[avian]

The effect of GSM phones on analog audio equipment was actually an oversight in defining the standard. Fully compliant equipment had that effect.

Some years back when I had some small involvement in new EU regulations that case was actually given as an example of how, even after many reviews, some forms of harmful interference can only become apparent after a technology is already widely deployed.

[Johnythree]

No, the interference from GSM is caused by poor immunity in the audio equipment. You can't blame the EU standard for crappy analog audio equipment.

The RF breakthrough is caused by the Amplitude Modulation in GSM, but then there's nothing fundamentally wrong with AM.