In my office we often experience instances of a "galloping" sort of buzz
periodically coming from the PC speakers near co-workers who have Cingular
GSM cell phones. A preliminary Web search turns up many instances of this
problem. My understanding is that these phones periodically communicate with
the network, and during these brief bursts the carrier is modulated at
around 200 Hz resulting is a clear, repeatable buzz pattern. How is this
buzz getting into the PC speaker amplifier, and, more importantly, how can
it be prevented?

Thanks,
Doug