🚀 go-pugleaf

feiges@cae.wisc.edu (Howard Feiges):
> Now, we have two phone lines...  It seems to me that when people are on
> both lines - the person on one line can faintly hear the person on the
> other line talk - and visa versa...    

It's called "crosstalk". It can happen because a) your wiring is bad, and
there's a slight resistive path between your phone lines. To test this,
disconnect the phone company from your system and use an ohmmeter between
your phone lines, between every pair of wires. The red and green, line 1,
should have infinite resistance with the phones on-hook (or, say, 10 meg if
you've wired in certain types of in-use indicators). The same for black and
yellow, line 2. Black-red, black-green, yellow-red, and yellow-green should
be infinite. (Use appropriate color names for whatever color you've actually
uused!) If you've installed or are installing a bunch of in-use indicators
that use the same circuitry for both phones, you might have to re-think it.
They could be tying your phone lines together.

The other possibility is b) electromagnetic coupling. This is like a
transformer or capacitors: moving real currents in real wires creates real
fields that can be picked up on real wires near them. The longer the wires
run next to each other, the better the coupling between them. Think of your
phone wires as a transformer without a core, unrolled all over your house.

The best way to stop this is to a) run your wires separately, or b) use
twisted pair. By twisting the red-green and yellow-black pairs at different
rates, you reduce the coupling a lot. Twisted pair wire has this done for
you. The flat silver wire, with all four wires in a plane, should only be
used for short runs (from the phone to the socket, say).

Your modem doesn't care because it's faint, and your signals are much
stronger than the noise from the other line. Your ears, however, are very
good at picking up background speech at much lower volume levels.

Let us know what you find out.....


-- 
			Nico Garcia
			CIRL/MEEI
			eddie.mit.edu!eplunix!raoul