Motorola PTP 500 Pre-Power Testing, Cat5E Resistance, Between pins, Meters 3&6, 4&5, Ohms

Pre-Power Testing

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.

Cat5E	Resistance	Resistance	Resistance
Length	between pins	between pins	between pins
(meters)	1&2, 3&6, 4&5	1&3	4&7
	and 7&8	(ohms)	(ohms)
	(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

Table 1 - Resistance Table Referenced to the RJ45 at the PIDU Plus

8

1

Identification of pin 1

13