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TC12 Installation, Commissioning & Maintenance Handbook
666/HE/43100/000
Page 192
Issue 10
(4) S4 - 600 Ohm/High Impedance Switch
If the switch is set to high impedance when it should be set to 600 Ohms, the
transmit signal for all OTUs on the line and the receive signal for the particular
OTU will be up to 3dB higher than if the switch was set correctly. The
characteristics of the line may also be affected.
If the switch is set to 600 Ohms when it should be set to high impedance this will
reduce signal levels and may upset the characteristics of the line.
6.5.3 Fault Finding at the Outstation
Symptom Possible
Reason
System Fault LED lit on Controller
Main Processor
Use handset to access fault log for
information on the type of fault that has
occurred, this may be an Integral OTU
fault
Watchdog LED On
Software not running correctly. Power
down and up again.
OTU not replying to control message
OTU Switch settings incorrect
OTU configured incorrectly via the
handset - repeat configuration.
Extended system bus cable
disconnected/faulty.
No control data - low line level,
interference BT lead disconnected /
faulty.
6.5.4 Lithium Battery
The outstation PCB is fitted with a Lithium Battery (B1, part number
418/4/97186/000). This battery must be
replaced
every
4
years.
There may be a label already on the battery showing the date the battery was
shipped. This should be covered with a label showing the
date the battery is
fitted
into the equipment. The replacement date is therefore
four years
after
the
date on the label.
WARNING
- Care should be taken when handling and disposing of Lithium
batteries. Refer to code of practice CP526.
6.5.5 Recommended Spares
Integral OTU kit
667/1/27004/000
Lithium battery
418/4/97186/000
LMU Spares (if equipped):
Current Transformer
667/7/25171/000
Voltage Monitoring Transformer
667/7/25172/000
Optional spares:
Handset terminal
667/4/13296/000