Re: RTTY & Linux : Possible ?

[Kai Schulte]

On Tue, 19 Oct 1999, Thomas Sailer wrote:

> Does the hamcomm interface have a demodulator (like the DJ6HP
> filter converter) or is it really just a zero crossing detector?

Yes, it is just an op-amp.  All it does is amplify the input and cut
the output off at rs232 signal levels (it is powered from
the serial interface, one handshake output line clamped high, the
other low).  You receive the resulting pulse through one of
the input handshake lines, so any information about the signal
has to be "guessed" from the lengths of the measured intervals.

It's pretty ridiculous by today's standards, but before sound cards
became cheap it was a very versatile fm-tool indeed (provided you
were dealing whith strong signals).

Kai