Sierra Wireless MP 875 - Manual (Page 26)

MP 875 Modem User Guide
Note: To avoid RF interference
problems and possible damage
to the MP modem, do not power
on the MP modem before
connecting the RF antenna.
• Ensure that the RF antenna is mounted at least 20 cm
(8 inches) from vehicle occupants and bystanders.
• Ensure that all radio antennas (RF, GPS, CB radio, car
radio) are mounted at least 30 cm (12 inches) or more
apart.
Install the antennas and cables
Note: When connecting the cables, hand-tighten the connectors; do
not use tools.
To install the RF and GPS antennas:
1. Mount each antenna according to the instructions
provided with it.
2. Thread the antenna cables through the car to reach the MP
modem. Secure the cables as necessary.
3. Connect the RF antenna cable to the TNC connector on the
rear of the MP modem.
4. If you are using GPS, connect the GPS antenna cable to the
SMA connector on the rear of the MP modem.
GPS antenna
Serial Host USB Host
GPS
RF
Ethernet Host
RF antenna
Figure 2-5: The MP 875 modem’s SMA connector for the GPS antenna (top),
and the TNC connector for the RF antenna (bottom).
Step 3—Install the Power Harness
In a typical installation, the MP modem is connected to the
vehicle’s battery with the power harness. The MP modem
supports a voltage range between 9 volts, direct current (VDC)
and 36 VDC, and is designed for both 12 VDC and 24 VDC
vehicle electrical systems.
Note: Electrical installations are potentially dangerous and should be
performed by personnel thoroughly trained in safe electrical wiring
procedures for vehicles.
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