Connectors for car audio

Several types of connectors for car audio systems are used.

Splicing wires

Splicing wires used in car audio are mainly for power, ground, amplifier and antenna, speakers, phone and others.

Power and ground

  • ACC (red), supplies +12V power to car audio and other accessories, only when the car is ignited.
  • Constant (yellow), also called BAT or Battery, provides permanent +12V power from battery.
  • 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.

Speakers

Wires with black stripe are for negative power:

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

Amplifier and Antenna

They have low amperage and it is activated when radio is turned on.

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

Phone And Others

  • 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 back camera screen (i.e. when parking).
  • Steering Wheel Controls, SWC or Key, brown with black stripe, usually employs CAN bus.

ISO 10487 Harness Adapter

ISO connectors for head unit in car
ISO 10487 connector in car, fits into head unit

ISO 10487 was created in 1995 and 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.

ISO 10487 connector pinout
ISO 10487 connector pinout (plug side of male, wiring side of female)

Parts

Part 1 of the standard is dedicated to "Dimensions and general requirements" and Part 2 to "Performance requirements".

Power (A)

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 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

Loudspeaker (B)

The second connector B is for connecting four loudspeakers, front, rear, left and right, and is usually brown in colour.

Miscellaneous (C)

The 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 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.

C1 (external amplifier)
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
C2 (remote control)
7) receive data 10) +12V switched (out)
9) chassis ground 12) remote control ground
8) transmit data 11) remote control in
C3 (CD changer)
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.

Navigation (D)

The connector D is for satellite navigation systems. It has 10 pins.

Quadlock

From 2000 and onwards, manufacturers, such as BMW, Citroen, Ford, Mercedes Benz, Peugeot, Volkswagen, Rover, Audi, Seat, Opel or Škoda have sometimes started using a 40-pin connector instead, called the Quadlock. 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.

Quadlock A
1) right rear + 5) right rear - 9) I-bus (BMW) / Canbus+ 13) antenna (out)
2) right front + 6) right front - 10) phone mute / (Speed Signal) 14) illumination
3) left front + 7) left front - 11) tel on / Canbus- 15) 12V battery
4) left rear + 8) left rear - 12) ground 16) 12V switched

See also

External links

Automotive head unit

An automotive head unit, sometimes referred to as a deck, is a component of an automotive infotainment, which provides a unified hardware interface (mainly, the screen and buttons) for the entire system.

Antiquated names for head unit are receiver, in-dash stereo or dash stereo.

Fuse (automotive)

Automotive fuses are a class of fuses used to protect the wiring and electrical equipment for vehicles. They are generally rated for circuits no higher than 32 volts direct current, but some types are rated for 42-volt electrical systems. They are occasionally used in non-automotive electrical products.

ISO 7736

International standard ISO 7736 defines a standard size for car audio head units and enclosures. The standard was originally established by the German standards body Deutsches Institut für Normung as DIN 75490, and is therefore commonly referred to as the "DIN car radio size". It was adopted as an international standard in 1984.

Head units generally come in either single DIN (180 x 50 mm panel) or double DIN (180 x 100.3 mm panel) size. The depth is not standardized; as a result, some cars such as the Opel Manta / Ascona have the correct sized front aperture but will accommodate few DIN sized radios other than the original due to the shallow depth; this despite the vehicle being manufactured as late as 1988. The US standard for a DIN radio is 6.83" x 2" (although the actual 180 mm width converts to something like 7-3/32" so most people use 7-1/8" to allow for clearance) and the Double DIN sized radio is a 7" x 4". Some radios in Japanese Kei cars do not conform to the DIN standard however.

Metra Electronics

Metra Electronics (Holly Hill, Florida) is an American automotive electronics company established in 1949, specializing in audio electronics systems and 12 volt accessories.

Vehicle audio

Vehicle audio is equipment installed in a car or other vehicle to provide in-car entertainment and information for the vehicle occupants. Until the 1950s it consisted of a simple AM radio. Additions since then have included FM radio (1952), 8-Track tape players, Cassette Players, CD players (1984), DVD players, Blu-ray players, navigation systems, Bluetooth telephone integration, and smartphone controllers like CarPlay and Android Auto. Once controlled from the dashboard with a few buttons, they can now be controlled by steering wheel controls and voice commands.

Initially implemented for listening to music and radio, vehicle audio is now part of car telematics, telecommunication, in-vehicle security, handsfree calling, navigation, and remote diagnostics systems. The same loudspeakers may also be used to minimize road and engine noise with active noise control, or they may be used to augment engine sounds, for instance making a smaller engine sound bigger.

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