Sony WX-C570R radio/cassette/cd head unit wiring connections?

I want to fit a Sony WX-C570R double din radio/cassette/CD head unit to my Toyota MR2 MK2.
The unit has a 16 pin connector plug on its rear FROM which there are 10 wires connected to a 10 pin plug and 4wires connected to a 6 pin plug (2 not used) and one wire not connected to either of these plugs which is marked ATT.
Can anyone assist me as to which colour wire goes where?
I assume that at least eight of the wires will be connected to the front/rear speakers and that there will be a Permanent 12v feed from battery, a 12v from the IGN Switch and an Earth (Ground)
Presumably the remaining wires are for an electric aerial and I have no idea what ATT would be.
Any help would be appreciated and any suggestions as to where I might get an owners instruction manual for this unit.