hachti at hachti.de
Wed May 24 05:45:11 CDT 2017
On 23.05.2017 03:41, Ethan Dicks via cctalk wrote:
> No eye-rolling here. Nice find!
Here the same. Perhaps not the most wanted device - but... better have
>>> I got home last night, and the unit fires up and works (well, in local mode. Docs claim
>>> it is rs232 out the back, but could not coax anything from my PC to it yet),
> Do you have a "traffic light"? I find them invaluable for diagnosing
> handshaking and TxD/RxD swaps.
The first thing I thought of. Everybody needs one. And 25/9-Adapters in
both directions, null modem cables and gender changers - then you get
everything running. Ok, add some sub d connectors to make weirdly wired
adapters if nothing helps.
>> Does your PC have real RS232? A lot of "RS232" ports are serial ports, but not with correct
>> RS232 levels. If you have "TTL RS232" [sic] it won't work with an actual RS232 port.
I don't think that it's reasonable to check this problem first. Of
course, can happen. But more likely you have a null modem problem.
Keep in mind that "TXD" is the output of a DTE (Data Terminal
Equipment). TXD is therefore the input (!) of a DCE (Data Communication
Equipment aka modem).
PC RS-232 ports send on TXD because they consider themselves to be a
terminal. And a teletype IS actually a terminal. So you would need to at
least cross wires 2 and 3 (RXD/TXD) using a Null modem. If you want
hardware handshake, the same applies to DTR and CTS.
Good luck :-)
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