What is it? - sambthompson/SAAB-CDC GitHub Wiki

The BlueSaab is a small black box that replaces your Compact Disc Changer (CDC) unit in the luggage compartment. It can be used even if your car never had a CDC, as long as the CDC wiring pre-installation is present. It's been under development by Seth since September 2012. Karlis started working with Seth on the software in September 2015 and he has contributed many fixes and improvements.

The black box unit is made up of custom designed printed circuit board(s) (PCBs), various electronic components such as capacitors, resistors and integrated circuits (ICs), as well as a large 12-pin connector that the CDC plug on your car's wiring harness plugs into, all in a plastic box, with some screws and nuts.

Because it's a drop-in replacement for the CDC, BlueSaab can be fitted to cars without cutting the wiring harness or modifying the head unit. Note that you can't use the BlueSaab and the CDC together, since the BlueSaab pretends to be the CDC. The operation of the radio, tape and/or CD player in the head unit is unchanged.