[SIPForum-discussion] What is the function of telephone-event?

[Victor Pascual Ávila]

Folks,
is there any interoperability between DTMF modes? If I'm using
RFC2833,  is there other possibility to convert it to SIP Info Method
not using a media-proxy?

Cheers,
Victor Pascual

On Thu, Mar 6, 2008 at 5:18 PM, Andrea Puddu <androjoker at hotmail.com> wrote:
>
> It's clear now. Thanks everybody.
>
> Andrea
>
>
>
> ________________________________
> From: mh at markholloway.com
> To: androjoker at hotmail.com; steve.langstaff at citel.com;
> discussion at sipforum.org
>
> Subject: RE: [SIPForum-discussion] What is the function of telephone-event?
> Date: Thu, 6 Mar 2008 08:08:07 -0700
>
>
>
>
>
>
> G729 does not support inband DTMF because the codec compresses the audio.
> You must use out of band.  Therefore, telephone-event is used to tell the
> other endpoint how it should receive DTMF tones.  If you are using G711 you
> should be able to support inband.  If you are using a compressed codec you
> should consider using out of band.  This can be RFC 2833 or SIP Info Method.
> Regardless, not supporting telephone-event reflects a poor SIP
> implementation in my opinion.
>
>
>
>
>
>
>
> From: discussion-bounces at sipforum.org
> [mailto:discussion-bounces at sipforum.org] On Behalf Of Andrea Puddu
>  Sent: Thursday, March 06, 2008 7:09 AM
>  To: Steve Langstaff; discussion at sipforum.org
>  Subject: Re: [SIPForum-discussion] What is the function of telephone-event?
>
>
>
> Thanks Steve.
>
>  Why did you talk about low bit-rate codec? I understood the matter about
> dtfm out of band, but it is not clear to me why it should impact low bit
> rate codec (e.g. g729).
>
>  Thanks,
>
>  Andrea
>
>
>
>
>  ________________________________
>
>
> Subject: RE: [SIPForum-discussion] What is the function of telephone-event?
>  Date: Thu, 6 Mar 2008 05:01:34 -0800
>  From: steve.langstaff at citel.com
>  To: androjoker at hotmail.com; discussion at sipforum.org
>
> "telephone-event" is a method for passing e.g. DTMF signalling in an RTP
> stream.
>
>
>
> The "101" (or any payload type in the range 96-127) refers to a dynamic
> payload type.
>
>
>
> So a stream that negotiates to use "101 telephone-event" may e.g. pass
> keypresses
>
> using RTP payload type 101 rather than "in-band".
>
>
>
> The risks you face in removing telephone event support are that if you are
> using a
>
> low bitrate codec such as G.729, or you are using equipment that does not
> expect
>
> to see DTMF "in-band" then users may lose the ability to control e.g. IVR
> equipment.
>
>
>
>  ________________________________
>
>
> From: discussion-bounces at sipforum.org
> [mailto:discussion-bounces at sipforum.org] On Behalf Of Andrea Puddu
>  Sent: 06 March 2008 12:15
>  To: discussion at sipforum.org
>  Subject: [SIPForum-discussion] What is the function of telephone-event?
>
> Hello guys,
>
>  as the network here does not completely support "telephone event" in SDP
> they asked me to set up phones to not include "telephone event".
>  I have looked at some RFCs .... but I couldn't understand what the
> telephone events are useful to.
>
>  Do you see any risk to remove the telephone event, in particular the 101
> telephone event?
>
>  thanks 1000.
>
>  Andrea
>
>
>  ________________________________
>
>
> MSN Video Interviste, concerti, news e videoclip! Solo su MSN Video!
>
>
>  ________________________________
>
>
> MSN Video Interviste, concerti, news e videoclip! Solo su MSN Video!
>
>
> ________________________________
> MSN Video Interviste, concerti, news e videoclip! Solo su MSN Video!
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>



-- 
Victor Pascual Ávila
Research Engineer
Tel.  +34 93 542 2906
Fax. +34 93 542 2517

Research Group on Network Technologies and Strategies (NeTS)
Universitat Pompeu Fabra (UPF)
Pg. de Circumval·lació, 8
Office 358
08003 Barcelona (Spain)
http://nets.upf.edu/