Bell System Dataphone 9600  
Written by Accutron on 2017-04-21  

The Dataphone 9600 is a high speed synchronous modem introduced by AT&T in 1975. As implied by its name, the maximum data rate of the Dataphone 9600 is 9600 baud, the fastest long-distance wired data rate possible in the mid-1970s. The Dataphone 9600 can operate in one of five multiplexing modes, ranging from one 9600 baud channel to four 2400 baud channels. The Dataphone 9600 weighs approximately 20kg, with a heavy aluminum chassis and card cage construction with a hand-wired backplane. At the time of its introduction, the Dataphone 9600 could only be used on phone lines specially conditioned for high speed data transfer.

The Dataphone 9600 has the dubious distinction of being the only modem known to have killed a person. In 1983, Nelly Doris Medina, an employee of the New York Telephone Company, was exposed to dimethylformamimide (DMF) when a Sangamo Weston capacitor in a Dataphone 9600 modem failed. Medina, eight months pregnant at the time, was exposed to DMF venting from the capacitor over a 10-day period, and subsequently died from complications due to toxemia.

Bell System Dataphone 9600 Advertisement (PDF)

Bell System Dataphone 9600 high speed synchronous modem.

Dataphone 9600 card cage, populated with 21 circuit cards. The Dataphone 9600 includes over 500 SSI ICs, a complexity comparable to an early minicomputer.

Dataphone 9600 circuit cards KD3 and KD19B.

Dataphone 9600 circuit card KD18B. Note the array of Western Electric 530A LED indicators.

Dataphone 9600, rear connections and backplane wiring.

This article is part of the [Digital Computer Equipment] exhibit.

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