Our intent is to capture technical information for equipment that is no longer supported by the manufacturer in either service or documentation. As additional material is scanned and prepared, new entries will be added to these archives. Content is presented in HTML where practical and Adobe PDF format for schematics, wiring diagrams, and manuals.

Original content copyright © 2011 William Bytheway K7TTY and George Hutchison W7TTY. Site maintained by W2TTY.

Much of the technical content in the Teletype Machines section — particularly for the Mainline series of demodulators — was written by Irvin M. Hoff, variously W6FFC and K8DKG, who designed the TT/L, ST-3, ST-5, ST-6, and UT-2 demodulators and documented them in the RTTY Journal and QST over many years. His Introduction to Amateur Radio Teletype, written for Frederick Electronics Corporation, remains one of the clearest primers on the subject. Content is reproduced here for archival and reference purposes.

Wiring diagrams, schematics, and military technical manuals are reproduced from official publications for historical reference. War Department and Teletype Corporation materials are believed to be in the public domain. Bell System Practices documents are reproduced for historical preservation purposes.