2001 Barina/Corsa C electrical/audio

Hello, as the title suggests this is regarding the 2001 model Barina (which is a Corsa C version I believe)..

There is a socket at the base of the central dash column (the thing with the cd/stereo mounted in it) in an alcove above the ashtray/tray. Does anyone know what it is for? It is pretty chunky, I was thinking maybe it's part of the audio system (blaupunkt 2020) but I'm not sure..

I'm wanting to connect an ipod directly into the stock audio system (I don't like the RF devices). Blaupunkt have an ipod interface that works with their cd changer outlet (DMS), but this socket doesn't look like the ones I'v seen on the changers..

Anyway I'v not been able to find any good information on a) what this socket is for and b) the wiring of the audio system for this car.. Can anyone help me out?

Cheers!