Paul Witty wrote:
> Peter Saint-Andre wrote:
>> Paul Witty wrote:
>>
>>> Peter Saint-Andre wrote:
>>>
>>>>> I already have support for
>>>>> in-band DTMF, and, once I've written the stuff to negotiate it, will
>>>>> support RFC 4733 DTMF in the content channel. I'll also implement
>>>>> DTMF
>>>>> in the signalling channel.
>>>>>
>>>> I see two options:
>>>>
>>>> 1. DTMF over XMPP (XEP-0181) ("in-band/signalling")
>>>> 2. DTMF over RTP (RFC 4733) ("out-of-band/media")
>>>>
>>>> Do you see a third option?
>>>>
>>>>
>>> DTMF actually as tones in the audio. Old-fashioned, but valid enough
>>> for G.711, and probably some other codecs as well. Sometimes needed if
>>> going to a SIP to POTS gateway, and not a bad fallback if the far end
>>> doesn't offer support for XEP-0181 or RFC 4733.
>>>
>>
>> Ah, OK, I got confused by terminology. Typically people call the
>> "signalling channel" something like SIP or XMPP (where you negotiate the
>> media session) and the "media channel" something like RTP (the transport
>> for the media). You're talking about sending DTMF as tones in the media
>> itself. Yes, that's old-fashioned, but it probably gets the job done. :)
>>
>>
> I'd consider DTMF tones in the audio to be the only in-band method, with
> RFC 4733 being out-of-band as it is the same channel but different band
> as the media, and XEP-0181 being out-of-band as it is in a different
> channel to the media. I may have a slightly video-conferencing view of
> the world though.
>
> For a bit of a laugh, I've also implemented DTMF through chat messages
> (as well as a very basic chat-based UI to connect to pre-defined
> destinations through the gateway), in order to let released versions of
> Google Talk send messages.
:)
Beyond DTMF, I still think there are very interesting possibilities to
use data forms (XEP-0004) for more structured interaction. Why go
through an IVR menu ("press 1 if you have billing questions" etc.) when
you can send a little form down to the end user and have them click a
few checkboxes?
Peter
--
Peter Saint-Andre
https://stpeter.im/
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