The iPAQ 910c device has a mini-USB port that charges it and also used for the wired headset they send with the unit.  There is no standard 3.5mm audio jack on board.  

I searched the interwebs for any kind of adapter that would allow me to use my regular headphones to listen to music.  I’m trying to not to carry two devices with me, so if I can get rid the headphone requirement, that’s a step in the right direction in leaving my iPod/iPhone at home.

The only site I came across that has an adapter that says it works with the device is http://www.repairhppda.com/.  I haven’t ordered it yet, but plan to shortly if I can’t find anything else.

I also tried dissecting the wired headset that I got with it and didn’t have much luck in putting a female 3.5mm audio jack on one end of it.  Not sure why not, but the phone doesn’t even recognize it when it’s plugged in.

Here are some pictures of the wired headset, dissected…

 

For my car mount, I had previously purchased a dashboard mount setup from http://www.proclipusa.com that you choose custom for your car and device.  I simply unscrewed my iPhone holder and ordered the iPAQ 900 series holder from them.  Should be here in a few days.  Very happy with ProClip USA.

That’s all for now…