Re: Serial connection over Cat5 getting corrupted

[Kim Wall <kim@xxxxxxxxxxxxxxxxxx>]

Paul Gale wrote:

> Any ideas what I can do to improve the comms?

The obvious answers are "drop the baudrate" and "make sure
you haven't
got any dodgy connections".

Perhaps more usefully, wire it such that TXD and RXD both share a pair
with GND (ie. a ground in each pair).

I've got trouble-free RS232 at 19k2bps over about 20m of cat5 by doing
this (driving an old WYSE terminal in my kitchen).  It gets more than a
bit flaky at 38k4.  For comparison it was about 99% reliable at 9k6 over
the same length of Tatty Phone Extension Wire(TM), so the twisted pair
does improve things, even if it's not a truly balanced signal.

I think a big factor in this sort of thing is the quality of the RS232
line drivers in the hardware at each end, so if you've got a choice of
serial ports at the node0 end (maybe motherboard vs USB dongle vs
multiport serial card) then experiment with the alternatives.


kim.