I want to fit an aftermarket radio to my volvo 940 but the existing large head unit has a rectangular single rectangular plug with about 12-14 wires on it and a round silver 'din' cable plugged into the 'back left' of the unit. Does this din cable indicate that this vehicle has an amplifier fitted? or is this for a cd changer. I know I will require an adaptor plate and iso wiring adapter but I am mostly concerned about this 'din' connector. Can anyone help? Thanks.