Industrial, Construction Equipment, First UD constantly detects the parking bay’s presence status via Ultrasonic wave, if it detect any vehicle parking on the space, the LED Indicator who is coupled to, the UD will automatically change to RED, otherwise the Indicator turn on GREEN, Meanwhile the UD will immediately transmit the status of itself to ZCU, ZCU collect and forward the information to CCU, CCU process those data, then send relevant, Construction Equipment and Machinery ...