MP-1xx SIP User’s Manual 8. Gateway Capabilities Description
Version 4.4 151 March 2005
‘DTMF RFC 2833 Negotiation = No’ (TxDTMFOption=0)
‘RxDTMFOption = 0’
‘DTMFTransportType = 2’
Note 1: 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.
Note 2: 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 MP-1xx SIP handles the DTMF digits:
Table
8-1: Summary of DTMF configuration Parameters (continues on pages 151 to 152)
ini File Field Name
[Web Name]
Valid Range and Description
IsDTMFUsed
[Use Out-of-Band DTMF]
Use out-of-band signaling to relay DTMF digits.
No [0] = DTMF digits are sent inband (default).
Yes [1] = DTMF digits are sent out-of-band according to the parameter ‘Out-of-band
DTMF format’.
Note: When out-of-band DTMF transfer is used (Enable DTMF = Yes), the parameter
‘DTMF Transport Type’ is automatically set to 0 (erase the DTMF digits from the RTP
stream).
OutOfBandDTMFFormat
[Out-of-Band DTMF Format]
The exact method to send out-of-band DTMF digits.
Info (Nortel) [1] = Sends DTMF digits according with "IETF draft-choudhuri-sip-info-
digit-00".
Info (Cisco) [2] = Sends DTMF digits according with Cisco format (default).
Notify (3Com) [3] = NOTIFY format <draft-mahy-sipping-signaled-digits-01.txt>.
Note 1: To use out-of-band DTMF, set ‘Enable DTMF = yes’ (‘IsDTMFUsed=1’).
Note 2: When using out-of-band DTMF, the “DTMFTransportType” parameter is
automatically set to 0, to erase the DTMF digits from the RTP stream.
TxDTMFOption
[DTMF RFC 2833
Negotiation]
No [0] = No negotiation, DTMF digit is sent according to the parameters ‘DTMF
Transport Type’ and ‘RFC2833PayloadType’.
Yes [4] = Enable RFC 2833 payload type (PT) negotiation
Note 1: This parameter is applicable only if “IsDTMFUsed=0” (out-of-band DTMF is not
used).
Note 2: If enabled, the gateway:
• Negotiates RFC 2833 payload type using local and remote SDPs.
• Sends DTMF packets using RFC 2833 PT according to the PT in the received SDP.
• Expects to receive RFC 2833 packets with the same PT as configured by the
“RFC2833PayloadType” parameter.
Note 3: If the remote party doesn’t include the RFC 2833 DTMF relay payload type in the
SDP, the gateway uses the same PT for send and for receive.
Note 4: If TxDTMFOption is set to 0, the RFC 2833 payload type is set according to the
parameter ‘RFC2833PayloadType’ for both transmit and receive.
RxDTMFOption
Defines the supported Receive DTMF negotiation method.
No [0] = Don’t declare RFC 2833 Telephony-event parameter in SDP
Yes [3] = Declare RFC 2833 Telephony-event parameter in SDP (default)
The MP-1xx is designed to always be receptive to RFC 2833 DTMF relay packets.
Therefore, it is always correct to include the “Telephony-event” parameter as a default in
the SDP. However some gateways use the absence of the “telephony-event” from the
SDP to decide to send DTMF digits inband using G.711 coder, if this is the case you can
set “RxDTMFOption=0”.
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