Re: [codec] #5: Mention DTMF in requirements

[Marc Petit-Huguenin <[e-mail]>]

On 03/28/2010 11:00 AM, stephen botzko wrote:
> I would agree with this if I saw reasonable evidence that a
> preponderance of gateways and sending systems provide the signaling in
> these RFCs.
> 
> Since I am not sure that this is the case, I am unconvinced that we can
> totally remove the requirement.
> 
> I'd also say that an encoder that detects the DTMF tones and outputs the
> RFC 4733/34 events would fully meet the requirement.

As former CTO of a VoIP provider, I never saw a PSTN provider not supporting at
least RFC 2833 (even if one of them did not declare it in its SDP)

Perhaps the question can be asked at the next SIPit event.

> 
> Stephen Botzko
> 
> On Sun, Mar 28, 2010 at 11:36 AM, Marc Petit-Huguenin <[e-mail]
> <mailto:[e-mail]>> wrote:
> 
>     I disagree with the "SHOULD".  RFC 4733 and RFC 4734 takes care of
>     DTMF and much
>     more, so this must be an explicit non-goal.  This is an *Internet*
>     codec that we
>     are talking about so it should reuse as much as possible of the existing
>     Internet framework.
> 
>     And BTW, RFC 473[34] is not out of band, it's codec switching.  RFC
>     47[34] is an
>     audio codec, simply very good at compressing a very specific set of
>     frequencies/phases, and replacing everything else by silence.  RFC
>     4730 and RFC
>     2676 are out of band.
> 
>     On 03/26/2010 03:37 PM, Michael Knappe wrote:
>     >  I would agree with 'should'. Lot's of dtmf out there still, but also
>     > out of band options (rfc 2833 / 4733) that make in-band carriage
>     less a
>     > concern for SIP telephony applications.
>     >
>     > Mik
>     >
>     > *From*: [e-mail] <mailto:[e-mail]>
>     <[e-mail] <mailto:[e-mail]>>
>     > *To*: Christian Hoene <[e-mail]
>     <mailto:[e-mail]>>
>     > *Cc*: [e-mail] <mailto:[e-mail]> <[e-mail]
>     <mailto:[e-mail]>>
>     > *Sent*: Fri Mar 26 18:10:31 2010
>     > *Subject*: Re: [codec] #5: Mention DTMF in requirements
>     >
>     > Perhaps analog DTMF carriage is a SHOULD?
>     >
>     > I agree that out-of-band is preferable, however, there still are
>     > scenarios where coded DTMF tones will be sent.  It would be nice
>     (though
>     > IMHO not essential) for this carriage to work.
>     >
>     > Stephen Botzko
>     >
>     > On Fri, Mar 26, 2010 at 3:04 PM, Christian Hoene
>     <[e-mail] <mailto:[e-mail]>
>     > <mailto:[e-mail] <mailto:[e-mail]>>>
>     wrote:
>     >
>     >     Hi,
>     >
>     >     > If the point of this issue to allow this codec to be used to
>     >     successfully
>     >     > transit an IP network between two TDM networks,
>     >
>     >     which is not the primary use-case.
>     >
>     >     > I'd suggest that out-of-
>     >     > band tone transport is far preferable to trying to ensure
>     that the
>     >     codec
>     >     > will carry the tones adequately to allow them to be detected
>     after
>     >     > regeneration.
>     >
>     >     I totally agree. Out-of-band is much better than inband.
>     >
>     >     Sorry for my radical view but I believe that analog DTMF is an old
>     >     and obsolete technology not worth considering anymore.
>     >
>     >     Christian
> 
> 
>     --
>     Marc Petit-Huguenin
>     Personal email: [e-mail] <mailto:[e-mail]>
>     Professional email: [e-mail] <mailto:[e-mail]>
>     Blog: http://blog.marc.petit-huguenin.org
> 
> 


-- 
Marc Petit-Huguenin
Personal email: [e-mail]
Professional email: [e-mail]
Blog: http://blog.marc.petit-huguenin.org