[Asterisk-Users] inband dtmf on ploycom ip501?

[Eric "ManxPower" Wieling]

Kanuri, Seshu (Company IT) wrote:
> Add the line as under to your sip.conf entry.
> 
> Progressinband=no 
> ;progressinband=never   - is erroneous
>  
> Seshu Kanuri
> 
> -----Original Message-----
> From: asterisk-users-bounces at lists.digium.com
> [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Chris
> Miller
> Sent: Tuesday, November 01, 2005 2:23 PM
> To: Asterisk Users Mailing List - Non-Commercial Discussion
> Subject: Re: [Asterisk-Users] inband dtmf on ploycom ip501?
> 
> Damon Estep wrote:
> 
>>Anyone have any hints on how to get the polycom ip501 to send dtmf 
>>inband, our upstream providers require inband and the native rfc2833 
>>format of the polycom does not work.
> 
> 
> In order for inband to make it beyond Asterisk, you need to disable
> rfc2833 control in the Polycom config file "sip.cfg" (i.e. via ftp
> server).
> 
> tone.dtmf.rfc2833Control="0"
> 
> It appears that although Asterisk recognizes and uses inband dtmf
> internally, rfc2833 is used on the external channel. I noticed this
> behavior when remote IVR systems weren't acknowledging dtmf.

If that's your problem then just increase the DTMF length Asterisk sends.

/path/to/src/zaptel/digits.h

Change:
   #define DEFAULT_DTMF_LENGTH     250 * 8
To:
   #define DEFAULT_DTMF_LENGTH     450 * 8


Changing it to 350 is one of our standard patches to Zaptel that we use 
internally.

This does not solve the problem when you do not control the Asterisk 
server that connects to the PSTN, of course.