[GreenKeys] Seeking Info for Beginner

[Harold Hallikainen]

Welcome to RTTY!

I have a LITTLE experience with the model 28, but started with the 15 a
little over 50 years ago and am currently operating one (see
https://w6iwi.org/rtty ). So, I might be able to help with that one.

Can you tell us what equipment you have?

I understand you have a model 15 with a keyboard (KSR). And, I guess the
28 does not have punched tape equipment. That was an option.

I'm using the model 15KSR, a 14 typing reperforator, and a 14 transmitter
distributor (tape reader).

On the 15, what wire currently attach to the unit besides the power cord?
The 15 and 28 can be electrically very simple. However, with all the
options available, they can get complicated. In their simple form, there
would be 6 wires leaving the unit (or maybe 6). Two (or three) wires for
motor power (hot, neutral, and safety ground). Two wires for the selector
magnet on the typing unit. Two wires for the keyboard.

The Teletypes work on a current loop. It is usually 60 mA (though 20 mA is
possible with series connected "pulling" magnets). To set up a local loop,
connect the keyboard in series with the selector magnet, a 2k 10 watt
resistor, and a 120V DC power supply (again, see my notes at
https://w6iwi.org/rtty ). You should then be able to type on the keyboard
and have it show up on the typing unit.

Do you have a "terminal unit?" A TU is a modem for radioteletype. It
generates tones to drive the transmitter and receives tones and converts
them to on/off keying of the Teletype loop. If you have a TU, it probably
has a loop supply in it.

So, there's a start! Please send more questions.

Harold
https://w6iwi.org




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