connect to the "service" port on the S8300 processor with a LAN "crossover" cable, set your PC's ethernet port to 192.11.13.6/30, ping "192.11.13.6", when you get a reply, "telnet 192.11.13.6", then login with any login/password you have... at this point you can also open a web browser to 192.11.13.6, and run "configure server" and reset your IP address this way.
Mitch
AVAYA Certified Expert