SIP User's Manual 490 Document #: LTRT-12801
MP-500 MSBG
9.5 Configuring DTMF Transport Types
You can control the way DTMF digits are transported over the IP network to the remote
endpoint, by using one of the following modes:
îš„ Using INFO message according to Nortel IETF draft: DTMF digits are carried to the
remote side in INFO messages. To enable this mode, define the following:
• RxDTMFOption = 0 (ini file); 'Declare RFC 2833 in SDP' field = 'No'
• TxDTMFOption = 1 (ini file); '1
st
to 5
th
Tx DTMF Option' field = 'INFO (Nortel)'
Note that in this mode, DTMF digits are erased from the audio stream
[DTMFTransportType is automatically set to 0 ('DTMF Transport Type' field = 'DTMF
Mute' -- Web interface)].
 Using INFO message according to Cisco’s mode: DTMF digits are carried to the
remote side in INFO messages. To enable this mode, define the following:
• RxDTMFOption = 0 (ini file); 'Declare RFC 2833 in SDP' field = 'No'
• TxDTMFOption = 3 (ini file); '1
st
to 5
th
Tx DTMF Option' field = 'INFO (Cisco)'
Note that in this mode, DTMF digits are erased from the audio stream
(DTMFTransportType is automatically set to 0 ('DTMF Transport Type' field = 'DTMF
Mute' -- Web interface)].
îš„ Using NOTIFY messages according to <draft-mahy-sipping-signaled-digits-
01.txt>: DTMF digits are carried to the remote side using NOTIFY messages. To
enable this mode, define the following:
• RxDTMFOption = 0 (ini file); 'Declare RFC 2833 in SDP' field = 'No'
• TxDTMFOption = 2 (ini file); '1
st
to 5
th
Tx DTMF Option' field = 'NOTIFY'
Note that in this mode, DTMF digits are erased from the audio stream
(DTMFTransportType is automatically set to 0 ('DTMF Transport Type' field = 'DTMF
Mute' -- Web interface)].
îš„ Using RFC 2833 relay with Payload type negotiation: DTMF digits are carried to
the remote side as part of the RTP stream in accordance with RFC 2833 standard. To
enable this mode, define the following:
• RxDTMFOption = 3 (ini file); 'Declare RFC 2833 in SDP' field = 'Yes'
• TxDTMFOption = 4 (ini file); '1
st
to 5
th
Tx DTMF Option' field = 'RFC 2833'
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 device negotiates the RFC 2833 payload type using local and remote
SDP and sends packets using the payload type from the received SDP. The device
expects to receive RFC 2833 packets with the same payload type as configured by the
RFC2833PayloadType parameter. If the remote side doesn’t include ‘telephony-event’
in its SDP, the device sends DTMF digits in transparent mode (as part of the voice
stream).
îš„ Sending DTMF digits (in RTP packets) as part of the audio stream (DTMF Relay
is disabled): This method is typically used with G.711 coders; with other low-bit rate
(LBR) coders, the quality of the DTMF digits is reduced. To enable this mode, define
the following:
• RxDTMFOption = 0 (ini file); 'Declare RFC 2833 in SDP' field = 'No'
• TxDTMFOption = 0 (ini file); '1
st
to 5
th
Tx DTMF Option' field = 'Disable'
• DTMFTransportType = 2 (DTMF Transport Type = Transparent DTMF)
To Next Page
Loading...
Need help?
General
