I started a thread earlier but that was when i had only identified one issue with iPhone's audio. iPhone headjack: Apparently a lot of standard headphones and 3.5mm line out cables won't work with the iPhone headset jack. Not because of the headjack port itself but rather because of the narrow recession on the case of the iPhone. The recession is so narrow that it won't let the male end of the cable sit all the way down, thus not allowing you to use some(most?) standard headphones. iPhone pin connector: I haven't done a lot of testing but so far, I've tried 2 devices that normally allow iPod audio out through the PIN connector, and they do not work with iPhone. The audio continues to play through the mini speakers; doesn't recognize the accessories; only for charging. If anyone has information on a work around, other info that might help please post it.