the CDC input is at the back of the headunit. there are 3 'mini-ISO' plugs, and the BLUE one is for the CDC (green = steering/phone, yellow = remote output wire for Bose amp when applicable).
photo of what i'm referring to (photo taken for other purposes):
http://pic20.picturetrail.com/VOL97/.../291648346.jpg
it MAY depend upon what model headunit the car has. this is the schematic stuck atop my factory headunit:
http://pic20.picturetrail.com/VOL97/.../291012684.jpg
the factory headunit, whilst designed by blaupunkt, is tweaked for alfa romeo. as such, a blaupunkt iPod cable does NOT work properly. by 'OE iPod cable', i am referring to the iPod option that alfa romeo dealers have offered for the GT/147, which is cable+'drawer' that replaces the cup/cardholder.
italiaspeed.com - Alfa Romeo
however, people have said it has been hard to source this accessory in recent months - ?discontinued?
though Connects2 have a version that others are using:
http://www.alfaowner.com/Forum/ice-a...-in-147-a.html (Connects2/iconnect for ipod in 147)
the iPod cable utilises the 'docking port' on the bottom of your iPod (excl Shuffle). this is the best 'sound quality' connection because it bypasses the headphone 'amplifier' circuitry, which adds hiss/noise.

GT . 3.2L V6 . Q2 . Kyalami Black - Red . Eibach . KONI . ATP 19" . TOYO Proxes4 . Mille Miglia exhaust
155 . 2.0L 8V TS . Grigio Grey - Grey . Eibach . Bilstein . Enkei 17" . Bridgestone RE001 . REMUS