ISO 10487 defines a standard for connectors for the head unit to the car’s electrical system, consisting of a system of four different connectors typically used in head units for car audio.
Part 1 of the standard is dedicated to “Dimensions and general requirements” and Part 2 to “Performance requirements”.
The first connector A is always present, is usually black in colour, and contains pins for power-supply, off/on (typically controlled by ignition key), optional control for a motorized antenna and so on.
- On some cars the +12V Ignition and Battery positions are reversed, such as later Volkswagen Group cars, Peugeot 106,Vauxhall Astra, Citroën C3.
- Pin 1 is optional; used for speed dependent volume control and possibly navigation.
- Pin 2 is optional; used for phone mute
- Pin 3 is optional; used for reversing lamp signal on Becker radios with navigation.
- Pin 6 is optional; used for vehicle instrument illumination
The second connector B is for connecting four loudspeakers, front, rear, left and right, and is usually brown in colour.
The connector C is optional. Some times, it appears as one 20-pin connector, often red in colour, or it may be divided into three separate connectors which may be hooked together, in which case C1 is usually yellow, C2 is usually green which C3 is usually blue in colour. The contact spacing is narrower than the other connectors, so the C connector is sometimes referred to as mini-ISO.
|1) line out left rear||4) line out left front|
|3) line out common ground||6) +12V switched (out)|
|2) line out right rear||5) line out right front|
|7) receive data||10) +12V switched (out)|
|9) chassis ground||12) remote control ground|
|8) transmit data||11) remote control in|
|13) data in (bus)||16) +12v switched (out)||19) audio left|
|15) +12v permanent (out)||18) audio ground|
|14) data out||17) data ground||20) audio right|
Note: ISO 10487 only defines the physical attributes of the connectors, not the pin/signal designations, which are manufacturer-defined. The example above is oriented towards VW vehicles only.
The connector D is for satellite navigation systems. It has 10 pins.
Source: ElectroDroid and Wikipedia