Bell 101

The Bell 101 Data Set was the first commercial modem for computers, released by AT&T Corporation in 1958 for use by SAGE, and made commercially available in 1959, shortly after AT&T's Bell Labs announced their 110 baud modulation frequencies.

[1][2] The Bell 101 allowed digital data to be transmitted over regular unconditioned telephone lines at a speed of 110 bits per second.

The Bell 101 modem used audio frequency-shift keying to encode data.

Different pairs of audio frequencies were used by each station:[3] Bell 101 modems are no longer in use and were quickly replaced by its successor the Bell 103 modem.

This article related to telecommunications is a stub.

The back of a Teletype Model 33 teleprinter with a Bell 101C Data Set in the pedestal, 1963.