On Fri, Jun 04, 1999 at 09:16:45AM -0500, Eric Oliver wrote:
> I probably should keep my mouth shut since I'm not an expert <g>, but I'm
> not aware of a standard per se for RJ-11.  Normal phone connections start
> at the center two pins and work their way out for each line.

I have been working with these kinds of things for many
years and have never noted a "standard" for RS-232. It
makes very little difference in reality, and it seems
that everyone just makes something up, so you have little
hope of minimizing compatiblity issues. The only concern
would be if one had to mate with an existing device, in
which case you would probably want to pick a pinning
that would allow you to use a straight-through cable
to the other unit (swap your TX & RX pins, if necessary,
on the device side of the RJ-11 jack, not inside the patch
cable); then you can use any old standard off-the-shelf
RJ11 patch cables.

If you have an RS-422 interface, then the pinning and
the patch cable can become more of a concern, because
for optimal performance you'd like the TX+ and TX- on one
twisted pair and the RX- and the RX+ on another.

--Bob

--
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Bob Drzyzgula                             It's not a problem
bob@drzyzgula.org                until something bad happens
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