AASTRA 6700i series, 9143, 9480i, 9480i CT SIP Administrator Guide EN - Manual (Page 674)

41-001343-01 Rev 03, Release 3.2.2 6-47
“Early-Only” Parameter in Replaces Header RFC3891
The phones support the “early-only” parameter in the “Replaces” header according to RFC3891.
When the phone receives a Replaces header with the early-only parameter, it replaces the existing
dialog if the call is still in the early state. If the call has been answered, then the Replaces request
is rejected.
Switching Between Early Media and Local Ringing
Previous to release 2.6, the phone generated a local ring tone when receiving a 180 response unless
early media was being played, regardless of SDP. The local ring tone stopped when the first RTP
packet was received in the early session. The local ring tone did not resume when it received
subsequent 180 responses, even though early media was not being received.
In Release 2.6 and up, the phone supports switching between early media and local ring tone.
Upon receiving a 180 response, the phone now generates a local ring tone unless it is receiving an
early media flow. If the phone receives any subsequent 180 responses, it regenerates the local ring
tone unless it is receiving early media flow.
Enable Microphone During Early Media
The phones now allow Administrators to enable or disable the microphone during early media by
configuring the “sip early media mute mic” parameter. Early media indicates the period when a
call has not fully established (i.e. the far end has not answered the call). By enabling this
parameter, Administrators can mute the microphone during early media to prevent the far end from
listening into the call prior to answering it.
Enabling/Disabling “Microphone During Early Media”
Use the following procedure to enable/disable “microphone during early media:
“Call-Info” Header to 200ok Responses for Shared Call Appearance (SCA) Lines
In earlier versions of the IP phone software releases, a "Call-Info" header was only added to the
requests generated by the phone for Shared Call Appearance (SCA) lines. A “Call-Info” header ia
now also included in the 200ok response to an INVITE, RE-INVITE, and UPDATE messages for
SCA lines. No configuration is required for this feature.
Note: This feature is not supported in outgoing requests.
Configuration Files
For the specific parameter you can set in the configuration files, see Appendix A, the section, “Enable
Microphone During Early Media” on page A-186.