Teletype repairmen and data communications professionals almost always carried pocket and wallet reference cards listing the codes, character positions, and signal parameters for the machines they serviced. They were issued by manufacturers, telephone companies, and training programs — often trade-show giveaways or badges of honor from technical schools. The collection below preserves a sample of these cards. Contributions are welcome; contact W2TTY.

A note on code variants: the five-unit code used by all these machines is ITA2 (International Telegraph Alphabet No. 2), but ITA2 left several figures-shift positions open for national assignment. The Teletype Corporation cards in this collection — the Model 28, the 50th Anniversary card, the TypeBox charts — use the American assignment, known as the Teletypewriter Code or USTTY. Its signatures are ! on the F-key and the bell on the S-key. International cards (the UK Post Office and Telecom Australia entries below) use their respective national arrangements, where % occupies the F-key and the bell is on J. The bits transmitted are identical; what appears on paper depends on the receiving machine’s type basket. More on ITA2 and USTTY →

Copyright © George Hutchison W7TTY & Bill Bytheway K7TTY. All rights reserved.