[GreenKeys] ASR 33

[George B. Hutchison]

Mr. Elmore - - -

Your model 33ASR is not directly compatible with RTTY

Standard RTTY as found in the amatuer bands employs a 5 unit 
start-stop code, while the 33ASR is built for an 8 unit code.

Standard RTTY runs at 60 words per minute, and your ASR is geared for 
100. Installing 60 speed gears in your ASR would not work. 60 speed 
gears for that model series are so difficult to obtain that one of 
the members on the GreenKeys list made his own.

It is possible to find software conversions so that 60 WPM RTTY can 
be converted to 100 WPM ASCII.  A very simple circuit can be made 
that will convert the RS-232 output levels found on earler PCs can be 
converted to to the 20 milliampere series loop circuit that is common 
to the model 33 machines. It is also possible that your machine is 
equipped with an RS-232 driver such that no signel level conversion 
is needed.

If you are truly interested in copying RTTY as found on the amateur 
radio bands I suggest you consider the following:

Put your model 33 up for sale on ebay. If the machine is in 
reasonably good condition Model 33s have been known to sell for 
ungodly prices, 300-400 dollars on ebay.

After you have sold your 33 look around for one of the most commonly 
available teletype machines such as an older model 15, or else 
perhaps a model 28, both of which appear fairly regularly on ebay.

You might also inquire on the GreenKeys reflector whether ot not one 
of the enthusiasts might have a machine available for a good home. 
Most of them available in this sector are geared for 60, or gears can 
be had for the aasking.

One enthusuast recently gave away a pile of machines because he is 
moving to Brooklyn, and did not want the thugs and pimps  to set up a 
"Losers Teletype Network" after all of his machines were stolen. (A 
little tongue-in-cheek humor, there)

The previous note from Mr. Alderdice I believe reinforces the 
compatibility issue, and my missive gives you some options.

Be sure to hang on to your ST-6. That has become a mainstay for many, 
and the durability of the design could not be foretold back when it 
was conceived.

Hope this helps.

Good Luck,

George - W7TTY