Principles Of Operation

Information and Entertainment System

Principles of Operation

Audio Control Module (ACM)

The Audio Control Module (ACM) can be operated while the key is in RUN or ACC. Additionally, the one hour mode feature allows the audio system to be operated for 1 hour when the ignition is transitioned to OFF and the ON/OFF button is pressed.

The ACM can produce its own DTCs, which can be communicated to the scan tool. The ACM communicates on the Infotainment Controller Area Network (I-CAN), with the Front Control/Display Interface Module (FCDIM) acting as the gateway to the Medium Speed Controller Area Network (MS-CAN).

Front Controls Interface Module (FCIM)

The Front Controls Interface Module (FCIM) is the customer interface to the audio system. It is separate from the ACM, and utilizes a dedicated Local Interconnect Network (LIN) with the FCDIM to transmit button press information.

Front Control/Display Interface Module (FCDIM)

The FCDIM is a stand-alone module. It receives messages for all of its displays, which include:

- Audio information
- Warning and information messages

The FCDIM acts as the gateway between the MS-CAN and the I-CAN.

Satellite Audio

The satellite audio system consists of the ACM, the AM/FM/satellite radio combination antenna, and the antenna cables. The antenna receives digital audio signals and sends them to the ACM.

Antenna

The fixed-mast antenna receives AM/FM radio waves and sends them to the ACM via the antenna co-axial cable. If the vehicle is equipped with satellite audio, a combination AM/FM/satellite radio antenna is utilized.

The antenna receives voltage from the ACM in order to amplify the audio signals.

SYNC(R) System

The SYNC(R) system allows interaction with several types of customer devices, including mobile phones and media devices. The system is comprised of the Accessory Protocol Interface Module (APIM), a microphone, 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 2 internal modules: the Consumer Interface Processor (CIP) and the Vehicle Interface Processor (VIP). The modules are not replaceable individually, but can be flashed independently, if required.

The CIP interfaces with all of the customer inputs to the APIM. The CIP 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. The main functions of the VIP are controlling the APIM power management and translating both inbound and outbound signals over the CAN.

The APIM can receive inputs from the following 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.

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, pause, etc.) 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 any one time. If an additional device of either type is paired with the system and made active, the APIM disconnects any active connections 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 website .

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 metadata is used by the APIM to create indexes that can be used to sort for particular music, based on customer preference. Not all USB devices 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. This can take up to several minutes (depending on the amount of data on the device), 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), which reduces the amount of time needed to create the index.

The APIM receives both stereo and mono sound inputs, and can also transmit both stereo and mono sound. The mono function is used to receive the microphone input, and to send 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 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 (part of the e911 feature). The vehicle location information is broadcast to the APIM over the CAN.

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

Steering Wheel Controls

The steering wheel controls consist of a series of resistors. Each steering wheel controls switch function corresponds with a specific resistance value within the switch. When a switch is pressed, the FCDIM (or the APIM) monitors the change in reference voltage to determine the requested function.

On vehicles equipped with the SYNC(R) system, the PUSH-TO-TALK (an icon of a person speaking) switch interfaces directly with the APIM, while the other audio steering wheel controls interface with the FCDIM.

Audio Input Jack

The audio input jack allows for a portable MP3 audio device to be connected to the vehicle audio system. When a portable MP3 player is connected, audio from the MP3 audio device can be played through the vehicle speakers. The audio stream from the audio input jack routes to the APIM if the vehicle is equipped with the SYNC(R) system, or directly to the ACM if the vehicle is not equipped with the SYNC(R) system.

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. A 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.

A digital signal is used to transmit 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 is used to broadcast audio signals from a Bluetooth(R) device to the APIM. As with a digital signal sent through the USB port, the APIM converts the wireless audio signal to analog and relays it to the ACM.

Network Communication

There are numerous messages internal to the audio system. The functions of these message include (but are not limited to):

- Changing the audio source
- Updating the FCDIM display

In addition, the numerous messages are utilized by the audio system in conjunction with systems outside of the audio system. Refer to Module Communications Network Testing and Inspection for a complete list of network messages.