Summary:ASTERISK-06991: DTMF Tones ("talkback") on all kind of Channels
Reporter:hobbystern (hobbystern)Labels:
Date Opened:2006-05-17 13:55:57Date Closed:2011-06-07 14:07:48
Versions:Frequency of
Description:I logged everyday randomly occuring DTMF Tones on all kind of my Channels, i use Zap/SIP/mISDN.
The Log looks like this :

May 17 07:04:54 DTMF[18606] channel.c: SIP/pbx1-d0c5 : 9
May 17 07:04:55 DTMF[18606] channel.c: SIP/pbx1-d0c5 : 3
May 17 07:46:43 DTMF[18776] channel.c: Zap/1-1 : 2
May 17 08:59:02 DTMF[19426] channel.c: Zap/1-1 : 4
May 17 08:59:17 DTMF[19426] channel.c: Zap/1-1 : 7
May 17 08:59:45 DTMF[19426] channel.c: Zap/1-1 : 4
May 17 09:01:06 DTMF[19426] channel.c: Zap/1-1 : 1
May 17 09:25:37 DTMF[19859] channel.c: SIP/10-3b44 : #
May 17 10:05:38 DTMF[20289] channel.c: mISDN/1-u20 : 5
May 17 10:55:41 DTMF[20653] channel.c: SIP/20-c923 : 1
May 17 11:39:08 DTMF[21128] channel.c: SIP/20-dd39 : A
May 17 11:39:39 DTMF[21128] channel.c: SIP/20-dd39 : 9
May 17 11:51:05 DTMF[21374] channel.c: mISDN/2-1 : 3
May 17 11:51:05 DTMF[21374] channel.c: mISDN/2-1 : 5
May 17 11:51:33 DTMF[21374] channel.c: mISDN/2-1 : 3
May 17 11:51:33 DTMF[21374] channel.c: mISDN/2-1 : 5  
May 17 11:51:43 DTMF[21374] channel.c: mISDN/2-1 : 3  
May 17 11:51:43 DTMF[21374] channel.c: mISDN/2-1 : 5  
May 17 11:53:19 DTMF[21504] channel.c: SIP/10-396c : 1
May 17 12:07:48 DTMF[21755] channel.c: mISDN/1-1 : 3  

I have read and understood the meaning of "talkback" - but i cant fix my problem with relaxdtmf.


I use :

Asterisk 1.2.6 - patched with "snom pickup patch" (*) (Zaptel 1.2.5) with a Beronet TDM40B, 2 x Acer HFC with mISDN (0.3.0 RC27) on Debian with kernel 2.6.15-686.

(*) = http://bugs.digium.com/file_download.php?file_id=9459&type=bug

I have tried many times to solve the problem, but i cant figure out WHAT is producing this DTMF Tones.

My Tries :

- All Clients must use the SAME DTMF Mode, i guess. So i set them from INFO to RFC2833
- I enabled a extra DTMF Logfile via logger.conf to control the appearance of these strange DTMF Tones
- I asked in the Asterisk Mailing List where someone told me it is called "talkback" - so i learned about it

Comments:By: Serge Vecher (serge-v) 2006-05-17 14:05:45

hobbystern: any particular reasons for marking the bug "private"?

By: hobbystern (hobbystern) 2006-05-17 15:11:56

No reason, i am just not sure if its ok to call my problem a bug. But i cant find any other support for this. Is it ok to decline it as public? Greets, Stefan

EDIT : I am not using Kernel "686" - please cange it to k7, just seen it, sorry.

By: Serge Vecher (serge-v) 2006-05-17 15:23:26

well: the "private" status is really designed for bugs with sensitive information and limits exposure for this issue (which reduces the chance it will get solved).

First of all:
1) What is a "talkback"? I don't see anything unusual in the console log you've provided.
2) Can you please upgrade your Asterisk installation to latest 1.2 branch code (rev. > 27000) and check out latest mISDN 0.3.0 code in /team/crichter/channels on at svn.digium.com and see if that fixes the issue?

By: hobbystern (hobbystern) 2006-05-17 15:49:17

Ok, public is right, i will remember.
a) talkback means "talkoff", sorry, my fault.
That means that something on my linux generates DTMF Tones, these tones arent pressed, they are randomly generated and occured within the call and can cause some things like "transfer" or some other bad behaviour.

b) Yes, sure i can, i will upgrade * to the latest 1.2.8, mISDN is another problem, i am in discussion with crich from mISDN at the german-ipp-forum, the latest 0.3.1 RC3 from SVN "stands under the suspicion" to cause an Kernel Oops, so i have downgraded to the last, on my machine stable running, 0.3.0 RC27 to avoid such new problems and wait for the stable 0.3.1

But you are right, i should update and check the problem again.

Have you ever heard another guy experience such a problem ?

Please excuse my failure on the first bug at digium, i will learn for the next time

Greets, Stefan

By: Joshua C. Colp (jcolp) 2006-05-17 16:21:55

If you're getting DTMF on SIP and you're explicitly using RFC2833, then that has to be coming from the device. This is because Asterisk only fires up a DSP (this is what is used to detect the inband DTMF) only if you're using inband or auto. OR other weird things are happening. OR people really are hitting DTMF accidentally (I know I do sometimes).

By: hobbystern (hobbystern) 2006-05-18 01:45:31

SIP and RFC2833 - i wish it would be so easy ;)
I get the DTMF Tones on any kind of Channel, on ATAs - connected via SIP, on ZAP Devices (DECT Phones) - even in a fax connection via ZAP->ISDN i logged DTMF Tones, as you can see in the Logfile above.

People are pressing DTMF, of course, but not so often as it is logged, i noticed it in calls with my private Phone (connected via ATA) - i heard it yesterday on my DECT Zap at work :(

Can i make some changes to avoid a fault of myself, can i use only INFO to increase failures with my settings?

If I am going off topic with my questions so please tell me - so we can close the "BUG" which is probably no bug, i guess.

Big Thanks from Germany ! Stefan

By: Joshua C. Colp (jcolp) 2006-05-18 09:54:30

I'm going to close this as like you did say, it's not really a bug... at least that I can determine. If you really do find one feel free to reopen it.