User guide

AirLink MP User Guide
34 2130795
The battery (red) and ignition sense (white) wires in the power harness include
5 A fuses. The black ground wire is not fused. (See Ground the power harness on
page 35.) Replacement power harnesses are available from Sierra Wireless.
Note: The battery cable used for a car, truck, or other mobile connection must be less than
3 meters in length.
Vehicle installation
This section applies to installing the MP modem in a vehicle. If you are installing it
in an office, see Office installation on page 36.
Ignition sense on/off wiring
This section only applies to installing an MP modem in a vehicle. If you are
installing the MP modem in an office building, use the AC/DC adapter.
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.
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.
Note: The battery cable used for a car, truck, or other mobile connection must be less than
3 meters in length.
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.
• When the ignition sense line is pulled low (less than 2 V), the MP modem
performs a controlled shutdown sequence (under software control), de-regis-
tering and saving any relevant operational data before powering off.
Ignition sense options
There are three ways to connect the ignition sense wiring:
Black unfused wire
(Ground)
White wire
(Ignition sense)
Red wire
(Battery)
MP modem
5 A fuses (on red
and white only)
Switch (vehicle
ignition key, or
separate)
Vehicle battery