Pre-power testing – Motorola PTP 500 User Manual
Page 13
Before plugging the RJ45 connector fitted to the lower LPU (or if not fitted the ODU)
into the PIDU check the following resistances at the RJ45;
a.
Check the cable resistance between pins 1&2, 3&6, 4&5 and 7&8 at the RJ45.
Check against column 2 in Table 1.
b.
Resistances for each pair should be within 1ohm of each other.
c.
Check the resistance between pins 1&3 and 4&7 at the RJ45. Check against
column 3 and 4 in Table 1.
d.
Ensure that there is greater than 100K ohms between pins 1 & 8 for all cable
lengths.
e.
Ensure that there is greater than 100K ohms between pin 1 and ODU ground for
all cable lengths.
f.
Ensure that there is greater than 100K ohms between pin 8 and ODU ground for
all cable lengths.
Table 1 - Resistance Table Referenced to the RJ45 at the PIDU Plus
Cat5E
Length
(meters)
Resistance
between pins
1&2, 3&6, 4&5
and 7&8
(ohms)
Resistance
between pins
1&3
(ohms)
Resistance
between pins
4&7
(ohms)
0
0.8
1.0
1.6
10
2.5
2.7
3.3
20
4.2
4.4
5.0
30
5.9
6.1
6.7
40
7.6
7.8
8.4
50
9.3
9.5
10.1
60
11.0
11.2
11.8
70
12.7
12.9
13.5
80
14.4
14.6
15.2
90
16.1
16.3
16.9
100
17.8
18
18.6
13
Pre-Power Testing
Identification of pin 1
1
8