[GreenKeys] TTY driver software?

[Ralph Mowery]

The mmtty program will key an old timey printer port.  You will need to shift the level from the low voltage to a higher voltage loop.

 

The audio demodulators , even the simple ones , work just fine for the low speed of the teletype machines if the audio is clean like from a computer and not off the radio.

 

If you cobble together what is called a st-5 from two ICs and a couple of torrords and a keying transistor and feed it with audio the machine will be just fine.

 

73 de Ralph KU4PT

 

 

From: greenkeys-bounces at mailman.qth.net [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of hwhall at compuserve.com
Sent: Tuesday, April 10, 2018 9:31 PM
To: GreenKeys at mailman.qth.net
Subject: Re: [GreenKeys] TTY driver software?

 

I'm the person who started the thread, and throwing together a circuit is not a problem.  I'm rummaging around now to see what old PC I can resurrect to run the teletype testing with, but another old radio project has been handed to me for restoration, so I may not make a lot of headway with the teletype for a bit.

It was my assumption that it would be easier to find a program that would key an output line instead of a program that would output RTTY tones.  Perhaps that was incorrect?  I was also thinking a nice squared up switching signal would be one less "iffy" thing to wonder about when observing the teletype while running a test.  And maybe a tone demodulator is more reliable than I worried about.

 

Wayne
WB4OGM 

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