in their short forms to reduce size. By default, the option is not
enabled and SIP headers in outgoing messages will be encoded in
their full names. (See SIP protocol standard, IETF RFC 3261.)
DTMF Signaling
Method
Select the signaling method for transmitting DTFM tones, either via
RTP (RFC2833) or SIP INFO messages. The default is RTP.
Media on-hold
method
The Media on hold method setting allows switching the Media on
Hold behavior between the different RFC definitions.
“M line only (RFC3264)” implements the functionality according to
RFC3264. In the INVITE message SDP body, the attribute
“a=sendonly” is set to a designated media stream to put media on-
hold.
“M and C line (RFC2543)” implements the functionality according to
RFC2543. In the INVITE message SDP body, the connection line ip
is set to “0.0.0.0” (e.g. “c= IN IP4 0.0.0.0”), and the attribute
“a=inactive” is added.
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