I have just recieved my USB GPIO 64 channels. installed the driver, connected to java by this code: SerialPort port = new SerialPort("COM6"); try { /*Try to open port*/ if(port.openPort() == true){ System.out.println("Port opened successfully..."); } else{ System.exit(0); } this works OK. but now I need to send a digital signal to a specific pin out of 64 pins, like HIGH or LOW , PULLUP or PULLDOWN. How to write that in Java Netbeans ?