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

tony duell ard at
Fri Nov 21 14:59:12 CST 2014

> So at least we're on the same page so far as RS-232 -> 20mA converters are
> concerned. I've been looking at that stuff today.. and here's something
> that seems too easy.
> Is there any reason that I couldn't pick up a cheap, common RS-232 to TTL
> converter module (like eBay item 310624019670 - about $5) and connect the
> TTL side to an opto-isolated transceiver pair like the HCPL-4100 / 4200?
> The DIY schematics I've seen are essentially  RS-232 to TTL converters
> (using the MAX232 IC) that directly drive the 4100/4200 pair.
> Like I said, seems too easy.. but why wouldn't it work?

I suspect that most, if not all, of those RS232-TTL converters are just 
a MAX232 + the necessary capacitors, or something very similar. 

Of course I've not tried it but I can see no reason why it wouldn't work.
On the other hand, I can see no reason not to just buy the MAX232 chip,
since you'll have to mount and solder up the optoisolators and associated
components anyway.


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