[comp.dcom.telecom] Strange Phone/Laptop Interference Problem

Bill Rubin <rubin@watson.ibm.com> (05/29/91)

I was at my in-law's this past week, and ran into a strange problem.
Maybe someone out there can help diagnose it for me.  First, my setup.
I have a Toshiba laptop, with the Toshiba brand internal modem.  The
machine works on batteries, so the only time I generally use it when
it's plugged in is when I've run down my battery and haven't have a
chance to recharge it.  I was trying to use the laptop in a room where
the phone and answering machine were connected using a line splitter
at the wall jack, and the splitter didn't fit the jack very well, so
it was sticking out and easy to pull out of the wall accidentally.
There wasn't even any need for the splitter, since the answering
machine had a phone out jack, and I was using that for my laptop
connection.

Anyway, I was using the laptop with no problem under battery power,
but as soon as I plugged the computer into the AC, I started getting
wierd stuff out of the modem - and it sounded like it was picking up a
radio station!  I tried a couple of different outlets, turning on and
off the answering machine, but the only thing that could make the
modem work was to unplug the machine from the AC, either at the
laptop, or the outlet.  Oh yes, when this was occurring, I was unable
to dial using the regular phone as well, it got the same interference.

So, my question is, what was going on?  Is it possible that the very
poor fit of the phone splitter was allowing phone signals to be jammed
by whatever was coming out of the laptop?  But if so, why should it
only occur when I was using the AC?  Any suggestions are appreciated.


Bill  rubin@watson.ibm.com