Subject: DTMF detection

From: Yu Zhu <[email-masked]>
Date: Tue, 28 Mar 2000 12:04:30 -0600

Hi there,

The MG shall support detecting and passing DTMF signals to the peer gateway. The
MG can use various methods in order to transport DTMF depending on its
configuration and instructions by the MGC.
The three different types of mechanisms for transport of DTMF are :
1). To the MGC through the standard MEGACO DTMF package
2)  In-band in the RTP stream and
3) Out-of-band through a special payload type in the RTP stream (per the
Internet-draft "RTP Payload for DTMF Digits, Telephony Tones and Telephony
Signals")

In case of sending the DTMF trough the MGC and also when sending it with special
RTP payloads as defined in the latest IETF draft , Should the DTMF be extracted
from the media stream and replaced with comfort noise ? If someone chooses to
use the special RTP packets and extracts DTMF out of media stream, how is it
determined that the other end supports the same mechanism ?

Regards,
-- Yu Zhu