ANTI-THEFT DEVICE

Description 5580E

FIAT CODE SYSTEM

The vehicles are equipped with an electronic system known as the FIAT CODE to produce the engine immobilizer function.

The FIAT CODE system only allows the engine to be started by means of the Engine Management Node (NCM) after a secret code, memorized previously in the NCM, is received.

The second generation Code system is incorporated in the Body Computer Node (NBC).

The FIAT CODE system comprises the following components (in addition to the Body Computer which acts as a control unit):

- CAN line for dialogue between the NBC and the NCM

- Engine Management Node (NCM).

- electronic key containing a transponder with a secret code;

- an aerial that reads the code contained in the key transponder;

1 - Body Computer (NBC)

2 - Engine Management node (NCM)

3 - Aerial

4 - Key

Operation

The FIAT CODE allows the start of the engine management by the NCM by means of a coded dialogue between the NBC and NCM during the stage that precedes starting.

After the key is turned to the ON position, the NCM sends a code request to the NBC which only responds after having recognized (via the aerial) a known electronic key in the ignition switch.

If the secret code in the answer is valid, the NCM continues with the regular engine management activities, allowing the engine to be started up.

The NCM can only memorize the secret code through a special procedure.

Interaction between the fiat code and the key

Each key contains a transponder with a SECRET CODE.

As soon as the key is turned ON, the transponder converses with the NBC which, having recognized it as one of the enabled ones, continues with the NCM recognition strategy.

If the identification code is not recognized, the procedure is aborted and the engine cannot be started.

The recognition of the SECRET CODE takes place by means of a challenge-response algorithm with the exchange of an encrypted code. The code recognition time is a maximum of 160 ms per attempt.

The FIAT CODE attempts the transponder acquisition for up to 1.3 seconds.

Communication between the engine control node and the fiat code

The dialogue between the FIAT CODE (NBC) and the NCM contol units takes place via the CAN.

Every exchange of information between the FIAT CODE and the NCM is guided by the NCM (the NBC never interrogates the NCM but only responds after a request).

After KEY-ON, the flow of code exchange operations between the NBC and the NCM depends on the status (blank or memorised) of the NCM.

If the NCM is pristine, the procedure involves sending the secret code request to the NBC: in this way the NCM learns the secret code and stores it in its memory. This procedure is known as CODE RECORDING.

If the NCM has already been programmed, the procedure involves checking that the codes stored in the engine management control unit memory and the one memorized in the NBC correspond:

This procedure is known as CODE VERIFY.

1 - Key on

2 - NCM initialisation

10- FLGOPT = 1 ?

3 - NCM status memorized OK, pristine NOT OK

A - CODE VERIFY

7 - Is the secret code valid?

8 - the operation of the engine is allowed

B - CODE RECORDING

4 - Memorisation successfully completed?

5 - the operation of the engine is allowed

6 - the operation of the engine is not allowed

Code recording

The CODE RECORDING procedure is the memorizing of the secret codes in the engine control unit.

Only after the NBC has memorized the identification codes and the secret codes, is the NBC ready to satisfy the request to transmit a code to a pristine NCM.

After a key on, the engine management unit initialises its software and requests the secret codes if it is blank.

If the NBC is not pristine, it responds by sending the secret codes, but only after having recognized an authorized key. If the key is not authorized (unrecognized) or there is no key, the NBC does not respond.

If the NBC is pristine and there is no transponder in the key and a request is sent for secret codes from the NCM, the NBC does not respond.

Code verify

This is the standard procedure that is repeated during the life of the vehicle each time the user insesrts the key in the ignition and turns it ON. this procedure enables the starting of the engine if the key inserted is enabled.

If it is not completed, the code verify procedure continues even when the user turns the key to the starting position.

After the key is in the ON position, the NBC recognizes whether the transponder in the key is one of those that is enabled.

At the same time, with the ignition in the ON or starting position, the NCM initializes its software to check whether the secret codes have been memorized. If the answer is yes, it sends a request to the NBC.

If the result of the transponder recognition is negative (incorrect transponder, no transponder in the key, etc.), the NBC will sent a negative authorization response to the engine management control unit.

In response to this request, it only sends the secret encrypted codes to the engine management control unit if the transponder is recognized as enabled.

If the NBC is pristine and the NCM sends a request for secret codes, the NBC, after having recognized the presence of a recognized transponder, responds by sending a positive authorization reply.

Communication via the can

Communication via the Body Computer and the NCM takes place via the following two CAN messages:

- immo code request (sent by the NCM and received by the NBC)

- immo code response (sent by the NBC and received by the NCM)

Protection codes

The protection codes used by the NBC and NCM are listed below

- UNIVERSAL CODE: this is the code that an unprogrammed NBC sends to the NCM when it detects the presence of a transponder in the key. The "vehicle protection" warning light comes on at a frequency of 1.6 Hz and 50% duty cycle. The warning light flashing signals that the system is properly connected and working, but the vehicle is not protected by a code.

- SECRET CODES: these are the codes in the transponder. They are is stored in the transponders contained in the keys when the transponders are programmed and in the NBC when the keys are programmed at the end of line.

- ELECTRONIC CODE (PIN): this is printed on the CODE CARD, which is given to the vehicle owner. It takes the form of a 5-figure decimal code (0 is not permitted). It is used to access the NBC memory in protected mode in order to reprogram or program new remote control keys and/or perform specific diagnostic functions.

- IDENTIFIER: This is resident in the transponder and different for each transponder. It is stored in the NBC during the programming procedure. The NBC manages a table of enabled identifiers and another table of disabled identifiers.

Body computer

The FIAT CODE is an internal function of the Body Computer Node (NBC).

The main FIAT CODE functions are:

- recognizing the introduction and rotation of a key in the ignition (ON);

- conversing with the key transponder by means of the immobilizer aerial;

- to store up to 8 identification codes;

- memorizing the secret codes;

- to manage a list of 4 permanently disabled identifiers;

- managing the CAN line towards the engine management control unit;

- managing the activation of the warning light on the panel via communication with the instrument panel;

- carrying out the autodiagnosis for the CODE system functions.

FIAT CODE supplied as spares:

If the FIAT CODE function is replaced, the entire Body Computer must be replaced. To replace the Body Computer, a request must be made to the Parts Dept. providing the vehicle chassis number as described below.

Aerial

The aerial assembly comprises an toroid type aerial with a connector built into the aerial body.

The wiring connected to the NBC is incorporated in the dashboard cable loom

The aerial is supplied by the NBC to energize the key transponder.

Since the aerial needs to be as close as possible to the transponder (on account of electro-magnetic immunity, the limited range of the transponder and small dimensions) it is fastened axially to the ignition switch.

- 1 CODE aerial

- 2 Ignition switch

Ignition key

The mechanical key contains a cipher transponder in the grip.

The moment the key is inserted in the ignition and turned to the ON position, the transponder is energized by the aerial and responds by emitting the rolling, encrypted secret code.

If the code is recognized as valid, the NBC sends the engine control unit, on request, a coded signal allowing the engine to be started.

Up to 8 keys can be programmed in the NBC

Transponder in the key

The transponder in the key has the following stored in its memory:

- SECRET CODE;

- IDENTIFIER which is different for each transponder produced;

- PROGRAMMING DATA for the secret code.

The identification code differs from transponder to transponder to guarantee that no two transponders have the same identification code even if there is a request for a duplicate in the Network.

Reprogramming keys

Reprogramming the keys involves storing the keys enabled upon vehicle start-up in the NBC.

Both the new keys to be programmed and those already programmed are inserted into the ignition to be recognized by the NBC: this memorizes the keys presented during the procedure in the enabled identification codes tables and transfers those no longer presented to the disabled identification codes table.

Disabled keys table

If an enabled key is no longer available (mislaid, stolen or no longer working), the subsequent key programming procedure (in which the key is no longer presented) disables its operation.

The NBC manages a table in the EEPROM that can contain data on 4 disabled keys: the identifiers of enabled keys not presented during the reprogramming procedure are transferred to this table.

If the disabled keys table is full, any new key will replace the first entered in the table.

This table also allows the traceability of keys used on the vehicle.

Key reprogramming procedure

The key reprogramming procedure is performed/guided by the EXAMINER Diagnostic Equipment: this procedure is activated by means of access protected by the vehicle PIN.

Continue by following the instructions on the diagnostic instrument/EXAMINER.

It is possible to program up to 8 enabled keys.

Deleting a lost key from the memory

At any time it is possible to delete a lost key from the memory using the EXAMINER Diagnostic Equpment. The identifier of this key is transferred to the disabled identifier table and will no longer be recognised.

Code card

This card shows:

- The emergency code (electronic code) that allows the Service Network to program electronic keys (TEGs) and remote controls using an EXAMINER.

- The emergency key mechanical code identifies the mechanical profile of the key and must be specified on the order to receive the key already cut.

1 - Electronic code

2 - Mechanical code

Operation

The electronic emergency code is also used for system diagnosis and for other operations using Examiner or other diagnostic instruments. Many of these operations (e.g. key programming) can be carried out only once this code has been entered.

Before any operation, it is therefore necessary to ask the Customer for their Code Card.

The Code Card must not be left in the vehicle in case it is stolen.

Vehicle protection warning light

The vehicle protection warning light is located in the instrument panel and is controlled by a message from the NBC on the B-CAN.

Operating mode and vehicle protection warning light flashing time

The NBC controls the switching on of the vehicle protection warning light in the panel, via the CAN, flashing to signal programming errors for the Body Computer or the NCM.

Fault diagnosis

The ALFA CODE function allows self-diagnosis to be carried out for system components.

The NBC is capable of identifying and memorizing the presence of the following malfunctions in its EEPROM:

Transponder:

- defective or missing transponder or secret code incorrect

- deleted/disabled

- unknown/not memorized

Transponder aerial:

- electrical connection defective (circuit open, short circuit to earth or to battery)

ALARM SYSTEM

The alarm system performs:

- perimeter surveillance,

- volumetric surveillance,

- anti-tilt surveillance,

- surveillance of supply lead cutting.

System operation is co-ordinated by the Body Computer, wihch sends/receives commands from external modules via the serial line.

The system is turned on/off by means of a remote control interfaced witha receiver in the NBC, the remote control unit and the receiver are radio controlled.

The doors are locked upon insertion.

To exclude the alarm completely (for example, in the case of a long period of inactivity for the vehicle) the vehicle should be closed by turning the metal insert in the key in the lock without using the remote control.

The volumetric and anti-tilt protection can be excluded by operating a button in the front courtesy light.

Every break in attempt is signalled by the code warning light in the instrument panel coming on together with a message shown in the display.

The control unit is equipped with a self-diagnostic function which detects and memorises faults and problems in the control unit and system components; in addition, it checks the condition of the connecting cables and saves the number of activations and times the alarm has been operated.

The control unit operating logic can be modified in order to satisfy the legal requirements which govern the use of alarm systems in the various markets.

DIRECT INPUTS:

- Negative signal from NA switch signalling front driver''s door open

- Negative signal from NA switch signalling front passenger door open

- Negative signal from NA switch signalling left rear door open

- Negative signal from NA switch signalling right rear door open

- Negative signal from NA switch signalling boot open

- Negative signal from NC switch signalling bonnet open

- Ignition-operated power supply (+15)

- Serial line with volumetric/antitilt sensor control unit

- DIRECT OUTPUTS

- Serial line with alarm control unit and volumetric/antitilt sensor control unit

- Direction indicators activation

- A-bus serial line

Structure

The alarm system consists of the following modules:

- Body Computer: manages system operation and controls external modules.

- Sensors on the doors, boot and bonnet: detect attempts to open the doors, boot and bonnet.

- Remote control system (sending unit + receiver included in the NBC)

- Siren: emits signal beeps and an acoustic alarm.

- Ultrasound sensors: detect movements inside the passenger compartment.

- Anti-tilt sensor: detects a change in vehicle tilt following a lift.

- A-bus serial line: connects all relevant modules to the alarm system.

1 - NBC

2 - Switches on doors

3 - Siren

4 - Ultrasound/antitilt sensors

5 - Remote control

Operation

There are eight different possible states for the alarm system:

- DEACTIVATED;

- REST;

- ON;

- SURVEILLANCE;

- ALARM;

- OFF;

- PROGRAMMING;

- FAULT DIAGNOSIS;

Each of these statuses is described in the following paragraphs.

Deactivated

Deactivated status is the BC''s status whenever the FIAT CODE detects an enabled key.

This operation effectively turns off the alarm.

When the alarm system is deactivated it does not respond to the commands from the receiver (key on).

It changes from deactivated to rest status when the key is removed.

Rest

Rest status is the basic alarm system status.

It is possible to change from rest status to the following statuses:

- fault diagnosis: when a diagnostic session is activated by means of a diagnostic instrument connected to the BC.

- surveillance: when the vehicle is protected by issing an on command and passing through the on stage.

- deactivated: when the FIAT CODE recognizes an enabled key.

In rest condition, the BC continues to acquire the +15 status to stop the system changing to surveillance mode and above all to prevent alarm activation

This information distinguishes two fundamental rest modes: vehicle operating (+15 present) or left (+15 absent), which is a prelude to surveillance mode.

During rest status, it is possible to cut out volumetric and antitilt protection manually within one minute of KEY OFF.

On

The on command changes the alarm from rest to surveillance mode

This operation is always inhibited in the presence of a +15 signal.

The on command is issued by pressing the sending unit key. It is indicated by the turn signals coming on for 2.5 s and the emission of a synchronous beep.

When the command is received, the BC activates the alarm activation procedure as described within 100 ms:

SIGNALLING OF SWITCHING ON IN PROGRESS:

- Blinkers activated with fixed light for 1 s.

- LED in central locking button on constantly for 1 sec.

- BEEP command sent to siren.

SYSTEM DIAGNOSIS/VERIFICATION:

The control unit diagnoses the following components:

- Volumetric/tilt sensor modules;

- siren;

It verifies sensor status via appropriate commands:

- after max. 3 seconds, the siren;

- after max. 3 seconds, the siren;

- after max. 4 seconds, the volumetric sensor module;

- after max. 4 seconds the tilt module (if present).

If the responses to the verification commands are not received within the requiered times, the module is declared non-operational.

Plausibility of door (2 or 4), bonnet and boot switch statuses is also checked (perimeter protection): If one of the entrances if found not to be closed, this entrance is excluded from surveillance.

DIAGNOSTIC INFORMATION DISPLAY:

The signalling of problems when switching on is carried out by the warning light in the control panel which is only supplied at the next Key On.

Automatic activation

The automatic activation function can only be activated in certain markets.

Automatic activation allows the alarm system to switch from rest to surveillance mode in automatic, timed manner.

Two self-activation modes are provided.

FROM KEY-OFF:

- KEY OFF is detected;

- The self-activation counter begins counting;

- If a closed/open transition is detected at any of the driver''s doors or the bonnet or the boot then the counter begins from zero;.

- The counter reaches the "SELF-ACTIVATION TIME" value.

- The BC checks whether an enabled key is inserted;

- If an enabled key is inserted, self-activation takes place;

- If no enabled key is present, self-activation does not take place.

PASSIVE mode (last door):

- KEY OFF is detected;

- The self-activation counter begins counting;

- If a closed/open transition is detected at the driver''s door, on any of the doors or the bonnet or the boot then the counter begins from zero;.

- if the counter reaches 2 minutes wihtout any open to closed transition being recorded, self-activation is cancelled;

- the counter reaches the "SELF-ACTIVATION TIME" value;

- The BC checks whether an enabled key is inserted;

- if an enabled key is inserted, self-activation takes place;

- if no enabled TEG is present, self-activation does not take place;

Self-activation modes are enabled according to the operating mode (see country map table "PASSIVE SELF-ACTIVATION ENABLEMENT" and "KEY-OFF SELF-ACTIVATION ENABLEMENT").

Surveillance from self-activation is complete for all entrances. The operating modes allow:

- activation/deactivation of volumetric surveillance.

- activation/deactivation of the tilt module.

The central locking is not activated during the self-activation stage.

Warning lights/acoustic signals are enabled by the operating mode.

The definition of the driver''s side door for different specifications (RHD and LHD) is specified during the manufacturer''s end of line programming.

Reactivation

The reactivation operation allows the sytem to move automatically from the REST stage to the SURVEILLANCE stage when, after an authorized deactivation, door/boot/bonnet opening or other consistent actions are not found to have occurred.

The procedure for reactivation is as follows:

- The alarm system is switched off.

- The reactivation counter begins counting.

- If a closed/open transition is detected at any of the doors or the bonnet or the boot then reactivation is cancelled;.

- The counter reaches the "SELF-ACTIVATION TIME" value.

- The alarm is switched on taking into account any system exclusions (volumetric protection, siren,...) made at the last switching on.

Surveillance

During surveillance status, the BC performs the followign operations:

- +15 SIGNAL CHECK

The BC downloads information on the presence of a +15 signal: if it detects the presence of the +15 signal for longer than 100 ms without a previous deactivation command, the BC interprets this manoeuvre as a theft attempt and controls the changeover to alarm status.

- EXCLUSION OF EXTERNAL MODULES DUE TO LOW BATTERY VOLTAGE

If the battery voltage is below 8.5 V for longer than 30 mins, the BC deactivates external modules (volumetric sensors, tilt sensor) in order to safeguard the life of the battery and to be able to start up the engine later on.

- PERIMETER SURVEILLANCE

The BC monitors the status of the six inputs from the four doors, bonnet and boot: If one of these changes status for longer than 500 ms, the BC changes to alarm status.

- PROTECTION AGAINST FALSE ALARMS DUE TO BC RESET

During the surveillance stage, external interference or a theft attempt could cause the BC to reset and re-initialise its functions.

In this case, the BC check whether the alarm was on before the reset so it can re-activate the external modules, except from those excluded at the last activation.

- ALARM ACTIVATION

During the surveillance stage, the alarm may be activated by the perimeter protection and also by external modules or the siren (due to the wires being cut).

When one of the alarm activation signals is received, the BC immediately changes to alarm status and triggers the cycle specified for the type of alarm received.

Alarm

If one of the sensors involved in the surveillance identifies an irregular situation (attempted or actual intrusion, interference and/or theft of the vehicle), the alarm sytem moves to ALARM status.

Alarm status is characterised by the activation of optical/acoustic signals consisting of activation of the siren and indicators.

SIGNALS

The signalling consists of a succession of alarm cycles.

Operating mode parameters are defined in the operating mode table.

The type, numbmer and duration of alarm cycles for each mode are managed by the BC: the siren may only be turned on (sound emission starts) and off (sound emission ceases).

For example, if the operating mode requires the emission of 3 alarm cycles lasting 26s at 6s intervals, the BC will behave as follows:

- Blinker activation and control of siren activation with associated sound configuration parameters.

- After 26s of blinker deactivation, the siren is deactivated.

- 6s wait.

- Repetition of previous points until the cycles are exhausted.

STORING THE ALARM CAUSE

For diagnostic purposes, a record of the alarm causes recognised by the BC is kept.

The NBC memorizes the last 10 alarm causes, associating the cause and alarm system state at the time the system wash switched on with each of the causes.

The following alarm causes can be memorised:

- driver''s front door

- front passenger door

- left rear door

- right rear door

- ultrasound sensor

- anti-tilt sensor

- cutting of siren cables

- boot

- bonnet

- +15

- cutting of +30 cable

- siren intrusion with incorrect siren deactivation command

- intrusion on external modules wiht ultrasound/antitilt deactivation command

- incorrect heart-beat

For each alarm cause, the system status is memorised, described by:

- left front door open

- right front door open

- left rear door open

- right rear door open

- bonnet open

- boot open

- system activated by self-activation

- system activated by remote control

- ultrasound sensor defective

- anti-tilt sensor defective

- siren defective

- serial line not operational

The system changes from alarm status to the following statuses:

- rest: via a deactivation command or via detection of key on by the FIAT CODE of an enabled key.

- surveillance: when the alarm cycles set off are ended.

Deactivation

Deactivation may occur in surveillance mode or in alarm mode.

This is carried out by pressing the key on the sending unit, which commands the BC to deactivate the alarm system according to the following procedure: deactivation is indicated by two flashes of the 1 Hz blinkers and two synchronous beeps (indication is enabled/non enabled according to the operating mode).

This signal is activated within 100 ms of receiving the deactivation command:

- the siren is deactivated.

- external modules are deactivated.

- the NBC interrupts the perimeter protection and, if present, al the counter-measures activated.

The command is activated even with the +15 signal present.

After deactivating and at the first key on, the control unit runs the signals for sending unit batteries flat, alarms from volumetric, tilt and perimeter sensors, +15 and +30.

End of line programming

It is possible to program the configuration of the alarm system installed on the vehicle at the end of line by defining the presence/absence of the following modules:

- siren;

- ultrasound module;

- tilt module.

This information can be read, but not modified, by the diagnostic equipment which will adapt its diagnostic procedures depending on the configuration present.

The configuration is transferred to the Body Computer by means of the vehicle Customisation procedure (PROXI).

Programming operating modes

Programming status allows the BC to store active operating mode in its EEPROM.

It allows the alarm system to be configured so that it acts in accordance with legal requirements expressed in the operating mode table.

During programming, the system changes to rest status.

Operating modes

A list of the different operating modes is given below:

MODE 1 DEFAULT MODE (EEC)

MODE 2 (Great Britain)

MODE 3 (Belgium)

MODE 4 (Holland)

MODE 5 (World)

MODE 6 (Temporary market)

Operating mode table

The market may be changed from 1,2,3,4,5 using a diagnostic tester or manual procedure.

It is not possible to enable/disable the market by entering 0.

Diagnosing external modules

The BC diagnoses the operation of the serial line for connection to the siren and external modules, checking for short circuits to earth, to the battery and for the presence of open circuits.

A diagnostic check is carried out on the serial line when communication is activated, typically upon activation of the alarm system.

The external modules are diagnosed when the system is activated by diagnostic commands from which the following information is obtained.

No diagnostic checks are required for the perimeter protection switches.

The diagnostic information obtained at the time of activation is stored in the EEPROM to ensure the system can be serviced.

To carry out fault diagnosis, use the diagnostic equipment provided.

Active diagnosis

During a diagnostic session, the BC may be required to carry out a diagnostic check on the external modules: the BC then sends the appropriate command and communicates the outcome to the diagnostic instrument.

If the BC cannot communicate with the module during this operation, the response to the diagnostic instrument will be:

- serial line interference

- module not responding.

Similarly, a diagnostic check may be requested on the serial line, with the following possible outcomes. OK, short circuit to earth, short circuit to battery.

It is also possible to read the alarm cause table stored in the BC.

Recovery

If an external module (ultrasound, tilt) is recognized as not functioning, it is excluded for the entire surveillance cycle.

The next time the system is switched on, the diagnostic check is carried out again on the modules which should be reactivated if they are recognized as working.

Components

Anti-theft device siren

The following figure shows the antitheft siren.

The main specifications of the siren are:

- sealed casing;

- green batteries for self-powering once the cables have been cut;

- battery recharging from control;

- programmable acoustic emission type;

- serial communication with the body computer and other alarm system components;

- self-diagnostics.

The siren (Stand –alone) is connected to the rest of the system with:

- a dedicated serial line between the NBC and siren;

- power supply for the siren/internal battery recharging.

The siren can respond to diagnostic messages sent by the NBC (internal self-diagnosis).

The siren is located in the engine compartment, in the housing under the windscreen.

SIREN PIN OUT

1 - Siren power supply

2 - Serial line

3 - Earth

4 - N.C.

Volumetric / tilt sensors

The volumetric and anti-tilt sensors are located inside the courtesy light.

The volumetric sensors consist of a receiver and an ultrasound receiver fitted in a module connected to the antitheft control unit.

The tilt sensor detects angular changes compared to the vehicle''s longitudinal axis and transverse axis.

Both sensors may be deactivated (both together and not separately) by means of the appropriate button.

1 - Sensor deactivation button

2 - Sensor deactivation LED

3 - Ultrasound volumetric sensors

4 - Tilt sensor (inside courtesy light)

Receiver

The remote control/receiver system interfaces with the NBC to activate the following functions:

- activate the central opening and closing of the doors and, in some cases, the windows,

- turn the alarm system on and off.

The remote control system consists of:

- transmitter: incorporated in the key: radiofrequency, sends a rolling code to the receiver. It has three function control keys and a LED to verify code transmission and battery charge status.

- receiver: radio-controlled, built into the NBC with operating frequency of 433.92 Mhz.

The receiver is located in the NBC and equipped with a wire aerial that emerges from the body computer.

The receiver module has the following functions:

- to receive and decode signals from the sending unit;

- store up to 8 transmitters;

- generate a door opening and closure command (by exiting blinker control, if required);

- turn the alarm system on and off;

The remote control and receiver system has two operating modes:

- on;

- off.

ON CONTROL

At the on control, the receiver sends a signal to the NBC, which:

- implements door locking

- controls a change in alarm system status from rest to surveillance if the BC is designed to do this.

The on command is issued by pressing a key on the sending unit: it is indicated by the turn signals coming on for 2.5 s (lthe signal is enabled/disabled via the EEPROM).

Activation is permanently inhibited (except during diagnosis) with the +15 key-on signal present.

When the key is pressed, the sending unit LED flashing frequency is 3 Hz.

The sending unit transmits the full rolling code in response to continuous pressure on the key lasting at least 50 ms.

If the key is held down continuously, the sending unit interrupts transmission after 20s. To continue transmitting, release the button on the sending unit and press again.

If the receiver detects a continuous transmission (code received always the same), after the first status switch, it excludes the possibility of continuous command switching.

1 - Mechanical key

2 - Door locking/unlocking buttons, alarm activation/deactivation

3 - LED for transmission of code and battery charge status

ON

The receiver acquires the rolling code, compares it with codes stored during the programming stage and identifies it from among them.

Once the code has been recognised, the receiver locks the doors and changes the alarm from rest to surveillance mode if the BC is designed to do this.

If the BC contains an alarm system, if the vehicle has been locked beforehand using a mechanical key, the BC must implement the door lock/alarm activation as indicated below when the sending unit button is activated:

- doors locked with key and alarm off (self-activation time not yet elapsed): no door lock operation and alarm activation;

- doors locked with key and alarm on (self-activation time already elapsed): operation of door lock (opening) and alarm deactivation;

- doors released and alarm off (self-activation time not yet elapsed): operation of door lock (locking) and alarm activation;

- doors released and alarm on (self-activation time already elapsed): no door lock operation and alarm deactivation;

DEACTIVATION

Once the receiver has received an off command from the sending unit, it sends a message to the NBC which:

- controls door release.

- controls a change in alarm system status from surveillance to rest if the BC is designed to do this.

The system is turned off by pressing the key on the sending unit: the signal is issued by two flashes of the blinkers at 1 Hz, d.c. 50% (function enabled/disabled via the EEPROM).

Deactivation is enabled even with the +15 signal present.

The receiver controls release according to the rules described in the activation paragraph (only if lock status is active).

Alarm system deactivation is also controlled.