How it works: The CM17A computer interface plugs into a serial port on the back of your computer. Using the downloaded software, you can control X10 automation modules via an onscreen virtual PalmPad on your desktop. You can choose the controller type that appears; PalmPad, Slimfire, or Digipad. The way it works is simple: When you click one of the onscreen PalmPad's buttons, your computer uses the interface to generate the corresponding X10 radio frequency (RF) signal that is radioed to any X10 transceiver module or security system base receiver which then sends those signals out onto your house wiring to control wall switch, lamp, and appliance modules and can even switch X10 cameras. The through-port design of the FireCracker interface allows you to plug another device into the back of it. This way you don't need to lose a serial port to use it. To use another device connected to the serial port, just simply close the FireCracker software. This interface can control all 16 housecodes for a total of 256 different X10 addresses.