retail customers to drive retail systems running their own applications as well as IBM's Application Client Server Environment (ACE), Supermarket Application (SA), General Sales Application (GSA), and Chain Drug Sales Application (CDSA).

Data Terminal Ready (DTR) is a control signal in RS-232 serial communications, transmitted from data terminal equipment (DTE), such as a computer, to data communications equipment (DCE), for example a modem, to indicate that the terminal is ready for communications and the modem may initiate a communications channel.

References

  1. ↑ System analysis handbook. Fort Benjamin Harrison (Ind.). Computer Science School, United States Army Soldier Support Institute. 1986. p. 3-118. Retrieved July 30, 2016.
  2. ↑ Arick, Martin R. (1987). Data Communications: Concepts & Systems. Wellesley, MA: QED Information Sciences. p. 76. ISBN   9780894351501 . Retrieved July 30, 2016.


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