CTP Systems CTPhone 1900, Applications Manual

Page: 92 / 132

5-4 DOC00101-01
Diagnostics and Troubleshooting
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Checking CTPhone Controller-Base Station Cable Distance
Step Procedure
1 Make sure all wiring between the CTPhone Controller, MDF/
IDFs, and base stations is complete. In addition, make sure
primary protectors are installed, if they are required. (For
information on primary protection requirements for UL1459
compliance in the United States, see Appendix A; see also
the caution on page 3-5.)
2 Disconnect the CTPhone Controller from power.
3 Disconnect the 25-pair cables from P1 and P2 on the
CTPhone Controller. (Make sure to perform this step before
step 4.)
4 Disconnect the transmit and receive cables from the base
station and connect them into each end of the RJ-11 line
adapter.
5 Set the multimeter to ohms scale with a resolution of units of
ohms.
6 To check the distance to base station one, connect the multi-
meter probes between pins 20 and 46 of the 25-pair cable
that connects to P1 on the CTPhone Controller. If no reading
or a high resistance is reported, measure between pins 20
and 21.
A reading should register at only one of the pairs and must
be less than the values listed in Table 5-A.
7 Based on which pins returned a valid reading in step 6, check
readings between the following pairs:
Valid reading pins 20/46 – measure pins 21/45
Valid reading pins 20/21 – measure pins 45/46
The readings between the sets of pins you measure should
be similar.
8 To check the distance to base station two, connect the multi-
meter probes between pins 24 and 50. If no reading or a high
resistance is reported, measure between pins 24 and 25.
A reading should register at only one of the pairs and must
be less than the values listed in Table 5-A.