[GreenKeys] CRLF or not CRLF?

[PJ Bennett]

Good info, thanks!  

One question though, since an ASR33 needs a converter (RTTY baudot to
ASCII), would using an ASR33 then not qualify for this special category?

_____________________________________
 PJ Bennett, BSEE
 918.704.7055 | pj at pjbennett.com | pjbennett.com



-----Original Message-----
From: greenkeys-bounces at mailman.qth.net
[mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Jeffrey Angus
Sent: Sunday, July 30, 2017 12:18 AM
To: greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] CRLF or not CRLF?

Ok, let me try this again.

RTTY is two tones. Either sent AFSK detected directly, or FSK detected with
a BFO resulting in two audio tones.
These in turn go through a terminal unit that decodes the two tones into
direct keying Mark (on) and Space (off).
This keyed signal, hopefully close to the original transmitted signal, is
fed directly to a mechanical decoder/printer.
Teletype, Kleinschmidt, Mite, Lorenz, Creed and such.
The machines decode the signal keying directly.
The terminal units themselves do not decode the signal into characters.

The CV-89, Twin City TU, HAL ST-6, ST-6000, MFJ 1224 and Dovetrons are
terminal units. They convert RTTY signals from a radio receiver to a keyed
local loop that is connected to a Teletype machine. That is ALL that they
do. An exception is the HAL ST-8000A that does not have a keyed current loop
output but has low lever signals instead, but it still just a mirror of the
two tones fed into it.

Things like the MFJ 1289, Kantronics KAM and AEA PK-232 are not terminal
units.
They are decoders, they have to be told what they are decoding. ASCII or
Baudot, and what speed, 60, 66, 75, 100, 110 WPM etc. and their output is an
ASCII 8-level code regardless of what the input signal is. A 5-level Baudot
two-tone signal input is output as an 8-level ASCII signal at either RS-232
or TTL signal levels.

It was my impression that the whole idea of having a "special category" 
for those that
run mechanical machines is that the machines are doing the decoding. And not
the use of a decoder and using the machine as a "dumb terminal."




-- 
Jeff-1.0
www.foxsmercantile.com

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