Yealink SIP-T4X Administrator's Manual page 28

Administrator's Guide for SIP-T4X IP Phones
Power over Ethernet
With the included or a regular Ethernet cable, IP phones can be powered from a
PoE-compliant switch or hub.
To connect the PoE:
1. Connect the Ethernet cable between the Internet port on IP phones and an
available port on the in-line power switch/hub.
Note
If in-line power switch/hub is provided, you don't need to connect the phone to the power
adapter. Make sure the switch/hub is PoE-compliant.
IP phones can also share the network with another network device such as a PC
(personal computer). It is an optional connection.
Important! Do not unplug or remove the power while IP phones are updating firmware
and configurations.
The initialization process of IP phones is responsible for network connectivity and
operation of IP phones in your local network.
Once you connect your IP phone to the network and to an electrical supply, the IP phone
begins its initialization process.
During the initialization process, the following events proceed:
Loading the ROM file
The ROM file resides in the flash memory of IP phones. IP phones come from the factory
with a ROM file preloaded. During initialization, IP phones run a bootstrap loader that
loads and executes the ROM file.
Configuring the VLAN
If IP phones are connected to a switch, the switch notifies IP phones of the VLAN
information defined on the switch (if using LLDP). IP phones can then proceed with the
DHCP request for its network settings (if using DHCP).
12