The SX-2000CI is a control input of the matrix system and can be mounted in an EIA equipment rack (1 U size). Multiple units can be decentralized in a whole system. It is equipped with 32 control input channels. Control input line failure can be detected by connecting resistors to its line. The indicators on the front panel monitor the control input line status. The SX-2000CI has a function to supply a stabilized 24 V DC. The SX-2000CI has two power inputs and can support a dual-redundant power supply system. By using a stand-alone mode, system can be configured with only the SX-2000CI, SX-2000CO Control output unit and the power supply unit, permitting the contact data of multiple channels to be transmitted to the remote locations with simple wiring.