RS-232
Tape Data Recovery - RS-232
Recommended Standard 232 (RS-232) is a standard issued by the Electronics Industries Association (EIA) to be used in asynchronous serial communication methods such as computer serial ports. In serial communication methods, the information is sent one bit at a time. In asynchronous communication, information is not sent in predefined time slots.
Originally the standard was applicable to DTEs such as electromechanical teletypewriters and DCEs such as modems. Later electronic terminals emerged, and they were often designed to be interchangeable with teletypes, and so supported RS-232. The C revision of the standard was issued in 1969 with an aim to accommodate the electrical characteristics of these devices.
EIA standard RS-232-C defines Electrical signal characteristics such as voltage levels, signaling rate, timing and slew-rate of signals, voltage withstand level, short-circuit behavior, and maximum load capacitance; interface mechanical characteristics, pluggable connectors and pin identification; functions of each circuit in the interface connector; and standard subsets of interface circuits for selected telecom applications.
The standard does not define elements such as character encoding, framing of characters in the data stream, protocols for error detection or algorithms for data compression, bit rates for transmission, and power supply to external devices.
Since the applications of RS-232 have extended far beyond the original purpose of interconnecting a terminal with a modem, succeeding standards have been developed to address these limitations. In personal computing industry, RS-232 is being replaced by USB for local communications.
