The phones do communicate regularly with the network. The network must be
constantly updated with whose phones are switched on and which cell tower
is
providing service. (It would be impractical to ring you for an incoming
call if the network had to query every tower in the world, "Hey, I have a
call for DougSlug. Who has him???")

This is a surprisingly common form of Electromagnetic Interference (EMI).
The RF is being coupled into the wiring and changing the conduction of the
small transistor amplifier inside one of the speakers, the one with the
light and switches.

At work, I usually know when my co-workers cell phone will ring, because
MY
speakers emit a bup-bup-bup-buzz right before the ring. See, he usually
keeps his phone next to the cubicle panel on his side, but by chance just
inches away from my speakers. I have heard the same thing on TV, when a
performer is wearing both a wireless mike and a cell phone.


I got my first cell phone about 8 months ago and it didn't take long for me
to run into this. At work I have headphones on most of the time, listening
either to AM radio or to an audio cassette (both from the same Walkman-type
unit). Those brief digital bursts occur about every 10 minutes and if the
headphone cord is close to my cell phone, the sounds can be very loud in the
headphones. I've even heard the bursts coming from the speakers connected
to my home stereo, with the audio source not running (connected to CD
player, but volume is still turned up), and the cell phone is lying on the
table in the next room.

As you said, with a bit of practice I can tell if my cell phone is actually
about to ring or is just checking in with the network. A couple of days ago
the digital pattern was of a type I'd never heard before and when I looked
down to look at my phone, I found that someone had sent me a text message (a
feature I normally don't use).

I mentioned this recently to a friend of mine and he told me about a
somewhat similar experience that happened to him when he was a kid, about 25
years ago. He lived in a house with somewhat ancient telephone wiring and,
for some reason he never did figure out, the telephone would emit a very
brief "ghost ring" right before it would ring for real. That is, it was an
electromechanical phone (this was early 1970s) and before the first
"genuine" ring, the phone would first put out one very brief "ping."
Apparently there was something in the telephone network that would send out
a very brief "pip" that would ding the bell just once (the actual ring is a
constant string of pulses). As a boy in his early teens, my friend noticed
this but said nothing about it to anyone else. Whenever he was in the house
and heard that brief "ping," he knew that the telephone would ring a couple
of seconds later. He had an aunt who was loud, obnoxious, stupid, five feet
in all directions, and totally clueless about technology; whenever she'd
come by the house for a visit, my friend would terrorize her by hollering
"PHONE'S GONNA RING!!!!" about two seconds before it actually did. She
never noticed the "ghost pings." She never did catch on and was totally
convinced that he was possessed.
Some time later, the tables got turned on him, briefly. Whenever
he was in the house alone, with total quiet, sometimes he could hear voices
and couldn't figure out where they were coming from. It wasn't constant,
either. Very faint whispers. Very strange. They seemed to be coming from
the kitchen and he couldn't quite bring himself to believe that he was
hearing ghosts. He finally got the clue he needed late one night when he
raided the refrigerator and distinctly heard the '70s song "The Sound of
Philadelphia" coming from nowhere. He couldn't picture a bunch of ghosts
sitting around a kitchen playing disco music, so he poked around and finally
discovered the source of all this: a flashlight! It was an old-style
flashlight, with two batteries, an incandescent bulb, a metal case, and a
big magnet so it would stick to the fridge. Apparently the spring inside
the flashlight was forming a junction diode and was rectifying an AM radio
station signal. The "voices" were apparently from a talk show during
certain hours.