Device and technical description of the audio system (Discovery 3)

Location of low-level audio components

Item name	Spare part number	Description
1	-	Audio Control Switches
2	-	Antennas in glass
3	-	Antenna amplifier
4	-	Rear LH speakers (left) doors
5	-	Front LH speakers (left) doors
6	-	Audio head unit
7	-	Movable contact group
8	-	Front RH speakers (right) doors
9	-	Rear RH speakers (right) doors

Audio head unit control circuit

NOTE: A = Wired

Item name	Spare part number	Description
1	-	ignition switch
2	-	Audio remote control
3	-	Movable contact group
4	-	Audio head unit
5	-	Speakers
6	-	Antenna amplifier
7	-	AM antenna (amplitude modulation) /FM (frequency modulation)
8	-	Fuse

The location of the elements of the audio system with a combined head unit (IHU)

Item name	Spare part number	Description
1	-	Audio remote control (second row of seats)
2	-	Tuner TMC
3	-	Audio remote control (third row of seats)
4	-	Antenna amplifier
5	-	AM antenna (amplitude modulation) /FM (frequency modulation) in the side window
6	-	Antenna booster tuning to the best station
7	-	SDARS / Roof Mounted Telephone Antenna Adapter
8	-	Antennas in tailgate glass
9	-	Subwoofer
10	-	Audio remote control (third row of seats)
11	-	Audio remote control (second row of seats)
12	-	midrange speaker
13	-	Tweeter (tweeter)
14	-	AV input/output panel
15	-	midrange speaker
16	-	Tweeter (tweeter)
17	-	Movable contact group
18	-	Audio remote control
19	-	Audio amplifier
20	-	Unified audio headunit (IHU)
21	-	midrange speaker
22	-	Tweeter (tweeter)
23	-	midrange speaker
24	-	Tweeter (tweeter)

Integrated head unit audio control scheme (IHU)

NOTE: A = Wired connection; P = MOST bus

Item name	Spare part number	Description
1	-	Accumulator battery
2	-	Infotainment system main relay
3	-	Audio remote control
4	-	Movable contact group
5	-	Audio remote control (second row of seats)
6	-	Audio remote control (second row of seats)
7	-	Audio remote control (third row of seats)
8	-	Audio remote control (third row of seats)
9	-	Unified audio headunit (IHU)
10	-	Tuner SDARS
11	-	Audio amplifier
12	-	SDARS / Roof Mounted Telephone Antenna Adapter
13	-	Speakers
14	-	Antenna amplifier in the side window tuning to the best station
15	-	AM antenna (amplitude modulation) /FM (frequency modulation) in the side window
16	-	Antennas in tailgate glass
17	-	Antenna amplifier in tailgate glass
18	-	AV input/output panel
19	-	Fuse 53p
20	-	Fuse link 18E

Audio Head Units

Cars can be equipped with a standard audio system or a premium audio system. The architecture of a standard audio system is built around a head unit that communicates with other nodes via the CAN bus (local area network of controllers) medium data rate, and a top-of-the-line audio system architecture around an integrated headunit (IHU), which communicates with other nodes over the network of the data transmission system for media systems (Media Orientated System Transport - MOST) and CAN bus (local area network of controllers) average data rate.

Standard audio headunit

The head unit of the standard audio system has the following components:

• Radio
• CD player (CD) on one disk
• Amplifier

The head unit communicates with other vehicle systems via the CAN bus (local area network of controllers).

Connector contacts C1354 of the control unit of the standard audio system

contact no	Description	Input signal / output signal
1	"Weight" power circuit	-
2
3	(+) rear LH (left) dynamics	Output signal
4	(-) rear LH (left) dynamics	-
5	(+) rear RH (right) dynamics	Output signal
6	(-) rear RH (right) dynamics	-
7	The signal of the audio control switches located on the steering wheel	Input signal
8	Not used	-
9	(+) CAN bus input (local area network of controllers)	Input signal
10	(-) CAN bus output (local area network of controllers)	-
11	Battery voltage	Input signal
12	(+) antenna power supply	Output signal
13	(-) front LH (left) dynamics	-
14	(+) front LH (left) dynamics	Output signal
15	(-) front RH (right) dynamics	-
16	(+) front RH (right) dynamics	Output signal
17	Not used	-
18	(+) steering wheel audio controls reference voltage	Output signal
19	(+) CAN bus output (local area network of controllers)	Output signal
20	(-) CAN bus output (local area network of controllers)	-

The head unit has a power management function. If the battery voltage falls below a predetermined level, the unit restricts certain functions. The head unit receives CAN signals (local area network of controllers), which allow you to determine the need to turn on / off. The following describes the on/off conditions associated with the control of the ignition switch.

• If CAN bus activity is detected (local area network of controllers) and the battery voltage is greater than 12.3V, the LCD (liquid crystal display) head unit displays the clock.
• If the head unit is turned on while the ignition key is in the ignition switch and the switch is turned to the ACC/AUX position, the audio head unit will normally operate in power saving mode for 1 hour.
• If the key is turned from the ACC/AUX position to the IGN/RUN position, all head unit functions are still performed.
• If the key is turned from IGN/RUN to the engine start position, the sound is muted while the engine is cranking.
• If cranking is completed and the ignition key is returned to the IGN/RUN position, the head unit is in normal power mode.
• If the key is turned from the IGN/RUN position to the ACC/AUX position, the head unit enters power saving mode, limiting the output volume.
• If the key is moved from the ACC/AUX position to the off position, the head unit will operate in power saving mode for 10 minutes. After the specified time has elapsed, the head unit enters standby mode. If the key is not removed and the CAN network (local area network of controllers) goes into standby mode, the head unit turns off. The head unit will only turn on again when one of the following conditions is met: the door locks change from locked to unlocked, the ignition key is turned from off to the ACC/AUX position, the head unit power button is pressed, CD (CD) inserted or removed.
• When the key is removed, the head unit enters standby mode. The only exception is when the key is removed during a telephone conversation. Until the end of the conversation, the head unit remains on, and when it ends, it goes into standby mode.

All of the above power modes are based on receiving the status signals of the ignition switch via the CAN bus (local area network of controllers).

Transport mode

Transport mode is used to reduce battery drain while the vehicle is being stored or transported. Transport mode is started/switched off by T4 via CAN signals (local area network of controllers). In transport mode, the following circuits are disabled:

• Amplifiers
• External signal source and telephone
• Watch
• Antenna Power
• Power LED (Light-emitting diode)

In transport mode, only the circuits of the CAN connector work (local area network of controllers) and power switch.

CAN connector (local area network of controllers) remains open to receive an EXIT signal from transport mode. The power switch remains on to display on the LCD () head unit a message that the unit is in transport mode when you try to turn on the head unit. The message is displayed only if the vehicle is moving and the battery voltage is greater than 12.3 V.

Radio functions

The radio receiver is located in the head unit. The radio receiver is capable of receiving radio broadcasts in the AM and FM bands and memorizing 18 FM band stations and 12 AM band stations (amplitude modulation). AM band stations (amplitude modulation) are remembered as follows:

Saving Band Stations in Europe Models

• 6 MW
• 6 MWa
• 6 LW
• 6 LWa

Storing Band Stations in US Models

• 6 MW1
• 6 MW2
• 6 MWa

CD player features (CD)

The headunit contains a CD player with single CD playback capability (CD). This CD player (CD) has all the features common to all CD players (CD):

• CD playback (CD)
• Previous / next entry
• Playing Recordings in Random Order
• Loading / ejecting a CD (CD)
• Scanning a CD
• Repeat Play

Unified audio headunit

The head unit of the high-end audio system has the following components:

• Radio.
• CD player (CD) (with built-in six-CD changer).
• Built-in telephony controller.
• Additional input socket (for any device with 3.5mm plug).

Unified audio headunit (IHU) also integrated with the navigation system, which requires the installation of a navigation computer, touch screen and GPS antenna (global positioning system).

The IHU is turned on by a CAN bus signal (local area network of controllers), not when the ignition switch is turned to the AUX position.

The IHU is the main MOST bus subscriber and contains the MOST system synchronizer.

Connector contacts C1354 of the upper class audio system control unit

contact no	Description	Input signal / output signal
1	"Weight"	-
2	Not used	-
3	Not used	-
4	Not used	-
5	Not used	-
6	Not used	-
7	"Weight" steering wheel switches	-
8	Infotainment relay	Output signal
9	(+) CAN bus (local area network of controllers)	Input signal
10	(-) CAN bus (local area network of controllers)	Output signal
11	Battery voltage	Input signal
12	Antenna Power	Output signal
13	Not used	-
14	Not used	-
15	Not used	-
16	Not used	-
17	Not used	-
18	Reference voltage of steering wheel switches	Output signal
	(+) CAN bus (local area network of controllers)	Input signal
	(-) CAN bus (local area network of controllers)	Output signal

C2115 connector pin chart

contact no	Description	Input signal / output signal
1	Not used	-
2	Not used	-
3	(+) phone	Output signal
4	Not used	-
5	(-) phone	-
6	Additional screen	-
7	Right plug socket for connecting additional equipment	Input signal
8	Left plug socket for connection of additional equipment	Input signal
9	Not used	-
10	Not used	-
11	Not used	-
12	Mass of sound signals	-

Radio

The IHU contains an AM receiver (amplitude modulation) /FM (frequency modulation), which can store 18 FM stations (frequency modulation) and 12 - in the AM band (amplitude modulation) (6 in the medium wave range and 6 in the long wave range). The radio also has the following features:

• Automatic station tuning
• Receiving traffic messages (TA)
• RDS EON function (radio data transmission system)
• Search for stations
• Forward and Reverse Adjustment

CD player (CD)

The CD player is a built-in device that can hold 6 CDs (CD) . CD player (CD) can play commercial CDs (CD), CD formats (CD) R and CD (CD) RW and CDs with recordings in MP3 format.

Playing Recordings in Random Order

Random play only works on selected CDs (CD). When the random play function is enabled, all tracks on the selected CDs (CD) are played in random order. A new playback sequence is created only after all the tracks on the disc have been played. If a new CD is selected for playback (CD) in random play mode, random play mode is canceled and playback starts from track 1.

Repeat Play

The user can select the mode of cyclic repetition of playing the current audio track.

MP3

CD player (CD) Supports playback of MP3 files. This format allows you to group files into folders. It is also possible to place all files in the root directory of the CD (CD) .

Random and repeat functions work the same as regular CDs (CD) .

Scanning a CD

The CD Scan feature allows you to play the first 10 seconds of each CD track (CD), inserted into the block.

Automatic volume control (AVC)

Automatic volume control compensates for the increase in vehicle noise levels as vehicle speed increases.

There are 10 levels of AVC system setting: 0 - the system is off, 1 - the minimum increase in volume when increasing the speed of movement, and further up to 9 - the maximum increase in volume.

The IHU uses speed sensor signals to calculate the required volume change. The vehicle speed signal is received via the CAN bus (local area network of controllers) from the ABS control module (anti-lock braking system). The average of the four wheel speeds is used.

The AVC system is controlled directly by the audio amplifier.

When the AVC system receives an erroneous vehicle speed signal, the system does not change the current volume setting.

Watch

The IHU acts as the master system clock. The clock and dial are combined into one block located in IHU. Other vehicle modules that require a time function receive data from the IHU.

Any module connected to the communication bus, i.e. to any CAN bus (local area network of controllers) or MOST system.

The display can show the time in 12-hour format ("before noon" And "afternoon"), and can also be set to 24-hour format. Accordingly, midnight is designated as 12:00AM or 0:00. When power is connected, the default clock (if there are no other settings) will show 1:00PM or 13:00. Clocks default to either 12-hour or 24-hour format, depending on the delivery market.

The time setting is done via the IHU. This ensures that the time is always synchronized on all devices in the car. If any of the data buses are currently down or in "sleeping" mode, the system does not allow clock adjustment.

High quality Harman Kardon Logic 7 amplifier

Vehicles are equipped with one of the following two amplifiers:

• Harman Kardon
• Harman Kardon Logic 7

The amplifier is under the front RH (right) seat and connected to the audio system via the MOST bus.

C0491 speaker connector for Harman Kardon amplifier

contact no	Description	Input signal / output signal
1	(-) speaker rear LH (left) doors	-
2	(-) speaker rear RH (right) doors	-
3	Not used	-
4	Not used	-
5	(-) speaker front LH (left) doors	-
6	(-) speaker front RH (right) doors	-
7	(-) left subwoofer	-
8	(-) right subwoofer	-
9	(+) speaker rear LH (left) doors	Output signal
10	(+) speaker rear RH (right) doors	Output signal
11	Not used	-
12	Not used	-
13	(+) speaker front LH (left) doors	Output signal
14	(+) speaker front RH (right) doors	Output signal
15	(+) left subwoofer	Output signal
16	(+) right subwoofer	Output signal

C0491 speaker connector for Harman Kardon Logic 7 amplifier

contact no	Description	Input signal / output signal
1	(-) speaker rear LH (left) doors	-
2	(-) speaker rear RH (right) doors	-
3	(-) front LH (left) subwoofer	-
4	(-) front RH (right) subwoofer	-
5	(-) surround back left speaker	-
6	(-) surround back right speaker	-
7	(-) left subwoofer	-
8	(-) right subwoofer	-
9	(+) speaker rear LH (left) doors	Output signal
10	(+) speaker rear RH (right) doors	Output signal
11	(+) front LH (left) subwoofer	Output signal
12	(+) front RH (right) subwoofer	Output signal
13	(+) surround back left speaker	Output signal
14	(+) surround back right speaker	Output signal
15	(+) left subwoofer	Output signal
16	(+) right subwoofer	Output signal

C0492 speaker connector for Harman Kardon amplifier

contact no	Description	Input signal / output signal
1	Not used
2	Not used
3	Not used
4	Not used
5	Left channel of the 1st headphone module	Output signal
6	"Weight" right channel of the 1st headphone module	Output signal
7	"Weight" right channel of the 2nd headphone module	Output signal
8	Left channel of the 2nd headphone module	Output signal
9	Not used	-
10	Not used	-
11	Not used	-
12	Not used	-
13	Not used	-
14	Not used	-
15	"Weight" left channel of the 1st headphone module	-
16	"Weight" right channel of the 1st headphone module	-
17	"Weight" left channel of the 2nd headphone module	-
18	"Weight" right channel of the 2nd headphone module	-
19	Not used	-
20	Not used	-

C0493 speaker connector for Harman Kardon amplifier

contact no	Description	Input signal / output signal
1	Left channel of the 3rd headphone module	Output signal
2	"Weight" right channel of the 3rd headphone module	Output signal
3	Left channel of the 4th headphone module	Output signal
4	"Weight" right channel of the 4th headphone module	Output signal
5	Control signal of the 1st headphone module	Output signal
6	Control signal of the 2nd headphone module	Output signal
7	Control signal of the 3rd headphone module	Output signal
8	Control signal of the 4th headphone module	Output signal
9	Not used
10	Not used
11	"Weight" left channel of the 3rd headphone module	-
12	"Weight" right channel of the 3rd headphone module	-
13	"Weight" left channel of the 4th headphone module	-
14	"Weight" right channel of the 4th headphone module	-
15	"Weight" control signal of the 1st headphone module	-
16	"Weight" control signal of the 2nd headphone module	-
17	"Weight" control signal of the 3rd headphone module	-
18	"Weight" control signal of the 4th headphone module	-
19	Not used	-
20	Not used	-

C0492 speaker connector for Harman Kardon Logic 7 amplifier

contact no	Description	Input signal / output signal
1	(-) front LH (left) mid/tweeter	-
2	(-) front RH (right) mid/tweeter	-
3	(-) middle "filling" dynamics	-
4	Not used	-
5	Left channel of the 1st headphone module	Output signal
6	"Weight" right channel of the 1st headphone module	Output signal
7	Left channel of the 2nd headphone module	Output signal
8	"Weight" right channel of the 2nd headphone module	Output signal
9	Not used	-
10	Not used	-
11	(+) front LH (left) mid/tweeter	Output signal
12	(+) front RH (right) mid/tweeter	Output signal
13	(+) middle "filling" dynamics	Output signal
14	Not used	-
15	"Weight" left channel of the 1st headphone module	-
16	"Weight" right channel of the 1st headphone module	-
17	"Weight" left channel of the 2nd headphone module	-
18	"Weight" right channel of the 2nd headphone module	-
19	Not used	-
20	Not used	-

C0493 speaker connector for Harman Kardon Logic 7 amplifier

contact no	Description	Input signal / output signal
1	Left channel of the 3rd headphone module	Output signal
2	"Weight" right channel of the 3rd headphone module	Output signal
3	Left channel of the 4th headphone module	Output signal
4	"Weight" right channel of the 4th headphone module	Output signal
5	Control signal of the 1st headphone module	Output signal
6	Control signal of the 2nd headphone module	Output signal
7	Control signal of the 3rd headphone module	Output signal
8	Control signal of the 4th headphone module	Output signal
9	Not used	-
10	Not used	-
11	"Weight" left channel of the 3rd headphone module	-
12	"Weight" right channel of the 3rd headphone module	-
13	"Weight" left channel of the 4th headphone module	-
14	"Weight" right channel of the 4th headphone module	-
15	"Weight" control signal of the 1st headphone module	-
16	"Weight" control signal of the 2nd headphone module	-
17	"Weight" control signal of the 3rd headphone module	-
18	"Weight" control signal of the 4th headphone module	-
19	Not used	-
20	Not used	-

Steering wheel audio controls

Item name	Spare part number	Description
1		Distance control switches in adaptive cruise control mode
2		Audio Mode Select Switch
3		Volume control
4		Key to start a conversation
5		End key
6		Search switch in the audio system
7		Sound signal
8		Cruise control and set speed switch
9		Voice recognition switch
10		Cruise Control Switch

Steering wheel mounted switches allow remote control of the IHU. The audio controls are located on the right side of the steering wheel.

Controls are resistive multilink switches. The IHU provides a voltage reference to the switches, which provide the IHU with a varying voltage depending on which switch is pressed.

Using the controls, you can adjust the volume, switch records on the CD (CD) or radio stations, start or end a conversation (if the car is equipped with a telephone), as well as manage the voice recognition system.

Satellite digital radio (SDARS - US only)

SDARS systems operate in the microwave frequency range (2.3 GHz) and, thanks to the use of satellite data transmission, provide broadcasting with high sound quality (comparable to CD quality (CD)) over a very large area (usually continents). Network providers transmit various information from their enterprises to the satellite: data, speech, etc. through the antenna system. The satellite transmits this information both to ground relay stations and autonomous SDARS receivers, including car receivers. The receiver is able to switch from receiving the signal from the satellite to receiving the strongest signal coming from the relay station at any time.

Land Rover uses US provider Sirius Satellite Radio.

The SDARS Sirius system includes:

• Earth satellites
• Terrestrial repeaters
• Ground transmitting stations
• Radio reception systems

The Sirius SDARS system uses three satellites orbiting the Earth in inclined elliptical orbits. Each satellite is above the US territory for approximately 16 hours, i.e. at least one satellite is above the country at any time.

Signals from satellites are picked up by receivers or sent to repeaters, which allows you to receive transmissions even if the satellite is not in line of sight.

Road services messaging channel (TMC)

The TMC system only functions in Europe. Traffic information is received by the TMC receiver and used by the navigation system computer to calculate a route bypassing the traffic "traffic jams" and other obstacles. This information is transferred to RDS data carriers (radio data transmission system).