Bell 101 modem

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

The Bell 101 modem, or 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. The Bell 101 allowed digital data to be transmitted over regular unconditioned telephone lines at a speed of 110 bits per second.

Bell 101 modems are no longer in use and were quickly replaced by its successor the Bell 103 modem. SAGE modems were described by AT&T's Bell Labs as conforming to the Bell 101 data set standard.

See also

• List of device bandwidths
• Bell 202 modem

Further reading

• Weber, Laurance A. (1959). "A frequency-modulation digital subset for data transmission over telephone lines". Transactions of the American Institute of Electrical Engineers, Part I: Communication and Electronics. 77 (6): 867–872. doi:10.1109/TCE.1959.6372907. S2CID 51673551.
• Soffel, R. O.; Spack, E. G. (1959). "SAGE data terminals". Transactions of the American Institute of Electrical Engineers, Part I: Communication and Electronics. 77 (6): 872–879. doi:10.1109/TCE.1959.6372908. ISSN 0097-2452. S2CID 51676153.
• Data Set 101C: Identification and Operation (PDF). Bell System Practices. AT&T Co. March 1963.
• Kline, Ronald R. (2019). "The Modem that Still Connects Us". Historical Studies in Computing, Information, and Society. History of Computing. pp. 29–50. doi:10.1007/978-3-030-18955-6_3. ISBN 978-3-030-18954-9. S2CID 213434332.