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SCP-FRC754-042-03H
T
ROUBLESHOOTING
Indication
Problem
FAULT
The FRC-754 processor
LED On
has detected a fault.
Troubleshooting based on customer-originated trouble reports
No Dial
• faulty RT or COT
Tone, Can
CU
not Dial
• facility short/open
• CO switch problem
• Tip/Ring reversed at
CO
Phone Does
• high-resistance
not Ring
subscriber line short
• faulty RT or CO CU
• loop length too long
Phone Does
• faulty subscriber
not Stop
instrument
Ringing
• faulty RT CU
• loop length too long
Can not
• subscriber problem
Hear, Can
• faulty RT or COT
not Be Heard
CU
FRC-754 List 4B
Table 10.
FRC-754 CU Troubleshooting Procedures
Action
Remove and reinsert the CU. If the FAULT LED does not extinguish, replace the CU.
1 Lift the subscriber pair at the network interface. If a dial tone is present and you can
place a call, refer the problem to the customer per local practice.
2 If you can not hear a dial tone or can not place a call at the network interface (with
the subscriber pair lifted), check for a 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 CU.
3 If the problem still exists, reinsert the original RT CU and replace the COT CU. Test
for operation.
4 If the problem still exists, refer the problem to the CO switch.
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 CU. If ringing is still not present, check a circuit on another CU. If ringing is still
not present, replace the RT Line Unit.
3 If ringing is still not present at the RT, reinsert the original CU 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 CU. Test again for
ringing at the network interface. If ringing is still not present, contact ADC technical
assistance per Product Support on inside back cover.
5 Verify the resistance of the copper loop between the RT Enclosure and the network
interface is less than 530 Ω.
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 CU. If ring
trip still does not occur, contact ADC technical assistancProduct Support on inside
back cover.
3 Verify the resistance of the copper loop between the RT Enclosure and the network
interface is less than 530 Ω.
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 CU.
3 If the level is still too low, reinsert the original RT CU.
4 Check the level at the COT coming from the CO switch. If it is correct, replace the
COT CU. If it is not correct, refer the problem to the CO regarding the switch.
5 If the level is still not correct, reinsert the original COT CU. Contact ADC technical
assistance per Product Support on inside back cover.
January 6, 2003
Verify Installation
9
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