[GreenKeys] Unshift on space (was Re: Christmas Music)

[Jim Haynes]

Was something of a controversial feature in the early days of RTTY.
Lots of magazine articles tell you how to disable it if you machine
has it, and advocating disabling it because not all machines have it.

I took an opposite view, that USOS is valuable in radio work because
you are frequently getting false FIGS shifts or missing LTRS shifts
and USOS will get the machine back into LTRS case where it belongs
most of the time.  But you have to transmit with the assumption that
the other guy's machine doesn't have the feature, so always send a LTRS
when you want to go to LTRS; don't rely on a space doing it for you.

In my limited experience the only professional use of machines with
USOS disabled was in weather service, where certain transmissions
consist of many lines of nothing but digits, so keeping USOS disabled
avoids having to insert a FIGS character after every space.

I believe by the latter days of amateur RTTY with machines just about
everybody had a machine that would do USOS and the advice to disable
the feature was generally ignored.

jhhaynes at earthlink dot net