Yealink SIP-T21 - Manual (Page 116)

User Guide for the SIP-T21P/SIP-T21 IP Phone
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To configure multicast listening addresses via web user interface:
1. Click on Directory->MulticastIP.
2. Select the desired value from the pull-down list of Paging Barge.
3. Select the desired value from the pull-down list of Paging Priority Active.
4. Enter the multicast IP address(es) and port number (e.g., 224.5.6.20:10008) which
the phone listens for incoming RTP multicast in the Listening Address field.
The valid multicast IP addresses range from 224.0.0.0 to 239.255.255.255.
5. Enter the label in the Label field.
Label will appear on the LCD screen when receiving the RTP multicast.
6. Click Confirm to accept the change.
Note
Music on hold (MoH) is the business practice of playing recorded music to fill the silence
that would be heard by the party placed on hold. To use this feature, you should specify
a SIP URI pointing to a MoH server account. When a call is placed on hold, the phone
will send a SIP INVITE message to the MoH server account. The MoH server account
automatically answers to the SIP INVITE messages and immediately plays audio from
some source located anywhere (LAN, Internet) to the held party. Contact your system
administrator for the SIP URI.
The priorities of listening addresses are predefined: 1 with the highest priority, 10 with the
lowest.
Both the multicast paging sender and the receiver play a warning tone when pressing
the multicast paging key.
Multicast listening addresses is configurable via web user interface only.