Nortel Networks TP-1610 SIP user manual Mediant 2000 SIP User’s Manual 144 Document # LTRT-72504

Mediant 2000 SIP

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 Low Bit Rate (LBR) coders the quality of the DTMF digits is reduced.

To set this mode:

‘IsDTMFUsed = 0’	(Use Out-of-Band DTMF = No)
‘TxDTMFOption = 0’	(DTMF RFC 2833 Negotiation = Disable)
‘RxDTMFOption = 0’	(Declare RFC 2833 in SDP = No)

‘DTMFTransportType = 2’ (DTMF Transport Type = Transparent DTMF)

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 Mediant 2000 SIP handles the DTMF digits:

Table 8-3: Summary of DTMF Configuration Parameters (continues on pages 144 to 145)

ini File Field Name		Valid Range and Description
[Web Name]
IsDTMFUsed	Use out-of-band signaling to relay DTMF digits.
[Use Out-of-Band DTMF]	0	= Disable, DTMF digits are sent according to DTMFTransportType parameter. (default)
	1	= Enable sending DTMF digits within INFO or NOTIFY messages.
	Note: When out-of-band DTMF transfer is used, DTMFTransportType is automatically
	set to 0 (erase the DTMF digits from the RTP stream).
OutOfBandDTMFFormat	The exact method to send out-of-band DTMF digits
[Out-of-Band DTMF Format]	1	= INFO format (Nortel)
	2	= INFO format (Cisco) - (default)
	3	= NOTIFY format <draft-mahy-sipping-signaled-digits-01.txt>
	Note 1: To use out-of-band DTMF, set “IsDTMFUsed=1”.
	Note 2: When using out-of-band DTMF, the “DTMFTransportType” parameter is
	automatically set to 0, to erase the DTMF digits from RTP path.
TxDTMFOption	0	= No negotiation, DTMF digit is sent according to the parameters
[DTMF RFC 2833	‘DTMFTransportType’ and ‘RFC2833PayloadType’.
Negotiation]	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.

Mediant 2000 SIP User’s Manual 144 Document #: LTRT-72504