What is X10?

X10 is a powerline carried (PLC) signaling language that enables control signals to be transmitted anywhere in your house over your existing 100V electrical lines. Simply plug in a controller (transmitter) at one electrical outlet and plug in a module (receiver) at any other outlet and you have remote control of that module! This enables you to have remote and automated control of lights and appliances from anywhere on your property.

The convenience and security of controlling all your lights and appliances from anywhere in your house is simple and inexpensive. Turn on all downstairs lights with the touch of one button as you enter the front door, then push another button to turn on all upstairs lights. From another console at your bedside, turn on your electric space heater. When morning comes, a simple, plug-in timer console automatically turns off your heater, turns on some soft music and starts your coffee maker. All easily done through the magic of X10 signals communicating from one device to another through your existing 110V household wiring system!!!

X10 offers the home automation hobbyist and professional numerous and important advantages, including:

Low Cost (both the X10 components themselves, and the fact that they run over existing household wiring, so you don't have to install new wiring).
Flexibility
Ease of Use
Ease of Purchase.

X10's advantages are not to be underestimated. Everyone in the home automation industry owes a debt to X10 (USA), and its parent company, Hong Kong-based X10, Ltd., for releasing an inexpensive and versatile product that has helped popularize the concept of home automation.

There are, however, persistent questions about X10's reliability. X10's detractors, and there are many, call it a "press-and-pray" technology—meaning, you press the button on the controller or input device (typically, a remote control), and pray that the command actually executes. However, X10 proponents—and there are also many—say that X10 is quite reliable if installed properly.

How X10 Works

At its simplest, an X10 system consists of four parts:

"Transceivers" such as tabletop control boxes or wall modules that send a control signal to a lamp or appliance.
Lamp or appliance modules that receive control signals and turn the associated lamp or appliance on or off.
Portable input devices such as remote controls and keychain remote controls that let you communicate with transceivers via radio frequency (RF).
The AC power lines that carry the signal from transceiver to lamp or appliance module.

The difference between lamp and appliance modules is that the appliance modules will not relay signals, such as a dimming signal, that are fine for lights but might burn out a motor.

The modules are chunky rectangular units a couple of inches on a side that you plug into ordinary power outlets. You then plug the power cord of the lamp or appliance you wish to control into the module, and twist a couple of dials on the module to give that lamp an address, such as A-1.

When you want to control the lamp—say, turn it on or off—you use your remote control or tabletop control box to send the appropriate command to "A-1." The command is conveyed via the home's power lines and received by the receiver, which executes it.

Adding Complexity

Hardware Options

X10 installations can get quite complicated. You can, for instance, buy transceivers with built-in timers that you can set so that devices automatically turn on and off at prescribed times.

You can also buy transceivers that detect motion (so for instance, a light can be made to turn on when someone enters a room), or the level of ambient light (so your driveway lights go on at dusk and off at dawn, for instance). Automated features such as these dramatically increase the usefulness of an X10 installation.

You can also use more-sophisticated controllers that can be programmed via macros or a scripting language. Typically, these connect to a PC via a serial link, and are programmed via software that runs on Windows, DOS, Unix (especially Linux), or the Macintosh OS. Once the program is written, it is downloaded to the controller, so that the controller (and the house!) works even when the PC is off.

Software Options

The software varies in ease of use, sophistication of its graphical user interface, and, of course, programming power. Most offer the ability to "chain" commands using Boolean operators (if…then…else…and…or…). They also allow you to schedule commands over weeks or months, and to use external events as a "trigger" for commands. For instance, you could program a system that alerts you, via floodlights and your household alarm system, if there's a broken window or if someone enters the pool area.

These devices also let you control multiple devices at once so that a single press of a button allows you to control lights and appliances throughout the house. You could, for instance, program a "good morning" routine that gets the coffee-maker going, opens the drapes, shuts the outdoor lights, etc.—all with the press of a button. (And if you use a dawn/dusk detector, you don't even have to press!)

X10 Pro, the "professional" arm of X10 (USA), sells a popular controller (model CM11A) which plugs into the serial port of your PC, and can be programmed via the PC. JDS Technologies' Time Commander Plus is another popular controller. Each comes with its own macro/scripting language.

You can also purchase software that works with a variety of controllers, such as Automated Living's HAL 2000 and Savoy Automation's CyberHouse. Those using Macintosh computers should check out Always Thinking Home or Sand Hill Technologies' x-tension.

Another area where you can enhance X10 is on the input. HAL 2000 and other products add voice-control, so you can actually verbally command your house to, say, raise the temperature. Other input devices include infrared-enabled remote-controls (and even smaller keychains) you carry around with you. While you might like a tabletop controller on the kitchen countertop, living room coffee table, or bedroom nightstand, portability is an asset in other situations.

Conclusion

With X10, you can control up to 256 devices per X10 controller. (Their addresses are A-1 through A-16, B-1 through B-16, etc., all the way up to P-16.) If you're truly dedicated, however, you can use multiple controllers and bust through that limit. You can also give several devices the same address (for instance, A-1), so that you can control them all with a single command. That's particularly good for setting up an "emergency" sequence that floods the house with light and sounds all the alarms.

X10 is the inexpensive and fun starting point for anyone who wants to begin experimenting with home automation. You'll find plenty of help both on our site, X10's site, and the comp.home.automation newsgroup.