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

[Andrea Puddu]

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! 

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