Yealink T21PE2 User Manual

Administrator’s Guide for SIP-T2 Series/T4 Series/T5 Series/CP920 IP Phones
356
Early Media
The early media refers to the media (for example, audio and video) played to the caller before a SIP call is actually estab-
lished.
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 also configure 180 ring workaround which 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.
Topic
Early Media Configuration
Early Media Configuration
The following table lists the parameters you can use to configure the early media.
Parameter
phone_setting.early_media.rtp_sniffer.timeout
[1]
<y0000000000xx>.cfg
Description
It configures the time to wait for the IP phone to play the local ringback tone when the early media can-
not be played.
Permitted
Values
-1-Do not play the local ringback tone
0-Play the local ringback tone immediately
1-100-Wait for a specified time to play the local ringback tone
Default 1
Parameter phone_setting.is_deal180 <y0000000000xx>.cfg
Description It enables or disables the IP phone to deal with the 180 SIP message received after the 183 SIP message.
Permitted
Values
0-Disabled
1-Enabled, the IP phone will resume and play the local ringback tone upon a subsequent 180 message
received.
Default 1
Web UI Features->General Information->180 Ring Workaround
Parameter phone_setting.change_183_to_180 <y0000000000xx>.cfg
Description It enables or disables the IP phone to handle the received second 183 message as the 180 message.
Permitted
Values
0-Disabled
1-Enabled, the IP phone will play the early media first and play the local ringback tone when receiving the
second 183 message.
Default 0
[1]
If you change this parameter, the IP phone will reboot to make the change take effect.

Yealink T21PE2 Specifications

General

Brand	Yealink
Model	T21PE2
Category	IP Phone
Language	English