Support > Frequently Asked Questions

Car Security Glossary

Upon installing a vehicle security system, the installer is faced with a question - "where to start ?"

CHASSIS CONNECTION

Regardless of brand regardless of model the first wire to connect should always be the chassis wire. It provides reference for every action taken by the system. Chassis connections must always be an independent connection, the wire terminated by a eye terminal which is the screwed onto the metal chassis of the vehicle.

POWER CONNECTION

The wire responsible for supplying the system with energy is the power wire. A vehicle security system should never have power interrupted for any reason during operation. Connected the power wire to the huge source of +12VDC , the back of the vehicle's fuse box ensures the system will loose power only if the whole vehicle looses power. The largest (usually red) wire is the best candidate.

With these two wires connected you can now operate most remote security systems.

INPUT CONNECTIONS

Vehicle security systems need to know when the user is driving the vehicle. This is to ensure the automatic arming feature is not engaged. For this reason we need to connect the ignition sense wire to an output from the vehicle ignition switch which supplies +12VDC when the ignition key is in the ON position.

Most systems allow for a negative door input for either theft alert or for programming features. Most modern vehicles provide a common door signal

CENTRAL DOOR LOCKING (CDL)

Central Door locking, an electronic means by which vehicle doors are locked and unlocked.Electronic actuators convert current into movement.

BODY CONTROL MODULE (BCM)

Body Control Module is the module that controls the vehicle's central locking, power windows, indicators and alike. Usually mounted behind

DIODE

Semiconductor component which allows current to pass in one direction only.


1N4004 - 1 amp 400VDC

These diodes should be used to split low current signals only. We have seen 1n4004's operate at (3amps) well above the specified current rating - but it is considered unsafe.


1N5404 - 3 amp 400VDC

These diodes may be used for both low current signal and high current use (indicator signal splits)

FLOATING

A floating wire is one that is not connected to +12V or chassis. Examples of floating outputs are the central locking wires of all Dynamco alarms and immobilisers.

A floating output place no load onto the input circuitry of any given devise.

Floating connection voltages are undetermined.

To fix floating connections, a 1K resistor is a commonly used resistor to connect between the connection and +12V or ground.

Floating explained

"NEG OUT WHEN ARMED" SIGNAL

Many alarms and immobilisers provide a negative output when armed signal. This signal is designed to ground the following :

MILLIVOLT SENSING

Millivolt or Voltage drop sensing uses amplifiers to magnify the voltage drop across a car battery when a device is switched on. Dynamco millivolt sensing typically triggers if a voltage drop of more than 10mV in 10mS. This is the sharp short drop experienced when a boot or courtesy light is switched on.

The voltage drop does not occur when the device is switched off, nor when the device is left on.

Millivolt diagram - Voltage Vs Time

CHANGING OPTIONS

All Dynamco alarms and immobiliser allow for some option changes. Each option can be changed via the vehicle's ignition switch. To alter an option follow this procedure:

NB P455 upgrade will automatically change when ignition is left on after ignition flash (DO NOT PRESS FACTORY REMOTE).
The system will then flash either once or three times, informing you the new state of the option you have changed, refer to specific installation instructions for each system (or else this summary of all units).

ROLLING CODE

Rolling Code or Code Hopping defines the type of code transmission that alters the message each time the remote is pressed.

The nature of RF remote controls means any code can be received by anyone in the transmission area. If a thief records your remote transmission, they can re-play the transmission once you leave your car. Your vehicle is now ready to be stolen.

Rolling code never uses the same code twice. Codes re-played by the would-be thief will be ignored.

DIAGNOSTICS

A report is given after an alarm with the diagnostics feature is triggered. The indicators and status LED flash a given number of times. Each number defines which zone of the vehicle was responsible for the trigger.

If the report is missed, the P755, 775 & 785 can replay the last three diagnostics by pressing both buttons on the remote control for 3 seconds. These reports are given in reverse order (most recent first, then prior, then prior to that). The reports can be repeated as many times as needed. However, the report is cleared the very next time the ignition switch is turned on.

The P455 & P485 will also report the last three triggers when the siren is switched off and back on. Reports will also occur when the power is removed and re-applied.

Number of flashes

P755, P775, P785

P455

P500, 504PB, 302PB, 502RF, A502RF, A502CH

1

Bonnet

Bonnet

Bonnet

2

Auxilary

Millivolt

Millvolt

3

Doors

Doors

Doors

4

Glass Breakage

Glass Breakage

Glass Breakage

5

N/A

N/A

Ignition (hotwire)

6

N/A

N/A

Auxilary