Yealink SIP-T21 User Manual
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User Guide for the SIP-T21P/SIP-T21 IP Phone
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The valid multicast IP addresses range from 224.0.0.0 to 239.255.255.255.
6. Press the Save soft key to accept the change or the Back soft key to cancel.
Multicast paging key is configurable via web user interface at the path DSSKey->Line
Key.
You can also configure the phone to use a default codec for sending multicast RTP
stream via web interface.
To configure a default codec for multicast paging via web user interface:
1. Click on Features->General Information.
2. Select the desired codec from the pull-down list of Multicast Codec.
The default codec is G722.
3. Click Confirm to accept the change.
Note
To send RTP stream:
1. Press the multicast paging key when the phone is idle.
The phone sends RTP to a preconfigured multicast address (IP: Port). Any phone in
the local network then listens to the RTP on the preconfigured multicast address (IP:
Port). For both sending and receiving of the multicast RTP, there is no SIP signaling
If G722 codec is used for multicast paging, the LCD screen prompts "HD" to indicate that
the phone is providing high definition voice.
Default codec for multicast paging is configurable via web user interface only.