The receiver is part of the body computer.
REMOTE CONTROL AND RECEIVER
The remote control/receiver is interfaced with the BCN to activate the following functions:
activate the central locking and opening of the doors and, if applicable, windows, electric sunroof and the lighting up of the courtesy light.
switch on and off any alarm system.
The remote control system comprises:
transmitter: is built into the key handle, it is on radio frequency and sends a variable code to the receiver. It has two or three function control keys and an LED for checking the transmission of the code and the state of charge of the batteries.
receiver: radiofrequency built into the NBC with operating frequency of 433.92 MHz.
Memorises up to eight transmitters, and is characterised by a wire aerial which comes out of the BCN and is built into the dashboard wiring
The system is based on the transmission and receipt of a radio frequency signal with variable numerical code (Rolling Code).
Each transmission generates a variable code, managed by a mathematical algorithm.
The following figure shows the transmitter.
Picture of key/fob not reproduced
1 - Lock button
2 - Unlock button
3 - Boot button
The transmitter is the device which transmits the command code to the receiver; it is built into the key fob
The transmitter has a radio frequency stage at 433.92 MHz with range of 20 m.
It has 3 buttons and one LED: the buttons activate the control, while the LED visually checks that the transmitter is sending the code and indicates the discharged battery condition.
Pressing the buttons can be perceived by the user to allow tactile control of the command received. The position of the buttons is such as to prevent or minimise the risk of involuntary activations (e.g. at the time of key-on).
The remote control has 3 buttons called lock, unlock, boot.
LOCK: when the lock button is pressed, the doors are locked. When the button is held down for more than 4 s, the windows are closed and the sunroof is closed (SUPER LOCKING). When the button is released, the movements are interrupted; to resume movement press again for 4 seconds.
UNLOCK: when the unlock button is pressed, the doors are unlocked and the courtesy light is switched on. If the button is held down for more than 4 s, the windows and sunroof are opened (SUPER OPENING). When the button is released, the movements are interrupted; to resume movement press again for 4 seconds.
BOOT: When the button is pressed, the boot / tailgate is released, visible by it lifting slightly.
The receiver is located in the BCN and has a wire aerial which emerges from the body computer.
Receiver module with operating frequency 433.92 MHz, and has the following functions:
it receives and decodes the signals coming from the transmitter
it manages the memorisation of a maximum of 8 transmitters
it generates the command for opening and closing the doors (actuating as appropriate the exit from blinker command, if required).
it activates and deactivates the alarm system.
it generates the command to light up the timed courtesy light.
The remote control and receiver system has two operating states:
Switch on command
With the switch-on command, the receiver sends a signal to the BCN which:
activates the door locking
issues the instruction to change from rest to surveillance to the larm system, in the case of prepared BC.
The command to switch on is made by pressing the button on the transmitter: it is indicated by the direction indicators coming on for 2.5 s (the indication is enabled/disabled by EEPROM).
Switching on is always inhibited (except in diagnosis) if the key-on +15 signal is present.
While the button is being pressed, the flashing frequency of the transmitter LED is 3 Hz.
The transmitter makes a complete transmission of the variable code in response to continued pressure on the button lasting at least 50 ms.
If the button is held pressed continuously, the transmitter interrupts the transmission after 20 s; to transmit further, release and press again the button on the transmitter.
If the receiver recognizes a continuous transmission (code received always the same), after the initial switching of state, it excludes the possibility of a continuous switching of the control.
The receiver acquires the variable code, compares it with the codes memorised during programming and recognises it as one of those.
After recognising the code, the receiver controls the locking of the doors and the change from rest to surveillance of the alarm in the case of prepared BC.
Last edited by Davffc; 25-07-15 at 18:09.