HOWTO Get Polycom IP 501 To Download Configuration From TFTP
Getting configuration files from TFTP depends on which DHCP server you are using. Regarding Cisco routers, you have to add this option 'option 66 ascii "xxx.xxx.xxx.xxx"' where xxx's are the IP address.
ISC's DHCP server requires a bit of different format 'option tftp-server-name "XXX.XXX.XXX.XXX";