Thread: Help With pinout for F-Bus Fujitsu Ten

I want to build an aux input for my zen micro mp3 player direct to the Car head unit using the CD Changer port. I don't want to control anything, just be able to push the CD button on the HU, and play MPS from the player.
Below is the pinout for the unit. It's the OEM Radio / Cassette Head Unit for a 1995-1997 Isuzu Trooper, Fujitsu Ten( Eclipse) 7620 Radio / Casstte with a propriatary Fujitsu Ten 'F-Bus'. The precurser to the 'E-Lan'.

I don't know whether to use the square connector or the round connector and don't know whether I will need to bring a pin high to make the HU think there is a CD Changer connected or not.

I'm looking for ideas before I start working on blowing the player by connecting the wrong pins.

Any help would be appriciated. Thanks.