USB for Mic jack

So a friend recently asked me if it would be possible to replace the USB jack on a set of headphones with a Mic jack so it could be plugged into and ipod. I said I wasn't sure. I know it isn't really robot related but it was an electronics question and I figured this was a good place to ask it. Thanks

A quick internet search says …

No. One forum post I saw said that the usb headset likely makes some use of the port, either for digital-analog(audio) conversion or to power something like a subwoofer.

Thanks

Ok, thanks for your help.