14 Jun
2012
14 Jun
'12
1:16 p.m.
that I
didn't know what pin was what on the system, the problem was
what pin was what on the connectors I wanted to buy.
Sure. The point of my (and
others) post was that if you get _any_
adapter you can then use the RS232 tester to figure otu which is TxD
and which is RxD, and if necessary make up an adapter using
easy-to-get DB25 conenctors to lin kit to your terminal. That might
not be as neat as having the right adapter, but it will get the thing
working.
(2) I've even seen one device which powers down its transmitter unless
it sees at least one input pin being driven. This is extremely
I assuem it also powers down the drivers for any flow control outputs.
That is plain evil. What device does this?
annoying, because when you go in with a meter (or
lights) to figure out
which pins are being driven you find that none of them are. It also
means that you can't test it by just shorting TxD to RxD even if the
software is configured to ignore modem control signals. Mercifully,
such devices seem to be rare; I've seen only one, out of all the serial
ports I've dealt with, as far as I know.
A third thing you cna't test with the light adapter on its own is an
RS232 drvice that's powered from the RS232 signals, like some (most?,
certainly not all) serial mice.
I think it's fair to say that no solution works in _all_ cases. That
doesn't mean the LED adapter is not handy to have around. It works in
enough cases that it's a useful thing to have in the toolkit.
-tony