[SIPForum-discussion] Does every Voip phone use SIP INFO to send DTMF?

Paul Kyzivat pkyzivat at alum.mit.edu
Tue Aug 25 16:16:05 UTC 2015

On 8/24/15 2:26 PM, Rodrigo Pimenta Carvalho wrote:
> Hi.
> In my office I have a Voip phone. During a call with such device,
> whether I dial 200 for example, the phone will generate a SIP INFO
> message containing the value 200. Good!
> Does every Voip phone send DTMF values as SIP INFO messages? Is it in
> general  a kind of standard in the telecommunications? Or is it a matter
> of some device configuration?

No, this is not standard. Is this *instead* of sending an INVITE? Or in 

It sounds like a proprietary mechanism for turning sip phone into a dumb 
endpoint so that the server can handle all the logic.

What voip server system and handset do you have?


> Any hint will be very helpful!
> Best regards.
> Inatel Competence Center
> Software
> Ph: +55 35 3471 9200 RAMAL 979
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