[GreenKeys] TTY Speeds

[greenkeys@mailman.qth.net]

When you say the AP ran at 66 WPM, does that mean 50 baud?  Or 45.45 baud
with 7.0 unit code?  Either of which gives about 66 WPM.

As long ago as 1938 the standard speeds were approximately 40, 60, and
75 WPM in the Bell System. (Source AT&T Green Book, "Principles of
Electricity..." 1938 edition.)  That would mean Model 14 and 15 equipment,
since the 28 did not yet exist.  During World War II there was some
operation at 100 WPM, where it was felt the urgent need for traffic
carrying capacity outweighed the high maintenance requirement.
(Source, Bell Laboratories Record, April 1948, p 165.)

In the late 1950s I saw a Model 15 operating experimentally at 100 WPM at
the FAA center in Oklahoma City.  They wisely gave up on that and decided
to replace their machines with Model 28s.

The XD transmitter-distributor had no trouble running at 100 WPM.  The
late model ones were fitted with Model 28-style clutches replacing the
felt friction clutches for better operation at 100 WPM.