[net.dcom] Having trouble with a cable under a

jbn@wdl1.UUCP (01/18/85)

     There are all kinds of neat ways to get polyphase hum, but the real
question is whether the hum is common-mode or not.  If you short one end
of the line together and put an isolated scope across the other end, is
the hum unreasonable?  If not, all you need is some kind of short-haul
modem with good common-mode rejection.  You might even be able to get away
with sending RS-232 signals down the line if the devices at both ends
really implement the spec right, which calls for a -12 to +12 swing with
anything in the -3..+3 range ignored.  Just some RS-232 booster might be
good enough.  Get a Glasgal Communications catalog and look for something
suitable.