User`s manual
SIP User's Manual 8. Telephony Capabilities
Version 5.0 219 December 2006
3. Using NOTIFY messages according to <draft-mahy-sipping-signaled-digits-01.txt>:
In this mode DTMF digits are carried to the remote side using NOTIFY messages.
To enable this mode set:
• ‘RxDTMFOption = 0’ (Declare RFC 2833 in SDP = No)
• ‘TxDTMFOption = 2’ (1
st
to 5
th
DTMF Option = NOTIFY)
Note that in this mode DTMF digits are erased from the audio stream
(DTMFTransportType is automatically set to 0 (DTMF Mute)).
4. Using RFC 2833 relay with Payload type negotiation:
In this mode, DTMF digits are carried to the remote side as part of the RTP stream in
accordance with RFC 2833 standard.
To enable this mode set:
• ‘TxDTMFOption = 4’ (1
st
to 5
th
DTMF Option = RFC 2833)
• ‘RxDTMFOption = 3’ (Declare RFC 2833 in SDP = Yes)
Note that to set the RFC 2833 payload type with a different value (other than its
default, 96) configure the ‘RFC2833PayloadType’ (RFC 2833 Payload Type)
parameter. The gateway negotiates the RFC 2833 payload type using local and
remote SDP and sends packets using the PT from the received SDP. The
gateway expects to receive RFC 2833 packets with the same PT as configured
by the ‘RFC2833PayloadType’ parameter. If the remote side doesn’t include
‘telephony-event’ in its SDP, the gateway sends DTMF digits in transparent mode
(as part of the voice stream).
5. Sending DTMF digits (in RTP packets) as part of the audio stream (DTMF Relay is
disabled):
Note that this method is normally used with G.711 coders; with other LBR coders the
quality of the DTMF digits is reduced.
To ser this mode:
• ‘TxDTMFOption = 0’ (1
st
to 5
th
DTMF Option = Disable)
• ‘RxDTMFOption = 0’ (Declare RFC 2833 in SDP = No)
• ‘DTMFTransportType = 2’ (DTMF Transport Type = Transparent DTMF)
Notes:
• The gateway is always ready to receive DTMF packets over IP, in all
possible transport modes: INFO messages, NOTIFY and RFC 2833
(in proper payload type) or as part of the audio stream.
• To exclude RFC 2833 Telephony event parameter from the
gateway’s SDP, set ‘RxDTMFOption = 0’ in the ini file.
The following parameters affect the way the MediaPack SIP handles the DTMF digits:
TxDTMFOption, RxDTMFOption and RFC2833PayloadType (described in Table 5-7).
MGCPDTMFDetectionPoint, DTMFDigitLength and DTMFInterDigitInterval (Table
5-47).
DTMFVolume and DTMFTransportType (Table 5-42).