Yealink SIP-T2xP Administrator's Manual page 359

Parameter-
account.X.dtmf.type
Description
Format
Default Value
Range
Example
Configuration File
<MAC>.cfg
Configures the DTMF type for account X.
If it is set to 0 (INBAND), DTMF digits are
transmitted in the voice band.
If it is set to 1 (RFC 2833), DTMF digits are
transmitted by RTP Events compliant to RFC
2833.
If it is set to 2 (SIP INFO), DTMF digits are
transmitted by the SIP INFO messages.
If it is set to 3 (AUTO or SIP INFO), the IP
phone negotiates with the other end to use
INBAND or RFC 2833, if there is no
negotiation, using SIP INFO by default.
X ranges from 1 to 6.
Integer
1
Valid values are:
0-INBAND
1-RFC 2833
2-SIP INFO
3-AUTO or SIP INFO
account.1.dtmf.type = 1
Appendix
343