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Mobile Phone System, Function - GF82.70-P-0007FH

Model 238 

Up To Model Year 2019 

G15467098Courtesy of MERCEDES-BENZ USA

Shown On Model 238 

Function requirements for mobile phone system, general 

IMPORTANT If a smartphone is integrated in the vehicle using Android Auto, telephone calls can only be made via the connected smartphone.

IMPORTANT Additional information available at: http://www.mercedes-benz.com/connect 

Mobile telephone system, general 

A differentiation is made between the following equipment and utilization variants in the mobile phone system:

IMPORTANT The mobile phone system is described here using basic telephony as an example. The special considerations for telephony with special equipment are summarized at the end of this document.

IMPORTANT A mobile phone authorized on the head unit can also be used as a playback device as part of Bluetooth® audio.

IMPORTANT Model 238

up to model year 2019

with code 520 (Audio 20 USB)

Model 238

up to model year 2019

with code 522 (Audio 20 radio)

except code 494 (US version)

Model 238

up to model year 2019

with code 531 (COMAND APS)

except code 360 (HERMES UMTS)

except code 362 (HERMES LTE)

A mobile phone authorized on the head unit can also be used as a modem to access the Internet.

The head unit sends and receives telephone signals over the Bluetooth® antenna. The head unit generates the display messages and sends them over an HSVL line to the Audio/COMAND display. Individual telephone functions can also be used via the instrument cluster. The head unit and instrument cluster exchange the required data via the user interface CAN.

The mobile phone system includes the following areas:

Bluetooth® 

Using Bluetooth®, it is possible to quickly and easily connect mobile terminals that support the corresponding profiles to the mobile phone system. Bluetooth® is a worldwide open standard for connecting Bluetooth® devices (e.g. mobile phone) wirelessly and is based on radio technology in the 2.4 GHz range. One advantage of Bluetooth®, in addition to the wide availability of Bluetooth® devices, is the uncomplicated and spontaneous connection of Bluetooth® devices. The extremely high data security (128-bit encoding) and the relatively limited radius (approx. 10 m) of this type of Bluetooth® network are what makes the use of Bluetooth® in the vehicle interesting. The head unit can integrate mobile phones into the vehicle hierarchy over the mobile phone's Bluetooth® interface and the Bluetooth® antenna. The head unit automatically searches for the last two connected mobile phones and connects to the mobile phone that responds first.

IMPORTANT If the mobile phone is not automatically connected to the head unit or if the head unit is to be establish a connection to another mobile phone, then the connection must be made manually over the telephone base function. Authorized telephones can be selected from a list. Non-authorized telephones must be authorized first. Up to 15 mobile phones can be authorized at the same time. If a new telephone is to be authorized when 15 telephones are already authorized, the user is prompted to delete one of the existing data records. Detailed information on authorization is available in the respective operator's manual.

Switch on/off characteristics 

A mobile phone operated via Bluetooth® is switched on and off on the mobile phone itself. The SIM PIN prompt (subscriber identification module, personal identification number), if configured on the mobile phone and if it is transmitting the status, occurs on the mobile phone only and the PIN has to be entered into the mobile phone. After logging into the mobile telephone network provider's network, the mobile telephone network provider and the signal level are displayed in the status bar of the Audio/COMAND display.

The switch-off signal via the mobile phone button is processed internally in the mobile phone. If the rechargeable battery of the mobile phone is empty, the mobile phone is also switched off. This process also runs internally in the mobile phone. The "Ready for Bluetooth® telephony" message appears on the Audio/COMAND display and the system automatically searches again for the mobile phones used most recently.

The head unit can be switched on and off with the "ON" button on the left lower control panel (with manual transmission) or on the right lower control panel (with automatic transmission). The control signal for the "ON" button is sent via the following route:

LCP LIN →

Audio/COMAND control panel →

Telematics CAN →

Head unit

Call signal 

The head unit receives the call signal over the Bluetooth® antenna from the mobile phone. The head unit sends the ringing tone either directly to the speaker system, on vehicles with code 810 (Sound system) via MOST to the sound system amplifier control unit or on vehicles with code 811 (Advanced sound system) via MOST to the Advanced sound system amplifier control unit. If the mobile phone supports "In-band ringing", the mobile phone ring tone is emitted over the speakers, otherwise the head unit's default ringing sound is used.

IMPORTANT The head unit mutes the currently active audio source (e.g. during radio mode) (mute function) and displays the caller ID over the HSVL line on the Audio/COMAND display.

Establish, end, accept, reject or toggle call 

Telephone numbers can be entered using a character bar on the Audio/COMAND display or they can be searched for and selected in call lists or in the address book. The mobile phone system can be operated using the following components:

IMPORTANT Toggle: If during a telephone call another incoming call is received or another telephone connection is set up, then the new call is activated and the existing one put on hold. It is then possible to switch (toggle) between the active call and the one on hold.

IMPORTANT Conference connection: If the mobile phone supports the function, it is possible - after several calls have been connected - to switch, not only between the calls, as for toggling, but to have all the calls active at the same time in a conference connection.

Mobile phone 

The mobile phone control is processed internally, status changes are received by the head unit over the Bluetooth® antenna.

Upper control panel control unit (With Code 246 (Analog clock)) 

The Telephone menu can be called up on the upper control panel control unit. The control signal is transferred as follows:

LCP LIN →

Audio/COMAND control panel →

Telematics CAN →

Head unit

Audio/COMAND control panel 

The Audio/COMAND controller is used to call up and activate the functions in the Telephone menu. The "Back" button supports navigation in the menus.

The control signals from the Audio/COMAND control panel are forwarded to the head unit via telematics CAN.

Touchpad (With Code 448 (Touchpad)) 

The head unit receives the control signals from the touchpad via the telematics CAN.

Multifunction steering wheel button groups 

The control signals from the multifunction steering wheel button groups are forwarded over the following components:

Steering wheel electronics →

Steering LIN →

Steering column tube module control unit →

Chassis FlexRay →

Electronic ignition lock control unit →

User interface CAN →

Head unit

Voice control system (VCS [SBS]) (With Code 531 (COMAND APS)) 

The voice control system is activated on the head unit multifunction steering wheel button group. When a call is being connected or a call being accepted, the voice control system is automatically switched off.

The control signal from the head unit multifunction steering wheel button group is forwarded over the following path:

Steering wheel electronics →

Steering LIN →

Steering column tube module control unit →

Chassis FlexRay →

Electronic ignition lock control unit →

User interface CAN →

Head unit

When the voice control system is active, the voice commands are recorded by the driver hands-free system microphone and forwarded via a direct line to the head unit. If necessary, the head unit sends the control signals over the Bluetooth® antenna to the mobile phone.

IMPORTANT The individual voice commands are listed in the "Linguatronic operator's manual".

Using the phone in hands-free mode 

The voice input in the hands-free mode is recorded by the driver hands-free system microphone and the front passenger hands-free system microphone, and forwarded to the head unit. The head unit sends the signals over the Bluetooth® antenna to the mobile phone. The head unit receives the incoming signals over the Bluetooth® antenna from the mobile phone and emits them at the speaker system. In vehicles with code 810 (Sound system), the head unit forwards the incoming voice signals via MOST to the sound system amplifier control unit and on vehicles with code 811 (Advanced sound system), to the Advanced sound system amplifier control unit, which amplifies the signals and sends them to the speaker system. The volume of the voice output can, e.g. be adjusted using the volume control button on the left lower control panel (with manual transmission), the right lower control panel (with automatic transmission) or the volume control button of the instrument cluster multifunction steering wheel button group.

Address book 

The user can manage all the contact data in the address book (view, edit, add, delete and create). The address book contains the address entries stored in the head unit. Address entries can only be removed by deleting individual entries or by deleting the entire address book. Address-relevant mobile phone system applications can be directly started and supplied with the stored data via address book entries. Address data from external devices (e.g. PDA or notebook) and storage media (e.g. SD (Secure Digital) card or USB (Universal Serial Bus) stick) can be stored in the address book and are then permanently available as an address entry. The address data can be sent to the address book via the following system components:

The head unit receives address data transferred via Bluetooth® from the Bluetooth antenna®. Address data from the multimedia connection unit or from the front center console USB port (with code 896 (Vehicle access and drive authorization via mobile phone), code 897 (Wireless mobile phone charging) or code 899 (Multifunction telephony)) is received by the head unit via a direct line.

Address book entries can contain the following information among other things:

IMPORTANT Model 238

up to model year 2019

with code 498 (Japanese version)

The call can be established via the voice control system for each entry with a completed "Yomigana field".

Short Message Service (SMS) (Except Code 498 (Japan version)) 

The user can receive, send and manage SMS messages (e.g. read or delete them). For this purpose, the SMS messages previously received on the mobile phone as well as all new SMS messages are forwarded to the head unit. The following SMS functions are possible:

IMPORTANT The SMS function with basic telephony requires the Message Access Profile (MAP) to be supported. Under certain circumstances, loading SMS messages may take a long time. This may be because of the mobile phone or the number of SMS messages in the mobile phone.

As soon as the head unit is connected to the mobile phone, it starts to receive the SMS messages already stored on the mobile phone and any new incoming SMS messages via the Bluetooth® antenna from the mobile phone. The functions for writing, sending and managing SMS messages are activated through the basic telephone function. The head unit shows the telephone menu via the HSVL line on the Audio/COMAND display. When the SMS is being read out, the head unit sends the audio signals either directly to the speaker system or via MOST to the sound system amplifier control unit (with code 810 (Sound system)) or the Advanced sound system amplifier control unit (with code 811 (Advanced sound system)).

Telephony With Code 379 (Telephone module with Bluetooth® (SAP profile)) 

The mobile phone signals are sent and received over the left telephone antenna or right telephone antenna. The connection is made via the telephone antenna splitter and the mobile phone contact plate in the center console under the armrest. The telephone module with Bluetooth® (SAP profile) is connected to the mobile phone contact plate.

IMPORTANT The mobile phone system does not support the Long Term Evolution (LTE) cellular telephone system standard.

IMPORTANT The telephone module with Bluetooth® (SAP) supports the SIM Access Profile (SAP), the Message Access Profile (MAP) and the Phonebook Access Profile (PBAP).

Telephony with CODE 379 (Telephone module with Bluetooth® (SAP profile)) exhibits the following special considerations:

Telephone module with Bluetooth® (SAP profile) 

The telephone module with Bluetooth® (SAP profile) can be used in two different ways to make a call:

Mobile phones that are to be used for telephony with the telephone module with Bluetooth® (SAP profile), must support the SIM Access Profile and be connected once (authorized) to the telephone module with Bluetooth® (SAP profile). Up to 15 mobile phones can be authorized as SAP telephones at the same time. After switching on the head unit, an automatic search is performed for the last two SAP telephones used in the vehicle, and the first one that responds to the prompt is connected, when the following conditions are given:

If another SAP telephone is to be connected, then the connection has to be interrupted first and then the corresponding SAP telephone manually connected by selecting it from the list of SAP telephones.

IMPORTANT If necessary, the SAP telephone can be charged using a USB connector on the telephone module with Bluetooth® (SAP). A second USB connector on the telephone module with Bluetooth® (SAP) is used to realize the data transfer over the multimedia connection unit to the head unit.

IMPORTANT The telephone module with Bluetooth® (SAP profile) is Internet capable when the mobile phone contract includes a data option.

IMPORTANT A ring tone can be selected for the respective SIM card or SAP telephone from a list of ring tones.

Mobile phone contact plate functions 

The mobile phone contact plate fulfills the following functions:

IMPORTANT The connection to the head unit (over Bluetooth®) is made using the telephone module with Bluetooth® (SAP).

signal curve 

The mobile phone signals are received from the mobile telephone network as follows:

Left telephone antenna or right telephone antenna →

Telephone antenna splitter →

Telephone and Remote Parking Pilot/stationary heater antenna changeover switch (model 238.4 with code 228 (Stationary heater) or with code 503 (Pre-installation for Remote Parking Pilot)) →

Mobile phone contact plate →

Telephone module with Bluetooth® (SAP profile)

The telephone module with Bluetooth® (SAP) can forward the telephone signals to the head unit over two different routes:

Switch-on characteristics 

The mobile phone system is automatically switched on by a wake-up pulse when the head unit is switched on. The head unit sends the signal over a direct line to the mobile phone contact plate. The mobile phone contact plate forwards the signal to the telephone module with Bluetooth® (SAP).

PIN prompt 

After the SAP telephone is switched on, the PIN is queried if the SAP telephone is configured for this. The PIN prompt is shown by the head unit over HSVL line on the Audio/COMAND display. The PIN can be entered using the head unit controls. The PIN of a connected telephone or the SIM card can be saved by the telephone module with Bluetooth® (SAP) so that it does not need to be entered again when switched on.

SMS 

State of the art mobile phones come with two memories for SMS messages: one on the telephone and one on the SIM card. As long as the mobile phone is used as an SAP phone for telephony with code 379 (Telephone module with Bluetooth® (SAP)), incoming SMS messages on the mobile phone can only be stored on the SIM card.

Storing incoming SMS messages on the SIM card can lead to the following problems:

Telephony With Code 386 (Comfort telephony) 

The mobile phone system is automatically switched on by a wake-up pulse when the head unit is switched on. If a mobile phone is inserted in the universal smartphone cradle (in the stowage compartment under the armrest), it can send and receive mobile phone signals via the left and right telephone antenna. The mobile phone is connected to the head unit via the Bluetooth® antenna.

The mobile telephone network signals are received as follows:

Left telephone antenna and right telephone antenna →

Telephone antenna splitter →

Telephone and Remote Parking Pilot/stationary heater antenna changeover switch (model 238.4 with code 228 (Stationary heater) or with code 503 (Pre-installation for Remote Parking Pilot)) →

Cellular telephone system antenna amplifier/compensator →

Mobile phone contact plate →

Universal smartphone cradle →

Mobile phone →

Bluetooth® antenna →

Head unit

IMPORTANT An antenna for inductive transmission of the telephone signals to the mobile phone is integrated in the universal smartphone cradle. The mobile phone is not charged by the universal smartphone cradle. For charging purposes, the mobile phone can be connected via a cable to the multimedia connection unit.

Telephony With Code 899 (Multifunction telephony) 

The mobile phone signals are sent and received over the left telephone antenna or right telephone antenna. The connection is made via the telephone antenna splitter, cellular telephone system antenna amplifier/compensator and the mobile phone cradle control unit in the center console. For communication via the antenna connection (and for charging), the mobile phone is placed onto the mobile phone cradle control unit.

IMPORTANT If the mobile phone does not support the Qi standard for wireless charging, it can be connected to the front center console USB port for the charging process using a charging cable included in the package contents.

IMPORTANT The mobile phone system supports the Long Term Evolution (LTE) mobile radio standard.

Telephony with code 899 (Multifunction telephony) exhibits the following special features:

Functions of mobile phone cradle control unit 

The mobile phone cradle control unit fulfills the following functions:

IMPORTANT The connection to the head unit (via Bluetooth®) is made via the mobile phone.

signal curve 

The mobile phone signals are received from the mobile telephone network as follows:

Left telephone antenna or right telephone antenna →

Telephone antenna splitter →

Telephone and Remote Parking Pilot/stationary heater antenna changeover switch (model 238.4 with code 228 (Stationary heater) or with code 503 (Pre-installation for Remote Parking Pilot)) →

Cellular telephone system antenna amplifier/compensator →

Mobile phone cradle control unit →

Mobile phone →

Bluetooth® antenna →

Head unit

Switch-on characteristics 

The mobile phone system is automatically switched on by a wake-up pulse when the head unit is switched on. The head unit sends the signal over a direct line to the mobile phone cradle control unit. The mobile phone cradle control unit routes the signal inductively to the mobile phone.

PIN prompt 

A prompt for the PIN is shown after switching on the mobile phone if the mobile phone is configured for this. The PIN prompt is shown by the head unit over HSVL line on the Audio/COMAND display. The PIN can be entered using the head unit controls.

Near Field Communication (NFC) 

The Near Field Communication is an international transmission standard for the wireless exchange of data via radio technology over very short distances of a few centimeters. Mobile phones that are placed on the mobile phone cradle control unit and that support the NFC standard can be connected easily and quickly using Near Field Communication to the mobile phone system. The NFC interface of the mobile phone cradle control unit and the near field communication antenna are used for near field communication. The mobile phone cradle control unit sends the initialization data via the telematics CAN to the head unit.

Additional function requirements for connection priority 

Connection priority 

The head unit can integrate authorized mobile phones over the Near Field Communication or through Bluetooth® into the vehicle hierarchy. Near field communication uses the NFC interfaces of the head unit and the mobile phone cradle control unit as well as the near field communication antenna on the mobile phone cradle control unit.

Bluetooth® communication uses the Bluetooth® interface of the mobile phone and the Bluetooth® antenna.

The head unit differentiates between the following connection priorities:

If there is no mobile phone on the mobile phone cradle control unit, the head unit automatically searches over the Bluetooth® connection for the last two connected mobile phones and then connects to the mobile phone that responds first (basic telephony).

  Electrical function schematic for mobile phone   PE82.70-P-2051-97DCA
  Overview of system components, telematics   GF82.85-P-9999FH 
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