Duplicated DTMF?

Unanswered Question
Aug 31st, 2009


I am looking for help on a case where the ATA is actually hearing duplicated tones from the

connected analog phone.

An example:

The analog phone connected to the PAP2T dials 12345 but the PAP2T is then calling 1122334455...

What can be causing the ATA to hear duplicated tones and how can that be workarounded?

I tried increasing the FXS input gain but this did not solved the issue....



I have this problem too.
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Patrick Born Tue, 09/01/2009 - 04:19

Hi Luca,

Please have them:

1. Test the same phone on the other phone port of the PAP2T.

2. Try another analog telephone, a different model phone would be best for this test

3. Enable debugging and send a log from when this happens:


4. Provide the device's configuration:





lbuongio Wed, 09/02/2009 - 07:43


Thanks for the prompt reply.

I will try to get the log file and post it here.

At the same time if another analog phone is working fine on that same FXS port

is there any tweaking that can be done to try to solve the problem ?

Many thanks again for the support,


Patrick Born Wed, 09/02/2009 - 12:01

Hi Luca,

Verify that the settings for the deployed geography match these in the SPA400 Caller ID Localization doc: https://www.myciscocommunity.com/docs/DOC-7414

You can make changes that affect the Line 1 and Line 2 ports in the Regional tab > Miscellaneous section.

If one analog phone model works, it's best to use that model going forwards.




lbuongio Mon, 09/07/2009 - 02:14


In this particular case the problem is between a PAP2T and the connected analog phone.

The PAP2T is really not understanding correctly the numbering DTMF tones sent by the phone.

Anyway today I was again browsing the net for a tip and found this:


Would it be possible than that the PAP2T too is listening to both the telephone tone and the tone

it is re-producing and sending?

In such case changing the DTMF tx method to info only should fix the issue I suppose...

Thanks and regards,


Patrick Born Wed, 09/09/2009 - 07:55

Hi Luca,

If you get a chance to test this, please share any results.

Additionally, verify that Line N > Audio Configuration > DTMF Tx Mode: strict




lbuongio Thu, 09/10/2009 - 10:01


I will update this discussion as soon as I have any update from the customer.




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