Additional Expander Module with 32 zones on BUS for LightSYS and ProSYS/ProSYS Plus RISCO control panels. Grade 3 Certified. Each BUS Zone Expander creates a separate BUS branch. Each Expander can be configured to support 8, 16, 24 or 32 detectors on the BUS. The BUS branch increases the overall security of the system in the event that a certain BUS detector is sabotaged. It has the function of isolator and concentrator. Risco BUS detectors allow remote adjustment.