[RTTY] RTTY Screwed by FCC?

[Bill Turner]

ORIGINAL MESSAGE:

On Fri, 13 Oct 2006 20:03:35 -0400, Bill Coleman <aa4lr at arrl.net>
 wrote:

>RTTY is digital.

------------ REPLY FOLLOWS ------------

No, RTTY is a binary (two state) mode, but it is not digital, any more
than CW is. People have fallen into the trap of thinking that because
a signal has two states, it is digital, but such is not necessarily
the case. For a signal to be digital, the bits have to represent
numbers and in the case of both RTTY and CW, that is not true.

In a digital system the length of a bit is of no consequence, but in
both RTTY and CW, it is. RTTY uses a stop bit that is longer than the
others and that is how the decoder knows it is in fact a stop bit.
With CW, the difference between a dot and dash is crucial, where in a
digital system they would both equal the same number. 

Long before digital computers existed, RTTY was being decoded with an
analog computer known as a teletype machine. No numbers involved.

Bill, W6WRT