Sierra Wireless MP 875 User Manual
Page 27
Hardware and Software Installation
Note: Connector part numbers:
39-01-2040 or 39-01-2045. Pins
part number: 39-00-0039.
Note: Do not install an on/off
switch on the main (red) battery
line, or connect the white ignition
sense wire to the red battery
wire. Both configurations bypass
the MP modem's controlled
shutdown sequence, and may
cause data loss and subsequent
power-on problems. Incorrect
wiring may also drain the vehicle
battery.
Power connector
The power harness connects to the MP modem with a Molex
connector.
Power connector (Molex) pinouts
The pinouts for the Molex connector on the power harness are:
White wire
(Ignition sense)
Red wire
(Battery)
Unused
Black wire
(Ground)
Figure 2-6: Pinouts for the power harness.
The battery (red) and ignition sense (white) wires in the power
harness include 5 A fuses. The black ground wire is not fused.
(See
power harnesses are available from Sierra Wireless.
Ignition sense on/off wiring
The MP modem’s power on/off is controlled by the ignition
sense line (white wire) using internal software, rather than a
hard on/off switch on the red power line. The red, black, and
white wires connect to the battery and ignition switch as
shown in the power harness wiring diagram.
Switch (vehicle
Red wire
5 A fuses (on red
ignition key, or
(Battery)
and white only)
separate)
Black unfused wire
(Ground)
White wire
(Ignition sense)
MP modem
Vehicle battery
Figure 2-7: Wiring for the power harness.The white wire is the ignition sense.
•
When the white ignition sense line is pulled high (5 to
36 V), the MP modem powers on.
Rev 1.1 Aug.07
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