On 1/31/2011 6:06 PM, Mikko Lehto wrote:
> I fail to understand why DTMF delivery methods in signaling path are not as
> stabilized as RFC 2833/4733 is.
> There are many use cases where nice features can be enabled with events
> while dedicated event detector is not feasible in media path.
History.
Very early on there were proprietary INFO-based DTMF methods.
For fairly good reasons, those techniques were found wanting.
Rather than do another INFO-based mechanism, KPML was defined. But it
has not never gotten traction. Meanwhile other mechanisms have been
deployed. Now its to the Tower-of-Babel stage, but any new proposal just
makes it worse.
A lot of Cisco gear supports at least three mechanisms, (maybe more)
with transcoding between them. :-(
Thanks,
Paul
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