The GSM SMS Controller-Alarm S130 is a universal GSM Remote Control switch and GSM Alarm Unit. it provides 2 digital inputs, 2 relay outputs(3A@240VAC, one is link-output relay, special for switch on or off appliance while the system alarm, another is independent output relay, it can be switched on or off by SMS commands.), and USB Serial Port. It allows you to monitor and control an alarm or remote stations or equipments or machines by SMS.