Re; What to look for in a Model 33 Teletype - a newb's buyer's guide?

tony duell ard at
Fri Nov 21 14:35:29 CST 2014

> Sure, I get all that.. but what on Earth does it have to do with the thread
> topic - which concerns what to look for when acquiring a Model 33 Teletype?

I think we're assuming you are going to connect this ASR33 to something else.
ASR33s have a 20mA (or 60mA, link selectable, I think) current loop interface. Not
RS232 (OK, I mentioned the Data Dynamics machine that used ASR33 mechanisms, 
but strictly that's not an ASR33). The most common machine (I think) with a 20mA
current loop interface is a Unibus PDP11. Hence all the comments, if you had 
one of those, you could easily link the ASR33 to it.

That said, a quick google search for 'RS232 current loop' (no quotes) throws up
a number of commerical units and built-it-yourself schematics to convert the current
loop interface to RS232. 

> All of that info seems peripheral, at best. And no, I don't have +any+ PDP
Pun intended?


More information about the cctech mailing list