[GreenKeys] Parallel TTY

[Nick England]

There’s an interesting NSA crypto history document at
https://www.archives.gov/files/declassification/iscap/pdf/2009-049-doc1.pdf

In lecture 10 on TEMPEST, there is discussion of attempts to reduce
emissions from TTY gear. One attempt was to make all the bits change at the
same time and another involved 10 wires (differential signaling I presume).

Model 28 parallel signal (multiple contact) tape reader units are pretty
well known (LBXD for example), but I haven’t ever seen a M28 parallel
signal keyboard except for the Compact KSR which has a M32 keyboard.

Of course it may just have been a back room prototype or ???

Cheers
Nick
-- 
Nick England K4NYW
www.navy-radio.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20210401/2474907f/attachment.html>