[GreenKeys] Teletype on 4.004 Revisted

[Jim Haynes]

My understanding is that modern crypto equipment emits a continuous stream
of random-looking bits and they keep it up regardless of whether there
is traffic, so as to foil traffic analysis.

When the transmission starts at precisely 5PM it may be running in
parallel with transmission on another frequency used during the daytime,
so the receiver can switch frequencies without a break in traffic.

jhhaynes at earthlink dot net