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Wrong DTMF detection

Unanswered Question
Aug 19th, 2014
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Dear All,


I have Cisco Voice router 2801 with Two FXO ports and we have terminated two PSTN lines over it. Suddently, we are facing some DTMF detection issues.


Once the Router give us the dial Tone and we tried to dialed the desired numbers but unfortunately some times router recived the wrong digits. Successful ratio is 30% means 3 calls are passing correctly out of 10.


For Example:


Dailed: 923332631696

Recived Sample 1: 92233326631116

Recived Sample 2: 9223266


Please help me to sort out this issue. Thanks.


Note: its works perfectly since couple of years.




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Suresh Hudda Tue, 08/19/2014 - 23:31
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    2017 IP Telephony

You are using ip phone or analog phone to dial and are you facing this issue from all phones or any specific phone model ?

I have seen this issue when dialing from analog phone due to different pulse/tone settings on phone.


Muhammad Hassan Tue, 08/19/2014 - 23:49
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Suresh, Thanks for your Response.


I am using analog phone in order to reach the router. Below are the call flow


Analog Phone ---> FXO (PSTN Line) ----> Voice Dial Peer VOIP (SIP)


Please let me know if you any settings. I have tried to change dial type to pulse from DTMF but not much improvement.



Suresh Hudda Wed, 08/20/2014 - 03:37
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Can you test dialing on speaker mode or plz test with other/new analog phone.


Muhammad Hassan Wed, 08/20/2014 - 03:57
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Already tested via different phones even via different country.


I suspected the issue related to Telco side. It seems they are sending DTMF at very high Decibel level.


If anyone face the same issue, please share the experience.


Thanks a lot!

Muhammad Hassan Wed, 08/20/2014 - 04:16
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Please find the below requested info


dial-peer voice 111 voip
 destination-pattern 9T
 session protocol sipv2
 session target ipv4:X.X.X.X
 dtmf-relay rtp-nte

voice-port 0/3/1
 dial-type pulse
 timeouts call-disconnect 0
 timeouts ringing 30


problemchild27 Wed, 08/20/2014 - 04:23
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Instead of  " rtp-nte " can you try " sip-notify " and reload the router post wr memory




Muhammad Hassan Wed, 08/20/2014 - 05:01
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I tried this but obseverd same behaviour. like below


Dailed: 923332631696

Recived Sample 1: 2333631696

Recived Sample 2: 923332631696 - correct

Recived Sample 3: 923332631696 - correct

Recived Sample 4: 9233631696

Manish Prasad Wed, 08/20/2014 - 07:14
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Try putting connection plar opx 923332631696 under the voice port.

If you dont have any POTS dial-peer pointing to FXO port , you need it to make oubound call from that FXO port.

Muhammad Hassan Thu, 08/21/2014 - 23:02
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Thanks Manish


This workaround already implemented but i want to sort out the DTMF issues. we have to dial several different numbers on daily basis.



Manish Prasad Fri, 08/22/2014 - 03:04
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Can you attach debug vpm signal and debug voice ccapi inout after enabling caller id on fxo port.


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