Portable devices
 

This question is purely academic(I'm a humble ppl with an a level in physics) what is it with mobile electronic devices such as i-pods or perhaps portable dvd players that can affect the Aircrafts electronics?
I can see the problem with mobile phones when being used to transmit calls etc, but don't understand the portable appliances issue

Possible RF interference when both the device and the airplane have improperly shielded wiring. Remember that even "non-transmitting" devices give off RF energy that may escape the boxes if improperly shielded.

I have seen reports in the past of problems in specific small commuter-type airplanes. Whether it was because of inherent design defects or maintenance problems, I don't know...