PairGain PG-Flex, Manual

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Troubleshooting
100
Channel Unit Troubleshooting
Table 31 provides troubleshooting procedures based on indications displayed by the front panel
LEDs of a channel unit and customer reports.
Table 31. Channel Unit Troubleshooting
Indication Problem Action
FAULT LED
ON The 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 Not Dial • faulty RT or COT
channel unit
• facility short/open
• CO switch problem
• faulty customer
instrument/wiring
1 Verify that dial tone is present at the CO. (COT Looking-In or Bridging).
2 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.
(RT Looking-In or Bridging).
3 If the problem still exists, refer the problem to the CO switch.
4 If you cannot hear dial tone or cannot place a call at the network interface
(with the subscriber pair lifted), check for dial tone at the RT. If 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.
5
If the problem still exists, reinsert the original RT channel unit and replace
the COT channel unit. Test for operation.
Phone Does
Not Ring • high-resistance
subscriber line short
• faulty RT or CO channel
unit
• loop length too long
• 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 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, reinsert 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 Support” on page 113.
5 Verify the resistance of the copper loop between the RT Enclosure and the
network interface is less than 530
Ω
.
Phone Does
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 Support” on page 113.
3
Verify the resistance of the copper loop between the RT Enclosure and the
network interface is less than 530
Ω
.