Four-door access control kit for the RACS 5 v2 ST system. The kit comprises a metal enclosure with a power supply, a door expander and a network access controller. MC16-PAC-ST-4-KIT enables the implementation of read-in / read-out access control for four doors using MCT series readers (RS485) In the case of connecting Wiegand or RACS CLK/DTA readers (PRT series readers), the kit enables the operation of four read-in doors or two read-in/read-out doors.