MAPNET II zone adapter modules (ZAMs) provide an addressable interface between conventional zone devices and the host fire alarm control panel. Monitor ZAMs provide status monitoring and supervision of an initiating device circuit (IDC) zone and are used for circuits with non-addressable detectors and for other contact closures such as waterflow and tamper switches or non-addressable manual stations. Different models of Monitor ZAMs are available for two-wire IDCs Class B, or Class A, and for four-wire IDCs with Class B IDC input. Each type required a separate 24 VDC input power from a listed fire alarm power supply. Signal ZAMs supervise and operate 24 VDC notification appliances, speakers, and telephone circuits. Output capacity is up to 2 A @ 24 VDC, or 50 W of 25 VRMS speakers, or up to three simultaneously activated firefighter phones. The signal ZAM is available for either Style Y/Class B or Style Z/Class A operation for notification appliance circuits.