Quadlock
From 2000 and onwards, manufacturers, such as BMW, Citroen, Ford, Mercedes Benz, Peugeot, Volkswagen, Rover, Audi, Seat, Opel and Škoda have started using a 40 pin connector instead, called the Quadlock (or Fakra, after the manufacturer). The Quadlock connector consists of a block of 16 flat pins analogous to the two main ISO 10487 connectors. While the physical contact pins are the same, the pin allocation is not entirely the same, and the connector housing is not compatible. In addition to the 16 pins, like ISO 10487, there are minor connectors for optional equipment. They fit within the frame of the main connector, and has coding so that they cannot be interchanged. Minor connector B has 12 pins for audio output signals. Minor connector C has 12 pins for various audio sources such as CD-changers, MP3 players.
| 1) right rear + | 5) right rear - | 9) I-bus (BMW) | 13) antenna (out) | |
| 2) right front + | 6) right front - | 10) phone mute | 14) illumination | |
| 3) left front + | 7) left front - | 11) tel on | 15) 12V battery | |
| 4) left rear + | 8) left rear - | 12) ground | 16) 12V switched |
Read more about this topic: Connectors For Car Audio