Yealink SIP-T2 SERIES Administrator's Manual page 372

Administrator's Guide for SIP-T2 Series/T19(P) E2/T4 Series/CP860 IP Phones
call is actually established. Current implementation supports early media through the
183 message. When the caller receives a 183 message with SDP before the call is
established, a media channel is established. This channel is used to provide the early
media stream for the caller.
180 ring workaround defines whether to deal with the 180 message received after the
183 message. When the caller receives a 183 message, it suppresses any local ringback
tone and begins to play the media received. 180 ring workaround allows IP phones to
resume and play the local ringback tone upon a subsequent 180 message received.
Procedure
180 ring workaround can be configured using the configuration files or locally.
Configuration File
Local
Details of the Configuration Parameter:
phone_setting.is_deal180
Description:
Enables or disables the IP phone to deal with the 180 SIP message received after the
183 SIP message.
0-Disabled
350
<y0000000000xx>.cfg
Web User Interface
Parameter
Configure 180 ring workaround.
Parameter:
phone_setting.is_deal180
Configure 180 ring workaround.
Navigate to:
For
SIP-T48G/T46G/T42G/T41P/T40P/T2
9G/T27P/T23P/T23G/T21(P)
E2/T19(P) E2/CP860:
http://<phoneIPAddress>/servlet
?p=features-general&q=load
For SIP VP-T49G:
http://<phoneIPAddress>/servlet
?m=mod_data&p=features-gen
eral&q=load
Permitted Values
0 or 1
Default
1