[Freeswitch-users] Codec Negotiation: Codec telephone-event:101:8000:20

[Mark Campbell-Smith]

Thanks guys for your response.  I'll have a read through the links sent to me.

On the INVITE my FS box sends to Phonzo (the SIP provider) the codecs
it supports are G726-32, PCMU, PCMA.

 v=0
 o=FreeSWITCH 1262742568 1262742569 IN IP4 xxx.xxx.xxx.xx
 s=FreeSWITCH
 c=IN IP4 xxx.xxx.xxx.xxx
 t=0 0
 m=audio 31566 RTP/AVP 2 0 8 101 13
 a=rtpmap:2 G726-32/8000
 a=rtpmap:0 PCMU/8000
 a=rtpmap:8 PCMA/8000
 a=rtpmap:101 telephone-event/8000
 a=fmtp:101 0-16
 a=rtpmap:13 CN/8000
 a=ptime:20

However, Phonzo responds with the following in the Session Progress message:

  v=0
  o=Sippy 158698636 1 IN IP4 80.232.37.178
  s=-
  t=0 0
  m=audio 61812 RTP/AVP 2 101 13
  c=IN IP4 213.50.91.3
  a=rtpmap:101 telephone-event/8000
  a=fmtp:101 0-15

Does that make sense?   The codec rtpmap only included DTMF ...

On Thu, Jan 7, 2010 at 2:04 AM, Brian West <brian at freeswitch.org> wrote:
> w00t! :)
> /b
> On Jan 6, 2010, at 1:29 AM, Arsen Chaloyan wrote:
>
> The following section in RFC3551 states the same
> http://tools.ietf.org/html/rfc3551#section-4.5.4
>
>
>    The encodings of G.726 are here denoted as G726-40, G726-32, G726-24,
>    and G726-16.  Prior to 1990, G721 described the 32 kbit/s ADPCM
>    encoding, and G723 described the 40, 32, and 16 kbit/s encodings.
>    Thus, G726-32 designates the same algorithm as G721 in RFC 1890.
>
>
> ________________________________
> From: Brian West <brian at freeswitch.org>
> To: freeswitch-users at lists.freeswitch.org
> Sent: Wed, January 6, 2010 9:50:46 AM
> Subject: Re: [Freeswitch-users] Codec Negotiation: Codec
> telephone-event:101:8000:20
>
> They are in fact one in the same please see ITU.
>
> /b
>
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