Here' from the Trillium Panther 612 manual Page D-5. Take a deep breath and:

1. Connect the KSU power cord to the surge
protector(It assumes you have one)at the AC
power outlet. The recessed STATUS indicator
goes ON --with a slight flicker--indicating
that the KSU is operative.
2. Set KSU switch 4 BATTERY to ON Use a paper
clip or small screw driver to set dip
switches. (This is the battery Paul144 talks
about.)
3. Set KSU switch 1 PROGRAM to ON
4. Push recessed RESET pushbutton once.
5. Set KSU switch 1 PROGRAM to OFF
6. Push recessed RESET button again. System is
set at the factory default settings.
7. At station 10 press the intercom key.

If all that hoo-hah doesn't make it come back to life--say good-bye and Press the INSTALLERS link for help in your area and/or the EQUIPMENT link at the top of this page for a newer system. Good Luck.