Teletype machines from the Teletype Corporation, Skokie, Illinois. Left: The Teletype Corporation ASR 33 Teletype (1967). 110 bps, 8-level ASCII encoding (uppercase only); 4-row Automatic Send Receive, 101C Dataset (modem); Bell System TWX service. Right: ASR33 without built-in telephone: 100% mechanical, no electronics. Regular maintenance and lubrication is required.
The ASR33 (pictured) above was by far the most common Teletype model, although we did have an ASR37 in the machine room for some time (NEED PHOTO). Paper is roll-fed. The paper tape device would be used for sending recorded keysrokes or other data, or it could be used to capture incoming material (thus Automatic Send Receive). The KSR models (Keyboard Send Receive) lacked the paper tape reader/punch. Most non-IBM computers of the 1960s until the mid-1970s -- such as DEC PDP-xx minicomputers -- came with a Teletype console terminal. The 33 and 35 models were uppercase only; the 37 model had upper and lower case.
Pushing the keys was a good exercise; the keys traveled a good half inch before making contact, and resistance was considerable. The Answerback reply was programmed by breaking teeth off a plastic gear. Teletypes in one form or another go back to about 1909. They were used originally as automatic Telegraph and Telegram machines. Teletypes reached their familiar mature form around 1920.
Third Photo: Carl Friend (and also correct identification of the Model 37). Other photos: found on the Web.
CLICK HERE for a large color photo from the Catholic University of Leeuwen. For a detailed history of the Teletype, CLICK HERE.
