Ever since I got the iPhone, I’ve noticed that it causes nearby speakers (radios, desk phones, etc) to emit a buzzing noise.
The odd thing is, my boss Brian’s Blackberry does the same thing.
I finally found the reason why:
The cause of this buzzing has to do with GSM’s “time division nature. The ever-knowledgeable Keith Nowak, spokesperson for Nokia, explains it as follows: “[[With GSM]] the RF transmitter is turned on/off at a fast rate, and that ‘pulsing’ is often picked up by nearby devices that don’t have good RF shielding. In the case of GSM the pulse rate is 217 Hz, which can be easily heard.
When I put my iPhone in the clock radio / iPhone dock that Ginny got me for the holidays, it does the same thing. Luckily the dock isn’t recognized as being 100% iPhone compatible, so the iPhone offers to shut off the radio (go into Airplane mode) whenever I dock it. This eliminates the buzzing (mostly) because the phone isn’t transmitting.