Various locks and alarms protect the installation from unauthorized access. A Technology check (DC 20) overcomes these systems. Each additional feature increases the DC by +5, to a maximum of DC 40. The security system may be tied into a defense system (if the installation is equipped with that feature), so triggering an alarm activates the defense system to disable or restrain the intruder(s).
D20 Hero SRD Installations Article- http://www.d20herosrd.com/7-gadgets-gear/installations