Does anyone know whether the pioneer deh-p6850mp has an aux input?

AUX Input via CD-RB10 or CD-RB20 adaptor

Yeah you can get them from Ryda.com.au $50.

They work well ( I have one ). I am going to get an Ipod input CD-IB100 or something soon which you can plug the Ipod in and the RCA input via 2 Bus inputs.

I have the same model in my car and below the face of the unit, there is a 2.5mm audio aux jack to plug in an MP3 player, etc.

If you want to, say, plugin a DVD player or another external unit like that, then the CD-RB10 or CD-RB20 adaptors can be used and plugged in from the back of the headunit via the IP-Bus.

i thought that the 2.5mm jack at the bottom was for a mic for time alignment?...anyway thanks heaps uys...

Yeah you can get them from Ryda.com.au $50.

or you can get a non genuine one (that works just as well) off ebay for bout $15

i thought that the 2.5mm jack at the bottom was for a mic for time alignment?...anyway thanks heaps uys...

Nope, it's an auxillary input. You can get a 2.5mm -> 3.5mm adapter for a few dollars from Dick Smith and the like. I use the front aux in on my DEH-6850MP for my iPod, as I haven't gotten around to buying the proper iPod adapter yet (don't use it much in car).

I think both the aux ins are turned off by default tho. Have to turn the headunit off and go to the options to enable them.