Progressive Electronics PE945 Manual De Instrucciones página 13

Troubleshooting (cont'd)
Symptom*
RFI (radio
frequency
interference)
Intermittent or
variable current
* Wet cables may cause most of these symptoms and may cause multiple symptoms to
appear at the same time.
Possible Cause /
Troubleshooting Step
Split pair
Wet cables or a bad
connection
Explanation
An unbalanced pair near a radio transmitter will
be prone to RFI. Adding radio filters can reduce
the interference on the line (the symptom), but
does not solve the imbalance (the problem). To
troubleshoot, break the circuit down into
sections and check each section for split pairs
or a resistive imbalance.
Improperly removed bridge taps may also
introduce RFI. Bridge taps, which were once used
for party-line service (multiple users sharing a
cable pair), were often disconnected but left in
place, with a stub section of cable still connected.
This stub section can act as an antenna and
induce radio signals into the circuit.
If accompanied by noise, the cause is usually
wet cables.
If no noise is present, the cause is probably a
bad connection in a cross-connect or a bad
connection at the central office.
PE945
13