Principles of Operation

Information and Entertainment System

Principles of Operation

Audio Control Module (ACM)

The Audio Control Module (ACM) can be operated with the ignition in RUN or ACC. The accessory delay feature allows the audio system to be operated for a preset period of time after the ignition is turned off and a front door has not been opened. The ACM sends AC voltage audio signals to the speakers or to the amplifier, depending on vehicle configuration. The ACM can produce its own DTCs, which can be communicated to the scan tool through the Medium Speed Controller Area Network (MS-CAN).

Audio Control Module (ACM) Illumination

The base (AM/FM) ACM has a hardwired illumination circuit from the Body Control Module (BCM). For all other ACMs, the illumination signal is received via the MS-CAN.

Satellite Audio

The satellite audio system consists of a Satellite Digital Audio Receiver System (SDARS) module, a satellite radio antenna, and a satellite radio antenna cable. For early build vehicles without navigation, an external SDARS module is utilized. For late build vehicles and all vehicles with navigation, the SDARS module is built into the ACM. The satellite radio antenna receives digital audio signals and sends them to the SDARS module (early build vehicles without navigation) or to the ACM (all except early build vehicles without navigation).

Subwoofer

The premium audio subwoofer and amplifier are integral. The function of the enable/clip detection circuit is to turn the amplifier on and to indicate to the ACM when the subwoofer output distortion signal reaches a damaging level. The ACM then clips the audio output signal to prevent damage to the subwoofer.

Navigation System

The navigation system guides the user to a pre-entered destination. No navigation map DVD is needed, as the map guidance information is stored in the ACM. The ACM calculates route information based on Global Positioning System (GPS) data. The GPS antenna tracks several satellites simultaneously. The ACM also uses vehicle speed and transmission gear selected signals received through the MS-CAN to detect vehicle speed and direction, resulting in more accurate navigation tracking.

The navigation display is part of the ACM. Either the touchscreen or the buttons on the ACM can be used to interact with the navigation system.

The compass heading is derived from the GPS antenna signal. There are no serviceable parts for the compass.

A voice recognition system allows the user to interface with the system without using the touchscreen. A microphone located in the headliner provides a direct input to the ACM. The microphone is shared with the SYNC(R) system.

Jukebox Feature

The navigation ACM contains a 10 gigabyte on-board hard drive that is capable of storing music ripped (recorded) from a music disc. The music can be loaded into the jukebox by inserting a disc (in the correct format) and following the on-screen instructions to load the music into the ACM. The jukebox cannot rip MP3 discs.

SYNC(R) System

The SYNC(R) system allows interaction with several types of customer devices, including mobile phones and media devices. The system consists of the Accessory Protocol Interface Module (APIM), a microphone (located in the headliner), the Universal Serial Bus (USB) cable and port and the audio input jack. The APIM contains an on-board Bluetooth(R) chipset, which enables certain wireless devices to interact with the system.

The APIM consists of a Consumer Interface Processor (CIP) and a Vehicle Interface Processor (VIP). The modules are not replaceable individually, but can be flashed independently, if required.

The CIP interfaces with all of the inputs to the APIM. It contains an analog-to-digital-to-analog converter, as well as the Bluetooth(R) chipset. Any consumer-available application upgrades that are available are loaded directly to the CIP through the USB port.

The VIP provides an interface between the CIP and the vehicle. Its main functions are controlling the APIM power management and translating both inbound and outbound signals over the Controller Area Network (CAN). In addition, the VIP interrogates the modules on the network to retrieve any DTCs when a vehicle health report is requested.

The APIM can receive inputs from the following audio sources:

- USB port
- Audio input jack
- Bluetooth(R)

The USB port can be used for connecting a media device (such as an iPod(R)) with the device's available cable or for directly plugging in a portable mass storage device (such as a thumb drive). When playing media files stored on a mass storage device, the SYNC(R) system only plays files that do not have Digital Rights Management (DRM) protection. The USB port can also be used for uploading vehicle application upgrades.

The USB port is powered by the APIM, so no external power source is needed to power a device plugged into the USB port if the device supports this feature.

The audio input jack can be used for connecting a media device (such as an iPod(R)) utilizing a 1/8-inch audio jack. When a device is connected through the audio input jack, only the speaker volume can be controlled by the ACM. All other functions (such as seek, fast forward and pause) must be carried out on the device itself.

The Bluetooth(R) interface can accommodate both Bluetooth(R)-enabled mobile phones and Bluetooth(R)-enabled media devices. Any Bluetooth(R) device used with the SYNC(R) system must first be paired with the system before it is operational.

Bluetooth(R) is a secure, short-range radio frequency that allows devices to communicate wirelessly through radio waves. The operating range of a Bluetooth(R) signal is a maximum of 32 feet.

Only one Bluetooth(R) phone and one Bluetooth(R) media device can be connected to the system at a time. If an additional device of either type is paired with the system and made active, the APIM disconnects any active connection and establishes a connection with the new device.

It is important to understand that not all mobile phones have the same level of features when interacting with the SYNC(R) system. For a list of compatible phones, refer to the SyncMyRide web site .

In addition to audio information, metadata may also be sent to the APIM from a device plugged into the USB port. Metadata consists of such information as artist, album title, song title and genre. The APIM uses the metadata to create indexes that can be used to sort for particular music, based on customer preference. Not all USB devices can send metadata to the APIM; also, no metadata is transferred when a device is connected through the audio input jack. When a new media device is connected to the SYNC(R) system, the APIM automatically indexes the information. Depending on the amount of data on the device this may take up to several minutes and is considered normal operation. When a device that was previously connected to the SYNC(R) system is reconnected, the APIM updates the index (rather than creating a new one), reducing the amount of time needed to index the device.

The APIM receives both stereo and mono sound inputs and can also transmit both stereo and mono sound. The mono function receives the microphone input. It also sends sound to the ACM for voice prompts, the Text-To-Speech (TTS) feature, ringtones and any audio received through a connected mobile phone. The TTS feature speaks information so that it does not have to be read from the display.

The APIM communicates on the MS-CAN and High Speed Controller Area Network (HS-CAN). Communication with the scan tool is established through the HS-CAN.

Global Positioning System Module (GPSM)

For vehicles equipped with SYNC(R) but not navigation, the Global Positioning System Module (GPSM) provides vehicle location for real-time traffic reports and re-routing, and for identifying vehicle location in the event of a collision. The vehicle location information is broadcast to the APIM over the MS-CAN.

Voice Recognition For Vehicles With Navigation And The SYNC(R) System

When the audio system enters voice recognition mode, the ACM initially controls the voice recognition feature. The microphone is wired directly to the APIM, which relays the microphone input to the ACM through dedicated wiring. If the first command spoken is part of the ACM voice recognition set, the ACM retains control of the voice recognition and takes the appropriate action(s). If the first command spoken is part of the APIM voice recognition set, the ACM shuts off its own voice recognition and broadcasts a Controller Area Network (CAN) message to the APIM, transferring the voice recognition to the SYNC(R) system and providing the voice command that was spoken. The ACM controls the voice engine for the base audio, navigation and climate control systems. The APIM controls the voice engine for the SYNC(R) system (USB port, audio input jack, and Bluetooth(R)).

AM/FM Antenna

A co-axial antenna cable connects the AM/FM antenna to the ACM.

Global Positioning System (GPS) Antenna

For vehicles equipped with navigation, the GPS antenna receives information from satellites. The compass heading is also derived from the GPS signal. A combination GPS/satellite radio is utilized.

Steering Wheel Controls

The steering wheel controls consist of a series of resistors. Each steering wheel control switch function corresponds with a specific resistance value within the switch. When a switch is pressed, the reference voltage from the switch changes. This voltage change is monitored by the Steering Column Control Module (SCCM), which determines the requested function. A message is then sent from the SCCM through the HS-CAN to the BCM. The BCM converts the high speed message to an MS-CAN message and sends it to the ACM (or APIM) over the MS-CAN.

Audio Input Jack

The audio input jack allows for a portable MP3 player to be connected to the vehicle audio system. When a portable MP3 player is connected, audio from the MP3 player can be played through the vehicle speakers.

Noise Suppression Equipment

The radio frequency suppression equipment reduces interference transmitted through the speakers by the engine ignition and electrical systems. When installing any new radio suppression equipment components, make sure that a good contact is made at all connections.

Audio Signals

Stereo signals contain left and right channel information and are used for most audio signals.

A mono signal is used for the microphone input to the APIM. The mono signal is also used for the voice prompts, the TTS feature, ringtones and any audio received through a connected mobile phone. These audio signals are output from the APIM to the ACM. The mono and stereo outputs from the APIM utilize separate circuits from the stereo output.

A digital signal transmits data from a media device connected through the USB port to the APIM. The APIM then converts the signal to analog and relays the signal to the ACM.

A wireless signal broadcasts audio signals from a Bluetooth(R) media device to the APIM, which converts the wireless audio signal to analog and relays it to the ACM.