3Com VCX V7122 User Manual page 147

'OutofBandDTMFFormat = 1'
'RxDTMFOption = 0'
Note that in this mode DTMF digits are erased from the audio stream (DTMFTransportType
is automatically set to 0).
Using INFO message according to Cisco's style:
In this mode DTMF digits are carried to the remote side within INFO messages.
To enable this mode set:
'Enable DTMF = Yes' (IsDTMFUsed = 1)
'OutofBandDTMFFormat = 2'
'RxDTMFOption = 0'
Note that in this mode DTMF digits are erased from the audio stream (DTMFTransportType
is automatically set to 0).
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:
'Enable DTMF = Yes' (IsDTMFUsed = 1)
'OutofBandDTMFFormat = 3'
'RxDTMFOption = 0'
Note that in this mode DTMF digits are erased from the audio stream (DTMFTransportType
is automatically set to 0).
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:
'Enable DTMF = No' (IsDTMFUsed = 0)
'DTMF RFC 2833 Negotiation = Yes' (TxDTMFOption=4)
'RxDTMFOption = 3'
'DTMFTransportType = 3'
Note that to set the RFC 2833 payload type with a different value (other than its default, 96)
configure the 'RFC2833PayloadType' 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. The RFC 2833 packets are sent even if the remote
side didn't include the send "telephone-event" parameter in its SDP, in which case the
gateway uses the same PT for send and for receive.
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 Low Bit Rate (LBR)
coders the quality of the DTMF digits is reduced.
To set this mode:
'Enable DTMF = No' (IsDTMFUsed = 0)
'DTMF RFC 2833 Negotiation = No' (TxDTMFOption=0)
3Com VCX V7122 SIP VoIP Gateway User Manual 147