Wow, how many house's do you have? Just kidding! Your miss using house code when you should be using unit code since you only have one house. However, you may want to use for example "A" for your camera's and motion sensors and lights, and use "C" for your appliance's and/or security alarms and door/window sensors. By doing so you easily controll 16 combos of lights/cameras/etc on one remote with one letter code on it and not have to use a screwdriver or coin to change the house code every five minutes. Once your thinking "unit" instead of "house" you will make everything easier to use and you'll start to understand how versitile x10 really can be. Your only limit is your own ability to come up with new way's to use it and more money to expand what your doing with it...by buying more modules! Have fun with it! Don't get too serious or frustraited and if needed re-read the papers that come with each unit since it may not have made since the first time you read them, but they will make sense as you become more familiar with how and what each module is capable of doing! I hope this helped...have fun!