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IBM 270x

1960s-era IBM mainframe communication controllers

Summary

1960s-era IBM mainframe communication controllers

Field	Value
name	IBM 270x series
successor	IBM 37xx series
logo_size	120px
image_size	270px
type	Communication controllers
release_date
logo	File:IBM Logo 1956 1972.svg

The family consisted of the following devices:

IBM 2701 Data Adapter Unit
IBM 2702 Transmission Control
IBM 2703 Transmission Control

The 2701 and 2702 were announced simultaneously with System/360 in 1964, the 2703 was announced a year later.

The 270x series was superseded by the IBM 3704 and 3705 communications controllers in 1972.

2701

The 2701 supported up to four start-stop or synchronous communications lines. It had two multiplexor channel interfaces for connection to one or two host computers. The synchronous adapter originally supported the Synchronous Transmit-Receive (STR) protocol, and later Binary Synchronous Communications (BISYNC) when it was introduced in 1967,

Initially the 2701 supported the following devices:

IBM 1009 Data Transmission Unit
IBM 1013 Card Transmission Terminal
IBM 7701 Magnetic Tape Transmission Terminal
IBM 7702 Magnetic Tape Transmission Terminal
IBM 7710 Data Communication Unit
IBM 7711 Data Communication Unit
IBM 7740 Communication Control System
IBM 7750 Programmed Transmission Control
Remote System/360 with 2701
Serial synchronous terminals
IBM 1030 Data Collection System
IBM 1050 Data Communication System
IBM 1060 Data Communication System
IBM 1070 Process Communication System
AT&T 83B2 Type Selective Calling Terminals
Western Union Plan 115A Outstations
Common Carrier TWX Stations
European Teleprinters
Parallel data devices
Contact sense terminals
Contact operate terminals

Later the IBM 2740 and IBM 2741 Communication Terminals, and the IBM 2260/2848 were added.

2702

The 2702 could accommodate up to 31 communication lines, but at a slower speed than the 2701.

Initially the 2702 supported the following terminals:

IBM 1030 Data Collection System
IBM 1050 Data Communication System
IBM 1060 Data Communication System
IBM 1070 Process Communication System
AT&T 83B2 Type Selective Calling Terminals
Western Union Plan 115A Outstations
Common Carrier TWX Stations
European Teleprinters

Later the IBM 2740 and IBM 2741 Communication Terminals, the IBM 1032 Digital Time Unit, and a second channel interface were added.

2703

The 2703 supported up to 176 half-duplex start-stop or Binary Synchronous communication lines. The maximum speed of one line was 2400 bit/s but the total aggregate line speed was limited. By 1970 the maximum line speed had been raised to 4800 bit/s. The 2703 attached to a single multiplexer channel; each communication line occupied a subchannel. It had a four or eight byte buffer per line to reduce data transfer to and from the host computer. The IBM 2712 Remote Multiplexer allowed up to fourteen slow speed devices to be multiplexed over one high speed line to a 2703.

As of 1967 the 2703 supported the following devices:

IBM 1030 Data Collection System
IBM 1050 Data Communication System
IBM 1060 Data Communication System
IBM 1070 Process Communication System
IBM 2741 and 2740 Communications Terminals
AT&T 83B2 Type Selective Calling Terminals
Western Union Plan 115A Outstations
Common Carrier TWX Stations
Remote System/360 via 2701 with 2701 or 2703
IBM 2780 Data Transmission Terminal
IBM 1130 Computing System with Synchronous Communications Adapter (SCA)

Clones

Many companies produced clones of 270x controllers, such as the Memorex 1270, introduced in 1970, and devices from NCR-Comten.

References

(1991). "IBM's 360 and Early 370 Systems". MIT Press.
IBM Corporation. (1965). "IBM 2701 Data Adapter Unit Principles of Operation".
IBM Corporation. (1967). "IBM 2703 Transmission Control Component Description".

Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

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