Jomar,

Any AFSK converter (aka "Terminal Unit") made for amateur radio will work, eg. HAL, Dovetron, Flesher, etc and most will include the loop supply. (Older tube type and military units may only do 850 Hz shift; ITTY is 170 Hz shift.)

You can build a simple AFSK demodulator with a 2211 chip and an optocoupler interface - schematic enclosed.

Loop supply just needs 100-150 VDC source that can supply 60ma; plus a current limiting resistor. No regulation is required. Often old teletype supplies can be found, but they may contain selenium rectifiers which should be replaced with silicon rectifiers. (Selenium can put off poisonous gas when abused)

Good luck & Have fun,

Duncan
K2OEQ

On 6/30/2024 10:05 PM, Jomar Quilatan wrote:

Hi all,

So after a partial restoration of my model 26 (mostly cleaning and de-gunking), I've been able to get it to at least code keyboard inputs correctly (after giving it a moment to warm up...still will gradually free up all the related parts) and fixed a carriage return issue simply by increasing tension (thanks to a fellow person on this forum for suggesting that fix).

Now I'm on to the next part - getting stuff to be sent to my unit.

Is there a rudimentary assembly that can be put together or bought to interface external text sources, ITTY, etc with the Teletype (similar to my temporary workaround of a 9V battery as my loop current), or is this where having amateur radio gear / knowledge will come in (aka the sky's the limit)? In other words, what could be the next natural step to take with this machine?

Looking forward to your input.

Regards,

Jomar (Joshua Martin) Quilatan

Mississauga (Toronto), Canada

RA 0-8045
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