Chapter 2: System hardware
101
Table 75 :Breather vent part number
Cambium description
Cambium part number
Breather Vent - PG16 size (Qty. 10)
N000000L141A
Et her net cab le t est ing
This section describes a procedure for testing the RJ45 Ethernet cables used for Main and Aux port
connectivity on 450i and 450m radios.
To test a cable, perform the following instructions:
1. Check the resistances of the cable and radio installation using a digital multimeter (DMM).
2. Disconnect the drop cable from the power source (EPI or mains adapter) first; keep the radio
connected and test the resistances looking towards the radio. Test access can be made via any of
the following:
l
Directly onto the pins of the RJ45 plug.
l
Using a commercially available RJ45 breakout board.
Measure
between
Approximate resistance
Example
Wire 1 and
wire 2
Wire 3 and
wire 6
Wire 4 and
wire 5
Wire 7 and
wire 8
1 ohm + 2 ohms per 10 m of cable
Maximum difference between any two readings 0.3 ohms +
0.3 ohms per 10 m of cable
A cable with a single LPU but no radio will read about 3,600
ohms.
A cable with a single 1000SS but no radio will read about
7,200 ohms.
For a 20 m cable:
Approximate resistance
= 1 ohm + 2x 2 ohms
= 5 ohms
Maximum difference
between readings
= 0.3 ohms + 2x 0.3 ohms
= 0.9 ohms
Wire 1 and
wire 3
Wire 1 and
wire 4
Wire 1 and
wire 7
Wire 3 and
wire 4
Wire 3 and
wire 7
Wire 4 and
wire 7
> 20 Kohms
Summary of Contents for PMP 450 Series
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