180 Ring Workaround - Yealink SIP-T2 Series Administrator's Manual

Administrator's Guide for SIP-T2 Series/T19(P) E2/T4 Series/T5 Series IP Phones
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.
You can configure the IP phone to play the local ringback tone when receiving the 183 message
but do not receive the RTP stream for the early media.
Procedure
Early media can be configured using the configuration file.
Central Provisioning
(Configuration File)
Details of the Configuration Parameter:
phone_setting.early_media.rtp_sniffer.timeout
Description:
Configures the time to wait for the IP phone to play the local ringback tone when the early
media cannot be played.
-1-Do not play the local ringback tone
0-Play the local ringback tone immediately
1-100-Wait for specified time to play the local ringback tone
Web User Interface:
None
Phone User Interface:
None

180 Ring Workaround

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.
382
<y0000000000xx>.cfg
Parameter
Configures the time to wait for the
IP phone to play the local ringback
tone when the early media cannot
be played.
Parameter:
phone_setting.early_media.rtp_sniffe
r.timeout
Permitted Values
-1, 0 or integer
from 1 to 100
Default
1