Bell 202
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The Bell 202 modem was an early modem standard developed by the Bell System. It specifies audio frequency-shift keying to encode and transfer data at a rate of 1200 bits per second, half-duplex. It ha
The DEC DF112 from the mid-1980s used the Bell 202 protocol.
Duplex (telecommunications)
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A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in m
Bell 202
…developed by the Bell System. It specifies audio frequency-shift keying (AFSK) to encode and transfer data at a rate of 1200 bits per second (bit/s), half-duplex. It has separate sets of circuits for 1200 bit/s and 300 bit/s rates. These signalling protocols, also used in third-party modems, are referred to…
Simplex wireless communication
A simple illustration of a half-duplex communication system