Audio System Description - Overview

Basic Configuration

The Audio and Visual system consists of a digital audio/video playback function, communication with the customer's device, and displaying the driver's support information.

Audio Unit

The audio unit acts as a processor which includes playback functions for the USB, Bluetooth^® audio, iPod for music, and an internal radio tuner or an external radio tuner that is controlled with digital communication. Select audio functions using the audio unit buttons, touch screen (touch the display directly to select items on the screen), or the audio remote switch (on the steering wheel).

There are two kinds of audio units according to a vehicle model:

	Display Audio Type (7-inch Screen)	Color Audio Type (5-inch Screen)
With Navigation	?	×
Without Navigation	?	?

Display Audio Type (7-inch Screen)

The audio unit exists as a Head Unit that controls external audio/visual system related devices which do not have an audio disc player and a control module. The center display unit is located on the front of the audio unit. An antenna for Bluetooth communication, and an antenna for wireless LAN communication are built into the audio unit. Audio, Navigation, HFL, and Telematics functions are installed in the audio unit as application software. As an advanced feature, smartphone linkage and video playback functions are available.

An audio unit with navigation function is referred to as an audio-navigation unit. This unit has a built-in gyro sensor and a navigation map data (refer to the Navigation System Overview).

The SD card is a storage media that saves the navigation map data. The audio-navigation unit and the SD card cannot be substituted separately because the SD card module is not a removable type.

Both the audio-navigation unit and the audio unit have a GPS antenna circuit. The GPS information is used for a function that needs vehicle location other than the navigation function.

For vehicles with Sirius XM^® radio, the XM receiver circuit is built into the audio unit circuit. The XM satellite/terrestrial signal is received by the dedicated XM antenna. The audio unit holds XM presets and settings even when the 12 volt battery is disconnected (AM/FM presets are stored in the tuner unit).

There are two audio systems available for the display audio type:

	The system with stereo amplifier: An external stereo amplifier 10 (12^) channel output, 9 (11^) speakers and a subwoofer are equipped. The audio unit outputs a digital audio signal to the stereo amplifier.
	The system without stereo amplifier: 8 speakers are equipped. In this case, a power amplifier is built into the audio unit.

*: 5-door

Fail-Safe Function

The audio unit performs a fail-safe control when the system detects an abnormal high temperature in the unit:

Built-in cooling fan on/off control: When the audio unit temperature is too high, the audio unit turns the cooling fan on until the temperature cools down.

Self-Diagnostic Function

The audio unit has a self-diagnostic function to check the failure of the audio unit or its connection. Additionally, the audio unit has original hard error codes that can be displayed on the diagnostic screen to identify the failure part.

Forced Rebooting Function

If the system is frozen and the screen does not respond, you can attempt rebooting the audio unit by pressing and holding the AUDIO POWER (

) button for 5 seconds.

Center Display Unit

The center display unit has a 7-inch WVGA color TFT LCD that is driven by IPS (In-plane Switching) system with an electrostatic capacitive touch panel. The surface of the display is given an anti-glare coating. This unit displays the navigation map, vehicle information, various menu screens, and a rearview or LaneWatch^* image, and can operate the audio, navigation, and HFL systems by touching the display. The HVAC information is displayed if the audio unit receives a feedback signal from the climate control unit via the B-CAN.

*: With LaneWatch

Controls

The center display unit turns on when the DISP CONT signal changes from OFF to ON (depends on the audio unit).

After turning the center display unit on, all the communication for mutual status uses the dedicated digital signal line (LVDS1).

The audio unit also communicates with the gauge control module using the dedicated digital signal line (LVDS2). Audio and visual system information shown to the multi-information display (MID) is sent to the gauge control module using the LVDS2 line.

Fail-Safe Function

The center display unit performs a fail-safe control when the system detects an abnormal high temperature in the unit:

	When the center display unit temperature rises over about 77 °F (25 °C), the display brightness dims gradually.
	When the center display unit temperature rises to 158 °F (70 °C), the display brightness dims to 75 % of normal brightness.
	When the center display unit temperature rises over 176 °F (80 °C) for 8 minutes, the center display unit sends the error status to the audio unit, displays an error message, and then the display back light turns off (the background system stays on).
	When the center display unit temperature drops to below 167 °F (75 °C), the display back light turns on and the display brightness returns gradually as the temperature drops.

Self-Diagnostic Function

The audio unit can check the center display unit status by performing the System Diagnostic Mode.

Electrostatic Capacitive Touch Panel

To use the touch screen, bring your finger close to the screen or gently touch it with your finger. The touch sensor senses the change of the electrical charge when your finger is close to the screen and detects the position of the electrical charge. Use only a gentle touch to select or move the screen image. A hard finger press is not necessary. The screen cannot sense your touch if you wear heavy gloves, use a fingernail, or a pen.

Color Audio Type (5-inch Screen)

The audio unit consists of a simple component which does not have an audio disc player and has a 5-inch VGA color TFT LCD panel. This screen is not touch sensitive. The screen displays audio and HandsFreeLink (HFL) information and is not a touch sensitive type. Additionally, the screen shows the rearview camera image when the transmission is shifted to the R position/mode. The audio panel has an illumination dimming function that is controlled by the B-CAN information. An antenna for Bluetooth communication is built in the audio unit. As an advanced feature, the HFL function includes an external microphone that located in the roof console.

The AM/FM (RBDS) radio tuner is built into the audio unit, and can hold the AM/FM presets even when the 12 volt battery is disconnected.

Fail-Safe Function

The audio unit performs a fail-safe control when the system detects an abnormal high temperature in the unit:

	When the surface of LCD temperature rises over 194 °F (90 °C), the display back light turns off.
	When the surface of LCD temperature drops to below 189 °F (87 °C), the display back light turns on.

Self-Diagnostic Function

The audio unit has a self-diagnostic function to check the failure of the audio unit or its connection.

Audio System Functions

Anti-Theft Function

The audio unit has an anti-theft protection function separate from the security system of the vehicle. If the audio unit is removed from the vehicle, the audio unit requires a procedure to unlock the security system in order to use it again after the audio unit is reconnected.

There are two kinds of anti-theft mode release procedures:

	While displaying the security code entry screen or the conformation screen of the anti-theft system, press and hold the AUDIO POWER () button for at least 2 seconds. The audio unit automatically exits the anti-theft mode.
	While displaying the security code entry screen, enter the 5-digit anti-theft code.

The System Diagnostic Mode (includes checking hard error codes) can be used even if the audio unit is in the anti-theft mode.

If you substitute the audio unit into another vehicle, you must either enter the anti-theft code or perform the anti-theft skip mode in the System Diagnostic Mode (this mode will release the anti-theft code for 150 seconds).

Muting Logic

The outline of the audio interruption function is shown in the following table.

With Stereo Amplifier

Contents	Audio Output
Contents	Center CH	Left Front CH	Right Front CH	Right Rear CH	Left Rear CH	Subwoofer CH
System beep	Audio	Beep and audio	Beep and audio	Audio	Audio	Audio
Pressing TALK/BACK buttons	Feedback output	Muted	Muted	Muted	Muted	Muted
Guidance	Guidance output and attenuated audio	Attenuated audio	Attenuated audio	Attenuated audio	Attenuated audio	Attenuated audio
HFL	Muted	HFL output	HFL output	Muted	Muted	Muted
HFL and Guidance	Guidance output	HFL output	HFL output	Muted	Muted	Muted

Without Stereo Amplifier

Contents	Audio Output
Contents	Left Front CH	Right Front CH	Right Rear CH	Left Rear CH
System beep	Beep and audio	Beep and audio	Audio	Audio
Pressing TALK/BACK buttons	Feedback output	Muted	Muted	Muted
Guidance	Guidance output and attenuated audio	Attenuated audio	Attenuated audio	Attenuated audio
HFL	HFL output	HFL output	Muted	Muted
HFL and Guidance	Guidance output	HFL output	Muted	Muted

Speed-Sensitive Volume Compensation (SVC)

All audio systems are equipped with speed-sensitive volume compensation (SVC). The audio unit receives the vehicle speed pulse (VSP) from the gauge control module (B-CAN). The system processes the speed input and increases the audio system volume level as the vehicle speed increases to compensate for the interior noise that occurs at higher speeds. When the vehicle slows down, the volume returns to its normal level. For vehicles with a stereo amplifier, SVC function is controlled by the stereo amplifier. The SVC has four settings: SVC OFF, SVC LOW, SVC MID, and SVC HIGH that can be adjusted using the audio unit.

Operation Restriction

The audio unit has a function that restricts certain operations of audio and visual systems that may affect safe driving.

Clock Function

The audio unit has a real time clock circuit that operates the clock even if the vehicle is in the OFF (LOCK) mode. Also, the display audio type audio unit can adjust the internal clock by linking a smartphone. Additionally, the audio unit with a GPS antenna can display clock information by receiving the GPS signal.

USB Connection

For vehicles with an audio unit (display audio type), two USB ports are equipped for an external device input and a smartphone connection. USB port A is based on the specification of USB Battery Charging 1.2 (BC 1.2) that supports high-speed charging of the USB device. The audio unit can detect the USB device type (BC 1.2 or not) and change the charging mode automatically. USB port B supports charging to USB devices by a 1.0 A electrical supply.

For vehicles with an audio unit (color audio type), a USB port is equipped for an external device input. The USB port supports charging to USB devices by a 1.0 A electrical supply.

USB Audio

The audio system can play digital music from portable audio players, a USB drive, etc. When the device is plugged into the vehicle's USB port, and the vehicle is turned to the ACCESSORY mode, the audio unit begins to communicate with the connected USB device and supplies the VBUS power. The audio unit controls the device when searching and playing the files. Not all players and player functions work with the USB adapter. Please see the Owner's Manual for more information.

Supported Devices

	USB Mass storage class and Bulk-only transport are supported.
	USB 2.0 Full-speed capable.
	At least 256 MB storage capacity.
	USB formatted to be compatible with Windows-based operating systems.
	If the USB has a security feature, like write protection, it must be turned off.

There are many different USB devices, manufacturers, and configurations with new devices being released every day, which makes it impossible to test all USB devices with the audio system. Even if the USB device has all these requirements, it may not be compatible.

Hard drives do not support overwriting the data for the track order, which is why they are not recommended.

When you disconnect a USB device, the data for the track order remains in the audio unit's memory so when you reconnect the same USB device, the audio unit continues playing from the location where it was disconnected. If a new USB device is connected, the data for the track order is rewritten and you need to select the album or music file.

Bluetooth^® Connection

The audio unit can be paired with a compatible cell phone or a device for Bluetooth communication. Pairing procedures vary by the connection history and Bluetooth version of the cell phone or the device. Refer to the Owner's Manual.

The audio unit supports Bluetooth Ver 4.0+EDR (Ver 2.1+EDR^*). Bluetooth enables audio streaming, wireless play back on an audio device, hands-free calling with a cell phone, data communication, and phone book loading.

*: Color audio type

Bluetooth^® Audio

Bluetooth audio allows compatible Bluetooth cell phones equipped with music function to play music via the vehicle's audio system using Bluetooth technology. You can control the cell phone's music player remotely using the wireless connection.

	You can play music stored in your cell phone using the wireless connection.
	You can choose the next song, a previous song and resume/pause via the wireless connection.

NOTE: Not all cell phones support the Bluetooth audio function.

Supported Devices

	Bluetooth music phones that support A2DP 1.2 and AVRCP 1.0, 1.3, and 1.4.
	Bluetooth adapters for portable music devices including iPod are not supported.

NOTE: Availability of the functions depends on the connected cell phone.

Wireless LAN Connection (Display Audio Type)

The audio unit supports wireless LAN connection based on the IEEE 802.11 a/b/g/n standard. The audio unit can connect the device that has a function as a Wi-Fi access point.

Video Playback Function (Display Audio Type)

The audio system can play digital compressed video (MP4 is supported) from a USB device.

HD Radio^(TM) (Display Audio Type)

HD Radio^(TM) is a crystal clear digital audio broadcast by local radio stations. There is no charge for HD radio. Simply tune to your favorite station, and if the station is broadcasting with HD Radio^(TM) technology, then the audio unit will automatically pick up the digital signal, and begin playing the crystal clear, subscription free audio. Refer to your Owner's Manual to determine how your particular receiver indicates HD Radio^(TM) reception and how to transition from the main program to the multicast program(s).

	The HD1 channel acquires the analog station first and then blends with the digital signal. Therefore, the digital audio may have a short delay.
	There is no analog signal available on the HD2/HD3 channels. Therefore, there is a short delay while decoding the digital audio. The audio will begin playing when available.
	Go to www.hdradio.com for stations in the area to verify correct operation on the station.

Song By Voice^(TM) (Display Audio Type)

A customer can use the Song By Voice^(TM) feature to select and play the audio files in an iPod or a USB device with voice commands.

When an iPod or a USB device is connected to the audio unit, the unit makes a dictionary from the album name, folder name, artist name, track name, and the file name.

If a different device is connected, or the customer updates the files on the connected device, a new dictionary is created.

Internet Radio (USA models with Display Audio Type)

The audio system includes Pandora^® application installed in the audio unit as separate audio sources. The audio unit uses the customer's smartphone data connection to access the Pandora^® server, and transmits the internet radio data to the audio unit via the USB or the Bluetooth.

Smartphone Linkage Function (Display Audio Type)

This function helps ensure the safe use of a smartphone while driving. Connect a smartphone to the audio unit to use it. Connection methods vary depending on carriers.

When using the navigation function via a smartphone, the audio unit can display the navigation map screen that is in the connected smartphone. In this case, the GPS signal is received by the audio unit, and the vehicle signals are received from the F-CAN and the B-CAN as information of vehicle position tuning.

When using the voice recognition function via a smartphone, the HFL microphone in the roof console picks up the driver's voice, and sends the voice signal to the smartphone via the audio unit using Bluetooth.

When the voice recognition is in use, the audio unit sends the fan mute signal to the climate control unit via the B-CAN. The blower fan operating voltage may be reduced depending on the current fan speed.

HondaLink^® Assist (USA and Canada models Display Audio Type)

HondaLink^® delivers remote services to the vehicle using the customer's compatible Bluetooth cell phone.

If the SRS airbag is deployed, the SRS unit sends a signal to the audio unit via the F-CAN. Then, the audio unit calls a Public Safety Answering Point (PSAP) automatically using the customer's compatible Bluetooth cell phone and sends the vehicle location using Dual-Tone Multi-Frequency (DTMF). The audio unit uses the GPS antenna for tracking the vehicle location.

Tuner Unit

The tuner unit is a separate digital radio tuner interface for the display audio type audio unit. Received AM/FM radio waves are processed on the digital signal processor (DSP) and sent to the audio unit via the dedicated digital audio line (SPDIF1). At this time, HD radio^(TM) sound signal is separated from normal AM radio sound signals. All of the information about AM/FM reception (includes RBDS information) are sent from the tuner unit via the dedicated serial bus (RS485). The unit holds AM/FM radio frequency presets even when the 12 volt battery is disconnected.

For vehicles with Sirius XM^® radio, the antenna for receiving AM/FM radio waves and satellite/terrestrial (XM) signal uses a roof antenna type. AM/FM radio wave is amplified by the AM/FM antenna amplifier. The sensitivity of the FM wave is raised by the auto gain control. The XM antenna receives satellite signals and terrestrial signals by using the high-gain antenna. Signals are sent to the audio unit via the dedicated single line (SAT/TER).

Window Antenna Type

Roof Antenna Type

Self-Diagnostic Function

The audio unit can check the tuner unit status by performing the System Diagnostic Mode.

Stereo Amplifier

The stereo amplifier is a separated power amplifier interface. Digital audio signal (SPDIF2) that is received from the audio unit is processed on the DSP, and sent to each speaker after amplified by the AMP IC.

The stereo amplifier communicates with the audio unit using the dedicated serial bus (RS485). This communication includes the vehicle speed (for SVC) information, audio settings, and the MUTE commands. The stereo amplifier adjusts the speaker outputs which is based on the received information.

The stereo amplifier receives the active sound control signal, guidance signal, and the system beep signal via independent lines and mixes them to applicable audio lines.

2/4-door

5-door

Fail-Safe Function

The stereo amplifier performs a fail-safe control when the stereo amplifier detects an abnormal high temperature. The stereo amplifier then sends the error status to the audio unit, and the center display unit displays an error message which then the stereo amplifier inhibits sound output.

When the temperature cools down, the stereo amplifier outputs sound again.

Active Sound Control

The active sound control is the next generation of eliminating unwanted sound in the vehicle's cabin. The active sound control unit receives the engine speed pulse (NEP) from the F-CAN bus for adding sine wave signal to the engine sound to provide various levels of sound control depending on changes in the engine revolution. The active sound control unit controls the cabin sound up to engine speed about 8,000 (9,000^*) rpm.
*: Type-R

Audio Remote-HFL Switch

There are two kinds of audio remote-HFL switches according to a vehicle model:

	With multi-information display (MID): The audio remote switch and the HFL switch are integrated into the audio remote-HFL switch that uses the digital communication (LIN). For some models, the audio remote-HFL switch has an electrostatic capacitance touch sensor (see Center Display Unit for specific button operation).
	Without multi-information display (MID): The audio remote switch and the HFL switch are integrated to the audio remote-HFL switch that uses the resistor divider circuit.

When using any buttons or the touch switch on the audio remote-HFL switch, the control signal is sent to the audio unit via the gauge control module. The gauge control module reflects the control information of the audio remote-HFL switch as indication to the MID.

If the LIN circuit is open or shorted between the gauge control module and the audio remote-HFL switch, the gauge control module detects the related DTC.

With Multi-Information Display (MID)

Multi-View Rearview Camera

The multi-view rearview camera is a function that provides three different views to the driver by the camera that is installed at the rear of the vehicle. The view images can be changed by the user. The rearview guidelines change according to the selected view. The rearview camera is connected directly to the audio unit.

	Normal View Mode The display shows the standard view.
	Wide View Mode The display shows wider visibility than the normal view, which helps the driver confirm objects approaching from right and left.
	Top Down View Mode The display shows the view from the top angle of the vehicle, which helps the driver confirm the distance from an object behind.

Basic Control

The audio unit outputs the power source (CAMERA VCC) to the rearview camera under some conditions:

Turn the vehicle to the ACCESSORY mode.

?	If the audio unit does not detect the BACK LT signal for 5 minutes, the audio unit cancels outputting the power source to the rearview camera.

Detecting the BACK LT signal (when the transmission is shifted to R position/mode).

?	If the audio unit does not detect the BACK LT signal for 5 minutes after cancelling the rearview mode, the audio unit cancels outputting the power source to the rearview camera.

When using the Rear Camera diagnosis in the System Diagnostic Mode.

?	If the audio unit does not detect the BACK LT signal for 5 minutes after exiting the diagnosis, the audio unit cancels outputting the power source to the rearview camera.

When the audio unit detects the BACK LT signal for at least 0.3 seconds, the audio unit display turns on the rearview camera image. The display delays for 0.3 seconds to prevent changing the screen image too frequently because of incorrect shift position/mode selection. You can change the view mode by touching the mode icon^*1 or by pressing the SELECTOR knob^*2.

*1: Display audio type

*2: Color audio type

While displaying the rearview image, the LaneWatch function can not be used because the LaneWatch image is misunderstood as the rearview image.

Guidelines Type A

Guidelines Type B

Changing Camera Views

When the rearview camera image is displayed, touching the mode icon sends a signal from the audio unit to the rearview camera using the CAMERA BIT0 and CAMERA BIT1 signal lines to change the rearview camera view.

	Wide	Normal	Top Down
CAMERA BIT0 Signal	OFF (0 V)	ON (5 V - 8 V)	OFF (0 V)
CAMERA BIT1 Signal	OFF (0 V)	OFF (0 V)	ON (5 V - 8 V)

View Mode Memorization

The audio unit maintains the last view mode for 10 seconds after you shift the transmission to other than R position/mode. After that, the audio unit maintains last view mode (only wide view and normal view) even if the vehicle turned to the OFF (LOCK) mode. The rearview camera image will change to wide view if you had the top down view selected when you turn the vehicle to the OFF (LOCK) mode.

Dynamic Guideline (Display Audio Type)

When the rearview image is displayed with the guideline, the guideline changes according to the steering angle input (when the steering rotates 90 degrees or more). The steering angle information is received from the gauge control module via the B-CAN as vehicle signals.