Summary:ASTERISK-12418: Duplicated Digit 9 DTMF Relay/ Origination from O2 Germany
Reporter:Mazhar Abbas (mazhar996)Labels:
Date Opened:2008-07-20 20:30:25Date Closed:2011-06-07 14:02:52
Versions:Frequency of
Environment:Attachments:( 0) DTMF-digit9.txt
Description:Hi there,
I am facing problems with DTMF relay when Digit 9 is pressed. I am using rfc2833 , all digits are relayed properly except the digit 9
9 is mostly doubled and sometimes three times. I have tested it many times and noticed that whenever digit 9 is entered its relayed twice or thrice.
actually at times its relayed properly too. but most of the times its duplicated.


The call scenerio is like this: I have hired DID numbers from 3U Germany.
When I call the DID using my PSTN phone (DTAG) or using my T-Mobile or Vodafon or E-Plus mobiles, I have no problems. But when i use an O2 Germany Mobile to dial the did i face this problem.
 Strange is that at times 9 is passed correctly but most of the times its duplicated.

Attaching the debug report.

I thought it could be asterisk issue because I saw something like “DTMF end '9' has duration 40 but want minimum 80” in the dtmf debug. I assumed if I changed it to minimum 40ms which I found to be standard in most cases when searching the web.
  I changed it and recompiled the asterisk. Now I do not see this message “DTMF end '9' has duration 40 but want minimum 80” but still I receive digit 9 duplicated at times. The strange thing is really that at times its received properly and at times its duplicated.
    And its definitely not mobile set. I have tried with 3 different mobile sets. I ran the dtmf debug again and I think that the problem is really at O2 or 3U network side (that’s an assumption, apologies if its wrong). I am attaching the debug trace for dtmf.

           I dialed the number 009230095. The second time digit 9 was pressed (line 205) it was accurate, only a single digit.  But previously, it was received twice (line 64 and line 82 ).

Both times it says

DTMF begin '9' received on SIP/3U.net-08204fc8
Comments:By: Leif Madsen (lmadsen) 2008-10-14 12:16:11

Are you still getting this issue with the latest version of Asterisk 1.4? Are you getting this issue with any other providers? Is there a chance this isn't actually an issue with Asterisk but rather an issue with the provider mentioned? It seems quite odd that you would be fine with all DTMF other than 9...

By: GERD GERD (gerd1000) 2008-10-20 05:47:32

I could confirm that this behaviour is O2 (a german GSM network provider)
specific and  independent of GSM phone and it is only related to '9'.
It gets even worse if the user is dialing a sequence of 9s.
If your asterisk is connected via SIP to 3U then
either you talk to 3U (or to the vendor of their equipement (TELES?)) for
doing some changes in their DTMF recognition or you
try to convince O2 to solve it.

By: GERD GERD (gerd1000) 2008-10-20 05:51:18

I would also like to note, that I did not test with the asterisk builtin DTMF
decoder. So, there _may_ be a problem, too.

By: Leif Madsen (lmadsen) 2008-10-21 09:59:44

Would it be possible to get a wireshark (pcap) trace of the issue at hand for further debugging?

By: Jason Parker (jparker) 2008-11-18 14:33:34.000-0600

We're going to need to see that pcap trace, or we're going to have no choice but to close this.

By: Joshua C. Colp (jcolp) 2008-12-08 09:47:02.000-0600

Unfortunately without a wireshark capture it is going to be difficult to track this down, and from the debug information provided it does seem to be a problem with the inband detector on the provider side.