The only time MY phone has rung when onboard (and when I've forgetten to turn the thing off
) is when I've been taxiing out or taxiing in. "Mid-flight"? Never. So, if this one did start ringing at that point of the flight my ears would prick up. Where would a calling signal be coming from?
As for hearing a phone in the hold, not bloody likely.....
Sounds like another story where there's more to it, OR has been distorted by the media, just for something completely different.