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6. Common Problems
Common Failures and Solutions
No. Failure
Cause
Solution
1
PWR power supply
indicator lamp not
lightening
1.Power supply not properly
connected
2.Protector tube damaged
3. -48V DC input tie-line in
reverse connection
4.Internal power supply circuit
with failure
1.Check power switch and jack
2.Replace protector tube 3.Correct -48V
power supply line connection
4. Returned to the manufacturer for
repair.
2
LOF out-of-frame
alarm lamp lightening
1.Optic interface not clean
2.Optic fiber not well inserted
3.Wrong clock setting
4.Time slots of the devices at
two ends not conformance
5.Internal circuit damaged
1. Clean the connector of optic interface
2. Insert the SC connector in place
3. Refer to the description on rear panel
4. Returned to the manufacturer for
repair.
3
LOS data loss alarm
lamp lightening
1. Optic fiber in wrong
interconnection
2.Optic fiber not well inserted
3.Optic fiber broken
4.Internal circuit damaged
1. Correct the connection
2. Insert the SC connector in place
3. Check optic cable
4. Returned to the manufacturer for
repair.
4
TXD lamp not
lightening
V.35 interface not well
connected or the router etc. not
turned on.
1. Check the connecting line and
terminal device
