GF82.25-P-2014FL Two-Way Radio Integration Function

GF82.25-P-2014FL Two-way Radio Integration Function
- with CODE (965) Electrical preinstallation for rental vehicles
- with CODE (941) Preinstallation for radio data transmission


Function requirements, general
^ Circuit 15 ON

The electronic ignition lock control unit (N73) sends the status of circuit 15 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 incl. CD changer)
- Radio with autopilot system (A2/56) (with code (525) Radio MB Audio 50 APS or code (511) Audio 50 APS incl. DVD changer)
- COMAND control unit (A40/3) (with code (527) COMAND APS with single DVD drive (with navigation) or code (512) COMAND APS incl. DVD changer)

Two-way radio integration, general
The two-way radio integration is a preinstallation for the operation of the voice radio transmission and radio data transmission that allows the driver to establish communication, e.g. with the taxi main office, via the radio data transmission two-way radio (A49/5) (accessories).

The two-way radio integration is comprised of the following partial functions:
^ Function sequence for switching on the radio data transmission two-way radio
^ Function sequence for switching off the radio data transmission two-way radio
^ Function sequence for fault detection

Additional function requirements for switching on the radio data transmission two-way radio
^ Taxi mode activated in the menu "Settings", Taxi", "Operation: Business" in the instrument cluster (A1)

Function sequence for switching on the radio data transmission two-way radio
The radio data transmission two-way radio 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 right multifunction steering wheel button group (S111) or using the buttons on the audio equipment, a radio connection, e.g. with the taxi main office, can be established via the radio data transmission two-way radio. The communication via two-way radio is cyclically sent to an output (two-way radio source) of the multifunction control unit. If the cyclical two-way radio source is interrupted, this can be activated again following t = 5 s.
The multifunction control unit sends status information via interior CAN to the instrument cluster and the audio equipment. The display takes place in the multifunction display (A1p13) of the instrument cluster or in the Audio/COMAND display (A40/8), which receives the information via telematics CAN (CAN A) from the audio equipment.
Pressing the multifunction steering wheel button groups or the buttons on the audio equipment signals the multifunction control unit that a two-way radio connection should be activated.

The signals of the multifunction steering wheel button groups are read in by the steering wheel electronics (N135) and transmitted via the steering LIN (LIN E1) to the steering column tube module control unit (N80).
The steering column tube module control unit routes the signals via chassis CAN (CAN E), 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 transmission two-way radio via multifunction CAN (CAN K).


Alternatively, the radio data transmission two-way radio can also be activated upon unlocking the central locking (CL [ZV]) if taxi mode was not switched off beforehand.
The FM, AM, CL [ZV] and KEYLESS-GO antenna amplifier (A2/18) receives the radio signals of the transmitter key (A8/1) and forwards them via rear SAM control unit with fuse and relay module (N10/2) to the electronic ignition lock control unit.

The electronic ignition lock control unit sends the status "CL [ZV] unlocked" via interior CAN to the multifunction control unit which then activates the radio data transmission two-way radio via multifunction CAN.

Function sequence for switching off the radio data transmission two-way radio
The radio data transmission two-way radio 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 transmission two-way radio, the message "Charge two-way radio with +" appears in the multifunction display.
In addition, three beeps sound that are output via the warning buzzer (A1h1).

If the radio data transmission two-way radio 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 transmission two-way radio can only be activated by pressing the multifunction steering wheel button groups, the buttons on the audio equipment or by triggering an emergency alarm with radio help call.

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

The FM, AM, CL [ZV] and KEYLESS-GO antenna amplifier receives the radio signals of the transmitter key and forwards them via rear SAM control unit to the electronic ignition lock control unit. The electronic ignition lock control unit then sends the status "CL [ZV] locked" via interior CAN to the multifunction control unit.

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