Component description for sound system amplifier control unit

P82.62-3959-04

P82.62-4284-04

Location

Model 205

The sound system amplifier control unit is located in the trunk behind the cover for the right sidewall on a bracket.

Model 253

The sound system amplifier control unit is located under the trunk floor in front of the right rear lamp unit (E4).

Tasks

The sound system amplifier control unit has the following tasks:

 Receive signals

 Signal optimization and amplification

 Actuation of components

Receive signals

The sound system amplifier control unit receives the input factors via the following connections:

 Direct lines

 Media Oriented System Transport (MOST)

 CAN (model 205.0 as of model year 2019, model 253 as of model year 2020 with code B63 (Sporty engine sound))

Direct lines

The sound system amplifier control unit reads the following signals via direct lines:

 Wake-up signal from the head unit (A26/17)

 Request to mute audio sources (mute function) from:

 Emergency call system control unit (N123/4) (with CODE 348 (Emergency call/assist system))

 Telematics services communications module (N112/1) (with code 350 (eCall Europe emergency call system) or code 06U (Mercedes connect me basic services))

 HERMES control unit (N112/9) (with code 360 (HERMES UMTS) or code 362 (HERMES LTE))

 Audio signals from the engine sound control unit (N40/1) (model 205.0 up to model year 2019, model 253 (except 253.99) up to model year 2020 with code B63 (Sporty engine sound))

MOST

The sound system amplifier control unit is a MOST subscriber and receives the following signals:

 Control and audio signals from the head unit

 Control and audio signals from the tuner unit (A90/4) (model 205.0 up to model year 2019, model 253 (except 253.99) up to model year 2020 with code 536 (SIRIUS satellite radio) or code 537 (Digital radio (DAB)) or code 865 (TV tuner))

 Control and audio signals from the TV tuner control unit (N143) (model 205.0 as of model year 2019, model 253.99 with code 865 (TV tuner))

 Speed signal from the head unit, for speed-dependent volume control (SDV)

CAN (model 205.0 as of model year 2019, model 253 as of model year 2020 with code B63 (Sporty engine sound))

The sound system amplifier control unit receives control signals (e.g. engine speed, engine load and vehicle speed) via the drive CAN (CAN C1) from the ME-SFI control unit (N3/10) and from the powertrain control unit (N127).

Signal optimization and amplification

 Optimization of the input signals through digital signal processing

 Decoding of copy-protected audio signals based on digital signal processing technology

 Support of stereo and multichannel entertainment channels and announcement channels (e. g. for voice output in voice control system or navigation prompts)

 Amplifying of the input signals and assignment of the output to the speakers

 Processing of synthesized sound signals from the engine sound control unit (with code B63 (Sporty engine sound))

Actuation of components

The sound system amplifier control unit emits the audio signals via the following speakers:

 Center instrument panel speaker (H4/27)

 Left footwell woofer (right-hand drive vehicles) (H4/42)

 Right footwell woofer (left-hand drive vehicles) (H4/43)

 Left rear midrange speaker for surround sound system (H4/62)

 Right rear midrange speaker for surround sound system (H4/63)

 Left front door tweeter (H4/68)

 Right front door tweeter (H4/69)

 Left rear door/side wall trim tweeter (H4/70) (except model 205.3/4)

 Right rear door/side wall trim tweeter (H4/71) (except model 205.3/4)

 Left front door midrange speaker (H4/72)

 Right front door midrange speaker (H4/73)

 Left rear door/side wall trim mid-range speaker (H4/80) (except model 205.3/4)

 Right rear door/side wall trim mid-range speaker (H4/81) (except model 205.3/4)

 Left rear side wall trim mid-range speaker (H4/102) (model 205.3/4)

 Right rear side wall trim mid-range speaker (H4/103) (model 205.3/4)

 Left rear side wall trim tweeter (H4/104) (model 205.3/4)

 Right rear side wall trim tweeter (H4/105) (model 205.3/4)

The sound system amplifier control unit is actuated via the head unit. The head unit also provides all of the menus for user guidance. The software update and diagnosis communication also occur via the head unit.

For the optimized speed-dependent volume adjustment, the sound system amplifier control unit evaluates the vehicle speed signal and noise level in the vehicle interior via the hands-free system.