Two-way radio integration function - GF82.25-P-2014FL

MODEL 212 with CODE 941 (Preinstallation for radio data transmission) with CODE 965 (Electrical preinstallation, rental vehicles) 

Function requirements, general 

• Terminal 15 ON

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).

The designation "audio equipment" is used for the following control units, which are installed depending on the equipment:

• Radio (A2) (with code (523) Radio MB Audio 20 or code (510) Audio 20 with CD changer)
• Radio with autopilot system (A2/56) (with code (525) MB Audio 50 APS radio or code (511) Audio 50 APS with DVD changer)
• COMAND controller unit (A40/3) (with code (527) COMAND APS with single DVD drive (with navigation) or code (512) COMAND APS with DVD changer)

Two-way radio integration, general 

The two-way radio integration function is a preinstallation for operation of the voice and radio data transmission that enables the driver to communicate, e.g. with the taxi dispatch, using the radio data transceiver (A49/5) (accessory).

The two-way radio integration function comprises the following subfunctions:

• Function sequence for switching on the radio data transceiver 
• Function sequence for switching off the radio data transceiver 
• Function sequence for fault detection 

Additional function requirement for switching on the radio data transceiver 

• Taxi mode activated in the menu "Settings", Taxi", "Operation: Business" in the instrument cluster (A1)

Function sequence for switching on the radio data transceiver 

The radio data transceiver is a preinstallation for the two-way radio that is located in the spare wheel well in the trunk. Using the left multifunction steering wheel button group (S110) and the right multifunction steering wheel button group (S111) or the buttons on the audio equipment, a wireless connection, e.g. with the taxi dispatch, can be established over the radio data transceiver.

The multifunction control unit sends status information that is to be displayed on the multifunction display (A1p13) of the instrument cluster via interior CAN. The multifunction control unit also sends the status information via interior CAN, audio equipment and telematics CAN (CAN A) that is to be shown on the Audio/COMAND display (A40/8). Pressing the multifunction steering wheel button groups or the buttons on the audio equipment signals the multifunction control unit that a two-way radio cut-in should be activated.

The signals of the multifunction steering wheel button group are read in by the steering wheel electronics (N135) and sent up to 28.2.13 via steering LIN (LIN E1), steering column tube module control unit (N80) and chassis CAN (CAN E) or as of 1.3.13 via chassis CAN 1 (CAN E1), front SAM control unit with fuse and relay module (N10/1) and interior CAN to the multifunction control unit. The audio equipment sends the control signals of the buttons on the audio equipment via interior CAN to the multifunction control unit. The multifunction control unit then activates the radio data transceiver via multifunction CAN (CAN K).

Alternatively, the radio data transceiver can also be activated upon unlocking the central locking (CL [ZV]) if taxi mode was not switched off beforehand.

Vehicles without code (889) Keyless-Go:

When the Unlock button on the transmitter key (A8/1) is pressed, it forwards the request via the rear window antenna (A2/32), the FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier (A2/18), the rear SAM control unit with fuse and relay module (N10/2) and interior CAN to the electronic ignition lock control unit.

Vehicles with code (889) Keyless Go:

When the Unlock button on the transmitter key is pressed, it forwards the request via the rear window antenna, the FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier, the KEYLESS-GO control unit and interior CAN to the electronic ignition lock control unit.

The access authorization for the transmitter key is checked in both cases by the electronic ignition switch control unit. If the access authorization is valid, the electronic ignition lock control unit sends the "CL [ZV] unlocked" status via interior CAN to the multifunction control unit, which then activates the radio data transceiver via multifunction CAN.

Function sequence for switching off the radio data transceiver 

The radio data transceiver can be switched off manually or automatically. This is performed manually via the multifunction steering wheel button groups or the buttons on the audio equipment. To do so, the "Two-way radio" menu must be selected in the instrument cluster. After switching off the radio data transceiver, the message "Charge two-way radio with +" appears in the multifunction display. Three beeps are also sounded which are emitted by the instrument cluster via the warning buzzer (A1h1).

If the radio data transceiver was switched off via the right multifunction steering wheel button group or the buttons on the audio equipment, it cannot be activated by unlocking the CL [ZV] or switching on circuit 15 C. The radio data transceiver can then only be activated by operating the multifunction steering wheel button groups, the buttons on the audio equipment or by issuing an emergency alarm using the radio emergency call (with code (934) Taxi emergency alarm system).

If the CL [ZV] is locked with the transmitter key, the multifunction control unit automatically switches off the radio data transceiver after the expiration of a programmable time (standard t = 30 m).

Vehicles without code (889) Keyless-Go:

If the Lock button on the transmitter key is operated, it sends the request via the rear window antenna, the FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier, the rear SAM control unit and interior CAN to the electronic ignition lock control unit.

Vehicles with code (889) Keyless Go:

If the Lock button on the transmitter key is operated, it sends the request via the rear window antenna, the FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier, the KEYLESS-GO control unit and interior CAN to the electronic ignition lock control unit.

The access authorization for the transmitter key is checked in both cases by the electronic ignition switch control unit. If the access authorization is valid, the electronic ignition lock control unit sends the "CL [ZV] locked" status via interior CAN to the multifunction control unit.

Function sequence for fault detection 

If the radio data transceiver does not answer 50 consecutive status queries within the permissible time, e.g. due to an internal overload, the radio data transceiver is disconnected from the power supply for approx. t = 5 s. The radio data transceiver is returned to a functioning state by means of this "power-off reset". The multifunction control unit ends any dialogs with the instrument cluster that are still open. A "power-off reset" is signaled by the warning buzzer in the instrument cluster by 5 beeps. After approx. t = 5 s, the radio data transceiver is supplied with voltage again and receives status queries.

	Electrical function schematic for two-way radio integration		PE82.25-P-2063-97DAA
	Overview of system components for taxi/rental vehicle		GF82.25-P-9890FL