Emergency alarm function - GF82.25-P-2011FL

MODEL 212 with CODE 934 (Taxi emergency alarm unit) with CODE 965 (Electrical preinstallation, rental vehicles) 

Function requirements, general 

• Circuit 30 ON

Emergency alarm, general 

The emergency alarm function is a protective device for the taxi driver. The emergency alarm can be triggered by the taxi driver if he/she feels threatened by someone. At the same time, a radio help call can also be triggered.

The emergency alarm function consists of the following subfunctions:

• Function sequence for emergency alarm 
• Function sequence for radio help call 
• Function sequence for display of fault messages 

Function sequence for emergency alarm 

The emergency alarm can be activated via the taxi emergency alarm system radio remote triggering transmitter (A8/4) (full alarm) or via the taxi emergency alarm system "Trigger" button (S62/6) concealed in the driver footwell. An active emergency alarm is ended by pressing the taxi emergency alarm system "Delete" button (S62/5).

Depending on the programming, a radio help call can also be triggered.

The following variants of the emergency alarm can be output:

• Function sequence for silent alarm 
• Function sequence for full alarm 

Function sequence for silent alarm 

The silent alarm is intended to prevent the threatening person from noticing the alarm triggering. The silent alarm is requested by pressing the "Trigger" button once. The special-purpose vehicle multifunction control unit (N26/9) reads in the status of the "Trigger" button directly, evaluates this and actuates the roof sign lamp (E14/4) (with code (342) Roof sign connection for taxi) with a frequency of f = 2.5 Hz.

Function sequence for full alarm 

In the event of a full alarm, the following functions are also triggered in addition to the output of the silent alarm:

• Exterior lights (flashing)
• Interior illumination (static)
• Acoustic alarm

The full alarm is requested by pressing the "Trigger" button or the radio remote triggering transmitter twice within t = 3 s. The multifunction control unit directly reads in the status of the "Trigger" button.

Vehicles without code (889) Keyless-Go:

Upon pressing the radio remote triggering transmitter, this sends the request to trigger the full alarm via the rear window antenna (A2/32), FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier (A2/18), rear SAM control unit with fuse and relay module (N10/2), interior CAN (CAN B), electronic ignition lock control unit (N73) and interior CAN to the multifunction control unit.

Vehicles with code (889) Keyless Go:

Upon pressing the radio remote triggering transmitter, this sends the request to trigger the full alarm via the rear window antenna, FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier, KEYLESS-GO control unit (N69/5), interior CAN, electronic ignition lock control unit (N73) and interior CAN to the multifunction control unit.

The multifunction control unit evaluates the request in both cases and sends corresponding information via interior CAN to the front SAM control unit, which then evaluates this and initiates the output of the alarm.

For security reasons, the request for the full alarm via the radio remote triggering transmitter is automatically repeated after t = 30 s. A reset takes place by pressing the "Delete" button once. The radio help call is also reset in the vehicle using the "Delete" button, but depending on the radio system it may be necessary to deactivate the radio help call in the radio system.

Exterior lights:

During output of the full alarm, the following functions are actuated to flash:

• Hazard warning flasher actuation
• Standing lights actuation
• Low beam and high beam actuation
• Front fog light illumination (without code (615) Bi-xenon headlamp unit with integrated curve illumination and without code (616) Bi-xenon headlamp unit with integrated asymmetrical curve illumination and without code (621) Intelligent Light System (left-hand traffic) and without code (622) Intelligent Light System (right-hand traffic))

Detailed information on the actuation of individual components of the exterior lights can be found in the separate function description "Exterior lights, function".

Interior illumination:

The interior illumination is switched on in the event of a full alarm.

Detailed information on the actuation of individual components of the interior illumination can be found in the separate function description "Interior illumination, function".

Acoustic alarm:

An acoustic alarm is output in the event of a full alarm. The front SAM control unit actuates the left horn (H2) and the right horn (H2/1) via the horns relay (N10/1kO) with a frequency of f = 1.6 Hz.

Function sequence for radio help call 

Depending on the programming, a radio help call can be made separate from or together with the emergency alarm.

The radio help call is started by:

• Pressing the "Trigger" button once
• Pressing the "Trigger" button twice within t = 3 s
• Operating the radio remote triggering transmitter twice within t = 3 s

The request for the radio help call is read in by the multifunction control unit and sent via multifunction CAN (CAN K) to the two-way radio (A49) (accessory) or the radio data transceiver (A49/5) (accessory).

The two-way radio or the radio data transceiver forwards the "Send" signal via direct line, taxi telephone antenna splitter (A28/12) (with code (386) Comfort telephony), direct line, cellular telephone system antenna amplifier/compensator (A28/3) (with code (386) Comfort telephony), direct line, mobile phone and stationary heater radio remote control antenna splitter (A2/53) (with code (386) Comfort telephony), and direct line to the multifunction antenna (A28/11).

The radio help call is then made via the multifunction antenna to the taxi main office. Depending on the programming, the actuation of a radio help call can occur "statically" or as a "pulse". With the "static" actuation, the discrete output at the multifunction control unit is switched to ground when the radio help call is made until the request for the radio help call is reset via the "Delete" button. With the "pulse" actuation, the discrete output at the multifunction control unit is switched to ground twice for t = 1 s with a break of t = 1 s between the pulses when the radio help call is made.

An active radio help call is ended by pressing the "Delete" button. The status of the "Delete" button is read in directly by the multifunction control unit. Often, however, it is necessary to restart the two-way radio in order to reset the radio help call in the two-way radio.

Function sequence for display of fault messages 

The fault messages are shown in the multifunction display (A1p13) of the instrument cluster (A1). Faults and malfunctions that occur are recognized and stored by the multifunction control unit and sent via interior CAN to the instrument cluster. In addition, the multifunction control unit cyclically sends data protocols via interior CAN to the instrument cluster.

The following faults and malfunctions are shown in the multifunction display:

• Interruption in the communication between the multifunction control unit and the instrument cluster
• Interruption of the line to the "Trigger" button
• Interruption of the line to the "Delete" button
• Alarm triggering recognized, but neither emergency alarm nor radio help call activated

During diagnosis via the diagnostic tester, a corresponding message is also shown in the multifunction display.

	Electrical function schematic for emergency alarm		PE82.25-P-2060-97DAA
	Overview of system components for taxi/rental vehicle		GF82.25-P-9890FL