The battery you found is the cmos battery that holds programming in loss of power. The reset button restores to factory defalts when following proceedures in the manual. If the system has sat for a year without power it probably has already returned to default but resetting it would be a good idea. To use slt's on the switch it needs to be programmed as it it is not on at default, (program 610). If you're comfortable with programming, use the manuals link above and get a manual for this system.

Kerry

[Linked Image from commsmith.com]