Taxi special system, function

Function requirements:

 No overvoltage/undervoltage

All functions of the taxi special system are monitored and actuated by the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9).

In general, the following functions (taxi - code 450) are supported:

 Power supply for two-way radio (A49)

 Power supply for taximeter control unit (A67n1) or conventional taximeter (A50)

 Data exchange with the taximeter control unit (A67n1) via the serial interface (RS485) or cabling with the conventional taximeter (A50) via four lines

 Power supply for interior socket (X58/1)

 Power supply for glove box socket (X29/6), which is a DIN socket below the glove compartment

 Actuation of the roof sign lamp (E14/4)

 Actuation of the rear ashtray illumination (E9/10) as soon as at least the standing lights are switched on

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Switch the roof sign lamp (E14/4) on/off

The roof sign lamp (E14/4) is switched on and off via the instrument cluster (A1) using the buttons of the multifunction steering wheel or via the taximeter control unit (A67n1):

 Via the instrument cluster:
With the buttons of the multifunction steering wheel, call up SETTINGS menu,
scroll to TAXI ROOF SIGN submenu,
switch the roof sign off or on there.

 Via the taximeter control unit:
This function is only possible if the roof sign is set to ON via the instrument cluster and the taximeter is in the FREE status.
To switch on and off, press and hold the right button at the taximeter until the roof sign lamp indicator in the taximeter lights up or goes out.

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Special features of interior illumination

 When a front door is opened, the front dome lamp (N70e1) and the rear interior lamp (E15/3) are actuated by the overhead control panel control unit (N70).

 When a rear door is opened, only the rear interior lamp (E15/3) is actuated.

 When a vehicle door is open, the interior illumination switches off after two minutes (after five minutes on vehicles without taxi equipment).

 In the PAYMENT mode, the interior lights are automatically switched on if the sensor unit for light activation (B32/1) reports "dark" and the speed of the vehicle is  5 km/h.

Video system

For interior protection, a video system can be connected. For this purpose, the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) has the door contact output. The video system can be actuated via the door contacts using this. In addition, the SVMCU [MSS] has an input with which the interior illumination can be activated by the video system.

Programmable options

The following options can also be activated via the Star Diagnosis tool:

 Switching on/off the roof sign lamp (E14/4)

upon receipt of the CAN message "Open/close central locking"

 Programming the threshold value for undervoltage shutoff of the roof sign lamp (E14/4) and the other supply outputs

 Allow undervoltage shutoff of the power supply from taximeter control unit (A67n1) yes/no?

 Automatic locking of the vehicle at speeds over 3 km/h

 Evaluation of the seat occupied recognition

Undervoltage shutoff

If the on-board voltage sinks below the undervoltage threshold value (11.5 V is preset) for longer than 5 s, all supply outputs of the special vehicle multifunction control unit (SMVCU [MSS]) (N26/9) are switched off (exception: taximeter).

The "undervoltage shutoff" status is automatically ended if the on-board voltage exceeds U = 13 V.

Networking

For the data exchange (e.g. of the vehicle speed and wheel speed signal), the special vehicle multifunction control unit (SMVCU [MSS]) (N26/9) is connected to the CAN interior (cf. networking of the components).