Yealink SIP-T2 SERIES Administrator's Manual page 677

If you place a call via web user interface but the trusted IP address has not been
configured, the web user interface prompts ―Call fail‖.
To place a call via web user interface:
1. Click on Directory->Phone Call Info.
2. Select the desired account from the pull-down list of Outgoing Identity.
3. Enter the callee's number in the Dial Number field.
4. Click Dial to dial out the number.
The web user interface prompts ―Call Success‖ and the phone will automatically
dial out the number. You can click Hang Up to end the call.
If it is the first time you place a call via web user interface, the LCD screen will
prompt the message ―Allow remote control?‖. Press OK on the phone to allow
remote control and then the phone will automatically dial out the number.
Note
You can also place an IP direct call via web user interface. The IP phone supports either
IPv4 or IPv6 address.
Server redundancy is often required in VoIP deployments to ensure continuity of phone
service, for events where the server needs to be taken offline for maintenance, the
server fails, or the connection between the IP phone and the server fails.
Two types of redundancy are possible. In some cases, a combination of the two may be
deployed:
Failover: In this mode, the full phone system functionality is preserved by having a

second equivalent capability call server take over from the one that has gone
down/off-line. This mode of operation should be done using the DNS mechanism
from the primary to the secondary server.
Fallback: In this mode, a second less featured call server with SIP capability takes

over call control to provide basic calling capability, but without some advanced
features (for example, shared line, call recording and MWI) offered by the working
server. IP phones support configuration of two servers per SIP registration for
Configuring Advanced Features
655