There seems to be a lot of debate behind the cell phone usage ban on airplanes. A lot of cell phones now have airplane modes so we can enjoy out electronic devices in peace while aboard commercial aircraft. We keep hearing how cell phone communication could interfere with the aircraft instruments and devices. The ban was put into place in 1991 and was almost lifted in 2007, but was upheld by the FCC. I am curious what devices technically do they interfere with? What exact instruments do cell phones radio frequencies potentially interfere with? What on an aircraft uses similar radio frequencies? Or is it all just a general concern since there is a lot of electronic communication that needs to take place for an aircraft to operate safely?
EDIT: This could apply to smart phones, laptop data cards, and other devices (Kindle, etc.) that connects to the cell networks while on aircraft.