The O3-DIN-ACCESS module is part of the O3 system, a BACnet® platform developed to integrate all aspects of room control into a single controller. When connected to an O3-DIN controller on the O3 system, the O3-DIN‑ACCESS module provides remote, fully programmable, door access control and expanded I/O capabilities. Up to 24 access modules can be connected to an O3-DIN-CPU controller with the addition of 5 O3-DIN power injector modules Up to 4 access modules can be connected to an O3-DIN-SRC controller.