User manual

DTS Broadcast PDH Microwave Digital Radio User Manual
-86-
Note. The most common reason for this alarm occurrence will be due to a link fade, such as that
occurring during excessive rainfall.
BER alarm
Alarm condition indicates the received BER has exceeded the preset Alarm threshold. The action
required to resolve the fault will depend upon all the accompanying alarms. Recommend use of
loopback features to locate the problem.
Note. The most common reason for this alarm occurrence will be due to a link fade, such as that
occurring during excessive rainfall.
Cable Fault
Alarm condition indicates microprocessor communications between the IDU and ODU have
failed.
The fault is most probably with the cable connection, it may be either open or shorted. Use of a
multi-meter to measure DC cable resistance will determine if the cable is open or shorted:
1. Disconnect power to the IDU
2. Remove the N-type ODU connector from the IDU
3. Measure the DC resistance between the centre pin and the outer of the N-type connector
terminating the cable;
If resistance is between 1 M and 10M
• This is correct
• Suspect IDU or ODU circuitry
• Replace IDU
• If alarm persists, swap replacement IDU for original and replaces ODU.
If resistance is less than 1M :
• Check the cable thoroughly over whole length and at both ends for damage or reasons that
would cause low cable resistance.
• If in doubt reterminate both ends of cable with new N-type connectors.
• Remeasure cable resistance (with it disconnected at both ends), resistance should be
unmeasurable or open circuit.
• If cable resistance is unchanged, replace entire cable run, terminating with new N-type
connectors.