On Jul 6, 2009, at 7/6 10:26 AM, Bill, W6WRT wrote:
> As to the hyphen, my preference is to not use it at all. The
> presence of the
> hyphen defeats the USOS function, although it does speed up the
> transmission a
> small amount.
The reason a hyphen instead of a space delimiter is a good idea is to
allow compatibility between USOS and non-USOS machines.
(Sending shorter streams not only saves the time to transmit an
exchange, but more importantly also reduce extra errors that confuses
the reader. The same is true for example when you use lower case
characters in PSK31 or DominoEX: not only is lower case faster, lower
case also produces fewer errors.)
------
Example 1: transmitting numbers only exchanges such as "599 123"
A non-USOS transmitter will send "599<space>123" which a USOS receiver
will receive as "599 QWE". (What Rick originally saw.)
If you instead use "599-123", both non-USOS and USOS transmitters will
send "599-123" and both USOS and non-USOS decoders will decode into
599-123.
------
Example 2: transmitting mixed number and alphabet exchanges such as
"599 OR"
Strict USOS transmitters will send "599<space>OR" (instead of
"599<space><ltrs>OR") which a non-USOS receiver will receive as "599
94". (We have complains of that after every Roundup, it seems :-).
Again, if you use "599-OR" both the USOS and non-USOS transmitter will
send it as "599-<ltrs>OR". And both USOS and non-USOS decoders will
decode it into "599-OR".
------
Even if you don't like the looks of a dash in between your exchanges,
it is probably a good idea to include it in the set of macros which
are at your fingertips for the instances where you are asked over and
over for a repeat.
That being said, there are software that allow you to insert an
explicit <FIGS> or <LTRS> into the Baudot stream. And there are
software that can default to sending a <LTRS> character after a space
even when USOS is turned on.
And there is one program that allows you to set a preference to
periodically add LTRS in between long strings of alphabets, and FIGS
between long strings of numbers (what it calls the "robust" mode).
Some programs allow you to print the "raw" output (i.e., usually non-
printing characters such as CR, LF, LTRS and FIGS will also appear on
the screen as <cr>, <lf>, <ltrs> and <figs>). Turn it on, and you can
see a pretty wide variety of encodings. For example, some programs
sends CR/LF for a newline, while other programs send only CR or LF for
a newline (much to the dismay of people who still using mechanical
teletypes). And for USOS, some will not send a LTRS after a space if
what follows a space is an alphabet, others will.
73
Chen, W7AY
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