[RTTY] Zone sent as letters?

[Kok Chen]

On Sep 27, 2009, at 9/27    8:50 AM, Jim W7RY wrote:

> USOS does not effect transmitting?

Unfortunately, it does.

The transmitter has to check if a character with a numerical shift is  
being send right after sending a space character.  When USOS is used  
at the receiving end, the transmitter is responsible for sending an  
additional Baudot FIGS character between that space and the following  
numeric.

The transmitter has to assume that the USOS receiver has shifted  
itself into the LTRS shift when the receiver saw the space.

With Baudot, the space character occupies both the LTRS shift and the  
FIGS shift partitions of the code table.  So the normal way of sending  
"599 03" is to simply send "599<space>03" and be done with it.

However, if the receiver is known to be using USOS, the transmitter  
has to alter the character sequence to "599<space><FIGS>03" for the  
"03" part to print correctly at the other end.

73
Chen, W7AY