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FXS/DID Dropping Active Calls


We are migrating four FXS/DID trunks from a Nortel to a Cisco 2911 gateway. The CO switch is a Lucent 5ESS set for wink start.

The calls are completeing sucessfully but all four active calls drop within 10 seconds. Not all at the same instant, each varies.

Debug shows the CO switch is disconnecting, not the 2911 gateway.

Is the CO switch looking for something after the phone call is answered and audio path is established?

Hall of Fame Master

Re: FXS/DID Dropping Active Calls

Send port config and relevant debug.


FXS/DID Dropping Active Calls

Thank you, here is the config. I will get a relevant debug when we test again. We have researched this extensively and can not find the solution.

We are completing the calls and establishing audio for 10 seconds. For our next test, we would ike to validate answer supervision. Perhaps the 5ESS is not seeing the offhook polarity reversal or we need to turn it off. Does the 5ESS need to see polarity reversal before it will establish the audio path? Is it safe to assume that polarity reversal is not an issue since we have a voice path? Since the voice path is estbablished what timers could expire at roughly 10 seconds? Is H323 still involved after the voice path has completed?

Foreign Exchange Station 0/2/0 Slot is 0, Sub-unit is 2, Port is 0
Type of VoicePort is DID-IN
Operation State is DORMANT
Administrative State is UP
No Interface Down Failure
Description is Analog FXS/DiD 706.259.2450 DINA circuit
Noise Regeneration is enabled
Non Linear Processing is enabled
Non Linear Mute is disabled
Non Linear Threshold is -21 dB
Music On Hold Threshold is Set to -38 dBm
In Gain is Set to 0 dB
Out Attenuation is Set to 3 dB
Echo Cancellation is enabled
Echo Cancellation NLP mute is disabled
Echo Cancellation NLP threshold is -21 dB
Echo Cancel Coverage is set to 128 ms
Echo Cancel worst case ERL is set to 6 dB
Playout-delay Mode is set to adaptive
Playout-delay Nominal is set to 60 ms
Playout-delay Maximum is set to 1000 ms
Playout-delay Minimum mode is set to default, value 40 ms
Playout-delay Fax is set to 300 ms
Connection Mode is normal
Connection Number is not set
Initial Time Out is set to 15 s
Interdigit Time Out is set to 10 s
Call Disconnect Time Out is set to 60 s
Ringing Time Out is set to 180 s
Wait Release Time Out is set to 30 s
Companding Type is u-law
Region Tone is set for US

Analog Info Follows:
Currently processing none
Maintenance Mode Set to None (not in mtc mode)
Number of signaling protocol errors are 0
Impedance is set to 600r Ohm
Station name None, Station number None
Translation profile (Incoming): INCOME-DDI
Translation profile (Outgoing):
lpcor (Incoming):
lpcor (Outgoing):

Signal Type is wink-start
Dial Out Type is dtmf
In Seizure is inactive
Out Seizure is inactive
Digit Duration Timing is set to 100 ms
InterDigit Duration Timing is set to 100 ms
Pulse Rate Timing is set to 10 pulses/second
InterDigit Pulse Duration Timing is set to 750 ms
Clear Wait Duration Timing is set to 400 ms
Wink Wait Duration Timing is set to 200 ms
Wait Wink Duration Timing is set to 550 ms
Wink Duration Timing is set to 200 ms
Delay Start Timing is set to 300 ms
Delay Duration Timing is set to 2000 ms
Dial Pulse Min. Delay is set to 140 ms
Percent Break of Pulse is 60 percent
Auto Cut-through is disabled
Dialout Delay is 70 ms
Hookflash-in Timing is set to 0 ms


FXS/DID Dropping Active Calls

Do you remember what you did to resolve this issue?  I have a customer with pretty much the exact same problem.  Thanks.


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