Re: [RTTY] Unshifted Numbers

[Jerry Flanders <jeflanders@comcast.net>]

There are two different character sets used in RTTY - the letters set and 
the figures set. The machines switch back from one to the other by means of 
a shift "character". For instance, if the figures shift is missed, you see 
TOO instead of 599.

Anybody interested in the Baudot/Murray code can see: 
http://www.dataip.co.uk/Reference/BaudotTable.php
You can see how a single corrupted bit can change a character, and how it 
might print.

It also shows the LETTERS/FIGURES correspondence (how it will print if the 
shift character is missed).

Jerry W4UK

At 22:01 2/14/2005, NB1B wrote:
> Being a relative newbie to RTTY contesting, I made (for me) a startling
> discovery this weekend.
>
> After continually receiving PPQ in response to my "NR? NR?" inquiry, I
> discovered that "PPQ" is the same as "001".   After operating for 24 hours,
> it seems like the following letters equal the numbers:
> P=0
> Q=1
> W=2
> ???=3 (never did figure that one out)
> R=4
> T=5
> Y=6
> U=7
> I=8
> O=9
>
> That "TOO" I see on my screen didn't mean that I also got a "599"- it was
> the "599".
>
> What mechanism makes some programs send the letters instead of the numbers?
> I don't think the problem was on my rx end when someone would send me "TOO
> PPQ PPQ", I'd ask for the number, and he would repeat the same string of
> letters a second time.   What actually clued me in to this was a station
> would send "599 PQP 010", so I'd ask for the number, and he'd send "599 010
> PQP" back.
>
> Dennis NB1B


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