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Ground the mp modem – Sierra Wireless MP 875 User Manual

Page 28

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MP875 Modem User Guide

28

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Use the supplied mounting screws and washers to secure the 
MP modem through the holes along the edge of the case 
bottom.

Figure 3-3: Mounting the MP modem. Arrows indicate the mounting holes. The
front cover is open for illustration purposes only. Close it before mounting.

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 31.)