Connectors for car audio

• ACC (red), supplies +12V power to car audio and other accessories, only when the car's ignition is switched on.
• Constant (yellow), also called BAT or Battery, provides permanent +12V power from battery. This allows the radio to retain settings (for example, stored radio stations) when the ignition is switched off.
• Illumination (orange with white stripe) or dimmer, when it is night and cars lights are turned on, head unit screen illumination is dimmed.
• Ground, abbrev. as GND (black), 0V, usually connected to the vehicle's metal chassis and body.

Wires with black stripes are for negative power:

• Right front speaker: gray.
• Left front speaker: white.
• Right rear: purple.
• Left rear: green.

They have low electric current, which is activated when the radio is turned on.

• Antenna: blue.
• Amplifier remote turn on: blue with white stripe.

• Phone: the cable to mute when receiving a call is brown.
• Back view, orange with white strip, works when reverse gear light is on, and it is used to turn on the back camera screen (i.e. when parking).
• Steering Wheel Controls, SWC or Key, brown with black stripe, usually employs CAN bus.

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 the ignition key), optional control for a motorised 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 and some JCB tractors.
• 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.

Connector C is optional. Sometimes 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 typically green and C3 is generally blue in colour. The contact spacing is narrower than the other connectors, so the C connector is sometimes referred to as mini-ISO.

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 ten pins.