Sierra Wireless MP 875 - Manual (Page 24)

MP 875 Modem User Guide
Note: Tighten cables connected
to the MP modem by hand. Do
not use tools.
Ground the MP modem
Note: Electrical installations are potentially dangerous and should be
performed by personnel thoroughly trained in safe electrical wiring
procedures for vehicles.
Automotive installations usually provide a good quality
ground for each piece of electrical equipment. In most cases,
ground the MP modem by connecting the black ground wire
of the power harness to either the vehicle chassis or to the
negative terminal of the battery.
If a device connected to the MP modem, such as a notebook
computer, is not properly grounded, it may ground itself
through the cable connecting it to the MP modem. This creates
a hazard and could cause equipment damage. If you cannot
properly ground a device, a potential solution is to install a
fuse in the ground return wire.
The power harness has 5 A fuses on the red power wire and
the white ignition sense wire, but not on the black ground
return wire. (See
“Step 3—Install the Power Harness” on
page 26.)
You can also use a ground screw on the connector panel of the
MP modem. Use a 16-gauge wire if you choose to use a ground
screw. A ground screw is not required as long as the power
harness is properly grounded.
Power
I/O
If you are using a ground screw,
insert it here.
Figure 2-4: The ground screw connector on the connector panel.
Step 2—Mount the antennas and install
the cables
The MP 875 modem has one RF antenna connector and one
GPS antenna connector. The MP modem requires an RF
antenna to connect to the wireless network.
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