Installation and Test
363-704-104-01, Revision 01
10
June 22, 1998
FLC-704 List 4
Troubleshooting
provides troubleshooting procedures based on indications displayed by the front panel indicators of the
FLC-704 List 4 channel unit.
Table 10.
FLC-704 List 4 Channel Unit Troubleshooting
Indication
Problem
Action
FAULT LED
ON
The FLC-704 processor
has detected a fault.
Remove and reinsert the Channel Unit. If the FAULT LED does not extinguish, replace the
Channel Unit.
Troubleshooting based on customer-originated trouble reports
No Dial tone,
Can’t Dial
•
faulty RT or COT
Channel Unit
•
facility short/open
•
CO switch problem
•
Tip/Ring reversed at
CO
1
Lift the subscriber pair at the network interface. If dial tone is present and you can place
a call, refer the problem to the customer per local practice.
2
If you cannot hear a dial tone or cannot place a call at the network interface (with the
subscriber pair lifted), check for dial tone at the RT. If a dial tone is present, check the
pair between the RT and the network interface. If no dial tone is present, replace the RT
Channel Unit.
3
If the problem still exists, re-insert the original RT Channel Unit and replace the COT
Channel Unit. Test for operation.
4
If the problem still exists, refer the problem to the CO switch.
Phone
Doesn’t Ring
•
high-resistance
subscriber line short
•
faulty RT or CO
Channel Unit
•
loop length too long
1
Lift the subscriber pair at the network interface. If ringing is present, refer the problem
to the customer per local practice.
2
If ringing is not present, check for ringing at the RT. If ringing is present, check the pair
between the RT and the network interface. If no ringing is present, replace the RT
Channel Unit. If ringing is still not present, check a circuit on another Channel Unit. If
ringing is still not present, replace the Line Unit.
3
If ringing is still not present at the RT, re-insert the original Channel Unit and Line Unit.
Test for ringing at the COT.
4
Test for ringing into the COT from the CO switch. If no ringing is present, refer the
trouble to the CO switch. If ringing is present, replace the COT Channel Unit. Test again
for ringing at the network interface. If ringing is still not present, contact PairGain
technical assistance per
.
5
Verify the resistance of the copper loop between the RT Enclosure and the network
interface is less than 530
Ω
.
Phone
doesn’t stop
ringing
•
faulty subscriber
instrument
•
faulty RT Channel
Unit
•
loop length too long
1
Test for ring trip at the network interface. If the ringing is tripped, refer the trouble to
the customer per local practice.
2
If the ringing is not tripped, test for tripping at the RT. If ring trip does occur, check the
loop for excessive length. If ring trip does not occur, replace the RT Channel Unit. If
ring trip still does not occur, contact PairGain technical assistance per
.
3
Verify the resistance of the copper loop between the RT Enclosure and the network
interface is less than 530
Ω
.
Can’t Hear,
Can’t Be
Heard
•
subscriber problem
•
faulty RT or COT
Channel Unit
1
Lift the subscriber line at the network interface and check the signal level. If correct,
refer trouble to the customer per local practice.
2
If the level is too low, check the level at the RT. If the level is correct at the RT, check
the pair between the RT and the network interface. If the level is too low at the RT,
replace the RT Channel Unit.
3
If the level is still too low, re-insert the original RT Channel Unit.
4
Check the level at the COT coming from the CO switch. If it is correct, replace the COT
Channel Unit. If it is not correct, refer the problem to the CO regarding the switch.
5
If the level is still not correct, re-insert the original COT Channel Unit. Contact PairGain
technical assistance per
.
