Yealink SIP-T48G Administrator's Manual page 262

Microsoft Lync Edition Administrator's Guide for SIP-T2_Series and T4_Series IP Phones
IP phones use the PoE preferentially.
Auto provisioning refers to the update of IP phones, including update on configuration
parameters, local phone book, firmware and so on. You can use auto provisioning on a
single phone, but it makes more sense in mass deployment.
Plug and Play (PnP) is a method for IP phones to acquire the provisioning server address.
With PnP enabled, the IP phone broadcasts the PnP SUBSCRIBE message to obtain a
provisioning server address during startup. Any SIP server recognizing the message will
respond with the preconfigured provisioning server address, so the IP phone will be
able to download the CFG files from the provisioning server. PnP depends on support
from a SIP server.
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Do one of the following:
Ensure that the configuration is set correctly.

Reboot the phone. Some configurations require a reboot to take effect.

Ensure that the configuration is applicable to the IP phone model.

The configuration may depend on support from a server.

Do one of the following:
Reset another available IP address for the IP phone.

Check network configuration via phone user interface at the path

Menu->Settings->Advanced Settings->Network->WAN Port->IPv4 (or IPv6). If the
Static IP is selected, select DHCP instead.
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