A simple memo (in english!) to explain the configuration of DHCP option 150:
Cisco phone use TFTP to download their configuration. To determine the address of the TFTP server, the phone (when the phone starts) sends a DHCP request with option 150 (DHCP 150 provide address of the TFTP server). Below, you will find a simple way to configure this option on a Cisco switch:
ip dhcp pool DHCPPool
network 192.162.1.0 255.255.255.0
option 150 ip 192.168.1.200
default-router 192.168.1.1