[Spce-user] Loss of DTMF function

William Fulton wfulton at thirdhatch.com
Tue Nov 3 11:10:02 EST 2015


It seems that most of our carriers only support rfc2833 for dtmf mode.
I will change this setting in the config.yml and see if it helps.  I do
find it curious that is has just started happening since we have been
stable for many months with no issues.  Is there a recommended interval
for rebooting the server to head off problems like this?

Thank you,

-----Original Message-----
From: Spce-user [mailto:spce-user-bounces at lists.sipwise.com] On Behalf
Of Daniel Grotti
Sent: Tuesday, November 03, 2015 7:56 AM
To: spce-user at lists.sipwise.com
Subject: Re: [Spce-user] Loss of DTMF function

end-to-end DTMF just pass through NGCP, so cannot be an issue in NGCP.
Unless the devices in not sending DTMF using INFO message.
In that case you should enable:

    allow_info_method: 'no'

in config.yml.

NGCP handle DTMF mainly when you call Aasterisk (VM), and DTMF setting
can be changed or tuned in config.yml:

    bindport: 5070
    dtmfmode: rfc2833

values are:

* inband: The device that you press the key on will generate the DTMF
tones. - If the codec is not ulaw or alaw then the DTMF tones will be
distorted by the audio compression and will not be recognised. If the
phone is set for RFC2833 and asterisk is set for inband then you may not
hear anything.

* rfc2833: http://www.ietf.org/rfc/rfc2833.txt

* info: See SIP method info and SIP info DTMF or

* auto: Asterisk will use rfc2833 for DTMF relay by default but will
switch to inband DTMF tones if the remote side does not indicate support
of rfc2833 in SDP. This feature was added on Sep 6, 2005 and is not
available in Asterisk 1.0.x.

Daniel Grotti
VoIP Engineer

Sipwise GmbH
Europaring F15 | 2345 Brunn am Gebirge, Austria | www.sipwise.com

On 11/02/2015 07:32 PM, William Fulton wrote:
> Hi,
> We are on version 3.7 of the software.  We have been stable for many 
> months now, but just recently have discovered an issue with DTMF.  
> Some of our endpoints use IVR to route calls, but just recently we 
> noticed that they were not functioning properly.  We performed 
> troubleshooting tasks at the endpoints and traced the problem to the
SPCE box.
> Performing the "ngcpcfg apply" command seems to restore DTMF functions

> to the endpoints for a short time, but already today I have had to 
> restart the services twice to fix the issue.  Is there an underlying 
> vulnerability or bug?  Has anyone else had this issue?
> Thanks,
> Bill
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