[asterisk-users] Problem with sounds DTMF's phone keys

[Alex Villací­s Lasso]

Danny Nicholas escribió:
> Could it be your using option X when you have no extensions for the user to
> exit to (therefore when they press dtmf instead of one and done, they just
> keep going?)
>
>  
>
>   _____  
>
> From: asterisk-users-bounces at lists.digium.com
> [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Moises Silva
> Sent: Monday, November 16, 2009 2:40 PM
> To: Asterisk Users Mailing List - Non-Commercial Discussion
> Subject: Re: [asterisk-users] Problem with sounds DTMF's phone keys
>
>  
>
> On Mon, Nov 16, 2009 at 3:27 PM, Diana Lopez <dlopez at palosanto.com> wrote:
>
> Hello everybody,
>
> I need help, I have a problem with conferences in asterisk, when many
> people are in a conference sometimes there're users pressing phone keys
> and this action emits a sound (DTMF of the phone keys), so, I need to
> find the way of not listening this sound.. I'm using
> MeetMe(variable,pFX).. I tried whithout "F" but it doesn't work because
> users continue listening de DTMF's sounds...
>
> But the way, I'm using Asterisk 1.4.26.1
>
> Thanks a lot.
>
>  
>
> This is just a guess, but, I think that if any of the users is using inband
> DTMF and its sip.conf is not enabled to detect inband dtmf, you may have
> this result. 
>
>  
>
> The 'F' options MUST work if all the peers are properly configured,
> otherwise is a bug. I order to asterisk to mute or ignore that DTMF it must
> first properly detect it. Use the /etc/asterisk/logger.conf configuration to
> display detected dtmf and make sure all users dtmf is being detected. 
>
>  
>
> If the dtmf is detected by asterisk and you use the F option in meetme and
> still you hear the dtmf, then is a bug, try to reproduce it with latest 1.4
> version, if you can reproduce it the bug must be filled in
> issues.asterisk.org.
>
>  
>   
On reading the responses to this thread, I think there is a big omission 
that needs to be mentioned. I am a co-worker of the original poster, and 
I need to point out that the issue of the DTMFs is happening on a 
DAHDI-only setup. To elaborate: the Asterisk server (with 
asterisk-1.4.26.1) has a set of ISDN cards dedicated to incoming calls 
that are directed to one of several conference rooms created with 
app_meetme. As far as we know, there are no SIP phones connected to this 
server. All calls come from the public PSTN system.

The problem with the DTMFs is that some (but not all) keys are used by 
our dialplan to implement some custom actions. When the conference 
members press keys that are unused in the dialplan, all of the other 
conference members hear the DTMF sounds. This is undesirable in this 
server, so we are looking for a way (if it exists) to prevent other 
conference members from hearing the DTMF sounds caused by any one 
conference member pressing the numeric keys, while still preserving the 
keypress functionality (switching to other conference rooms, other 
custom actions).

For this particular server, we cannot rely on cooperation from the 
conference members, as this is a public PBX (anyone is and must be 
allowed to dial in). Therefore, asking the conference members to "stop 
pressing keys at random" is not an (enforceable) option for us. The 
scenario we are trying to prevent is one where malicious users start 
pressing random keys for the sake of disturbing the conference and 
annoying other conference users.

I have the suspicion that in this particular setup, what we are asking 
is difficult (if not impossible) to implement, as these DTMFs are 
probably in-band and therefore require signal processing to remove. I 
would be more than happy to be proven wrong on this issue.

-- 
perl -e '$x=2.3;printf("%.0f + %.0f = %.0f\n",$x,$x,$x+$x);'