RTTY with regular modem?

RTTY with regular modem?

Post by Charles Copela » Mon, 09 May 1994 10:31:53



Quote:>Is there a way to read RTTY with a regular phone modem?

I know UARTS (8250,16550) both support 5 bit ASCII (baudot), but
don't know what modulation technique RTTY uses.

Can this be done?
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RTTY with regular modem?

Post by John Lundgr » Mon, 09 May 1994 23:57:10


No.  RTTY is narrow band FSK.  Modems don't do that narrow a band,
but use as much of the the full 300 to 3700 Hz bandwidth as they can.  
They actually put out an audio carrier.  What you want to do is shift
your RF carrier with the RTTY signal.  So the RTTY pulses would be fed
into the transmitter oscillator or VCO.  If you have an RTTY, it probably
puts out current loop, and most modems don't handle current loop.