Dedicated Short-Range Communications (DSRC), function

P82.88-A001-76

Function requirements for Dedicated Short-Range Communications in general

 Circuit 15R ON (from electronic ignition lock control unit via user interface CAN)

 Transport mode not active

 Electronic Toll Collection System (ETC) card inserted

Dedicated Short-Range Communications in general

The Dedicated Short-Range Communications (DSRC) system combines the following functions:

 Payment of toll fees from the vehicle in the Electronic Toll Collection (ETC) system

 Advantages of Vehicle Information and Communication System (VICS) services

The ETC system includes not only payment at the tollbooth but also a detailed list of payments made, which is created in the head unit.

The services provided through VICS in a reception range of 5.8 GHz include, e.g.:

 Warning of obstacles in stretch ahead

 Information on traffic conditions in stretch ahead

 Warning if separate lanes are merged in the stretch ahead.

 Electronic direction signs

 Messages from the disaster early warning system (e.g. earthquake and Tsunami warnings)

For the purposes of dynamic route guidance, VICS information is received in a reception range of 2.5 GHz or infrared signals from the Vehicle Information and Communication System (VICS) control unit and in a reception range of 5.8 GHz through the Dedicated Short-Range Communications control unit. The traffic messages are stored in the traffic data recorder of the head unit, decrypted and forwarded to the navigation processor on request.

Function sequence for Dedicated Short-Range Communications

For the data exchange of ETC, and VICS data in a frequency range of 5.8 GHz the vehicle is equipped with a DSRC antenna and the Dedicated Short-Range Communications control unit. The DSRC antenna allows the Dedicated Short-Range Communications control unit to communicate with the tollbooth and to receive the VICS information in the 5.8 GHz range.

For the reception of microwave signals in a reception range of 2.5 Gigahertz or infrared signals, the Vehicle Information and Communication System (VICS) control unit is connected to the Dedicated Short-Range Communications control unit. The Vehicle Information and Communication System (VICS) control unit contains both the receiver and the antenna. The antenna receives VICS information from the VICS beacons installed at the side of the road (transmission masts).

 A special ETC card is required for the ETC system and it has to be inserted in the Dedicated Short-Range Communications control unit. All information concerning the user and the fees that have already been paid are stored on this card.

At the vehicle side, the Dedicated Short-Range Communications control unit is connected to the head unit via a universal serial bus (USB) interface. The acoustic signals, voice outputs, traffic information and display messages as part of the ETC and VICS functions are forwarded to the head unit via this connection. The head unit forwards the audio signals to the speaker system, except in the following cases:

 On vehicles with CODE 810 (Sound system), the head unit forwards the audio signals via MOST to the sound system amplifier control unit which actuates the speaker system.

 On vehicles with CODE 811 (Advanced sound system), the head unit forwards the audio signals via MOST to the Advanced sound system amplifier control unit, which actuates the speaker system.

 On AMG vehicles as of 01.06.2018 except code 810 (Sound system) and except code 811 (Advanced Sound System), the head unit forwards the audio signals via MOST to the Midline sound system amplifier control unit, which actuates the speaker system.

The Audio/COMAND display receives the picture signals for the display messages from the head unit via a high speed video link line.

In the following cases, an ETC message is output over the speaker system and at the same time shown on the Audio/COMAND display:

 ETC card not inserted.

 ETC card read error

 ETC card not accepted.

 ETC card reader error

 Fault in the communication with the tollbooth

 Detailed information about recent toll payments available.

 Payment completed successfully (beep)

In the following cases, the LED shows an error on the Dedicated Short-Range Communications control unit (LED flashes red):

 Invalid ETC card inserted

 ETC card not inserted correctly

 Malfunction of the ETC card reader

 If an ETC card is inserted and the Dedicated Short-Range Communications control unit does not recognize an error, the LED is lit in green.