Null cable is used to transfer data and basic networking through your digital satellite receiver so it can be used by connecting one end of the null to your pc and the other to your digital satellite receiver which will enable you to transfer your latest software updates to your digital satellite receiver. This null cable is suitable for Technomate, Dreambox, Humax, Manhattan and any other digital satellite receiver with a serial port. It has 9 pin and they call rs232 as well. Most of the receivers use serial cable for their updates so you may need one; But although most of the latest laptops and pc computers doesn't have serial com port so you can always buy a usb to serial converter to convert your usb port in to serial port so you can patch your satellite receiver.