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Home >> Mercedes Benz >> 2016 >> E400 Base, 2D Convertible >> Repair and Diagnosis >> Electrical >> Motors, Switches, Relays >> Electrical System - Body - 212 Chassis - 1 Of 8 >> Basic Knowledge >> Two-way radio handsfree system function - GF82.25-P-2013FL

Two-way radio handsfree system function - GF82.25-P-2013FL

MODEL 212 with CODE 938 (Preinstallation for hands-free two-way radio) with CODE 965 (Electrical preinstallation, rental vehicles) 

Function requirements, general 

IMPORTANT The status of circuit 15 is sent by the electronic ignition lock control unit (N73) via interior CAN (CAN B) to the special-purpose vehicle multifunction control unit (N26/9).

Two-way radio hands-free system function, general 

The two-way radio hands-free system allows the driver to communicate, e.g. with the taxi dispatch, via the two-way radio (A49) (accessory) or the radio data transceiver (A495) (accessory). Active audio sources are automatically muted during the two-way radio call.

IMPORTANT The two-way radio is installed in the glove compartment (with code (334) Two-way radio bracket in glove compartment) and the radio data transceiver in the spare wheel well in the trunk (with code (335) Two-way radio bracket in trunk). In addition, there is the option of attaching a control panel to the accessories console (with code (333) Taxi accessories console).

Function sequence for two-way radio hands-free system 

By pressing the two-way radio cut-in switch (S93/2), the two-way radio or radio data transceiver is switched to transmission mode and the taxi driver can establish a radio connection. While speaking, the two-way radio cut-in switch must remain pressed. The speech is recorded by the taxi two-way radio microphone (B25/10). As soon as the two-way radio cut-in switch is released, it is possible to receive the voice output from the other party. This voice output is sent over two-way radio taxi speaker (H6). The two-way radio or the radio data transceiver reads in the voice entry signals of the taxi two-way radio microphone directly. The voice output is performed by the two-way radio or radio data transceiver via the taxi two-way radio speaker. The multifunction control unit reads in the status of the two-way radio cut-in switch directly and sends the signal for two-way radio cut-in via multifunction CAN (CAN K) to the two-way radio or the radio data transceiver.

The two-way radio or radio data transceiver forwards the "Transmit" signal to the multifunction antenna (A28/11) via the following route:

The voice output is now sent to the receiver of the other party via the multifunction antenna. Incoming radio signals are received by the multifunction antenna and sent to the two-way radio or the radio data transceiver. With active two-way radio cut-in, a corresponding symbol is shown in the multifunction display (A1p13) of the instrument cluster (A1). To do so, the multifunction control unit sends the request to show the status "Two-way radio cut-in active" via interior CAN to the instrument cluster.

IMPORTANT The special-purpose vehicle multifunction control unit is used as a gateway between the interior CAN and the taxi components.

The request for muting active audio sources is sent by the multifunction control unit via interior CAN, depending on the equipment, to the following control unit:

  Electrical function schematic for two-way radio hands-free system   PE82.25-P-2062-97DAA
  Overview of system components for taxi/rental vehicle   GF82.25-P-9890FL