Bell 212A
The Bell 212A modulation scheme defined a standard method of transmitting full-duplex asynchronous or synchronous serial data at 1200 bits per second (bit/s) over analogue transmission lines. The equivalent, but incompatible ITU-T standard is V.22.
Device
[edit]The Bell 212 Dataset is a 1979-vintage modem used for communicating over telephone lines at 300 or 1200 bit/s.[1] The 212A standard provides for the ability of a modem to auto-answer a ringing phone.[2]
Usage
[edit]The Bell 212A scheme was the most common standard used for 1200 bit/s transmission on US data networks such as CompuServe during the 1980s and 1990s, when dial-up access to time-sharing services was the norm, and, starting in 1989, dial-up Internet access.[3][2]
See also
[edit]References
[edit]- ^ "BSP 592-039-100: Data Set 212AR-L1A/2A -- Transmitter-Receiver -- Description and Operation", Bell System Practices, American Telephone & Telegraph Co, June 1979
- ^ a b Frank J. Derfler, "The Universal Data Systems' 212 LP modem", InfoWorld, pp. 52-53, 9 August 1982.
- ^ Frank J. Derfler Jr., "Selecting the right modem", PC Magazine, pp. 224-233, January 1983.
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