How X10 Works

How X10 Works

In the past, if you wanted to be able to control certain lights and appliances from one location, you would have to run hundreds of feet of wire to route the power switches of each device to one location. Using X10 modules you don’t have to do this since the X10 House/Unit codes and commands are transmitted over your existing house wiring.

House Codes and Unit Codes

In order to control specific devices, all modules are assigned an address, which consists of a House code and a Unit code. There are 16 House codes (A through P) and 16 Unit codes (1 through 16). This means there are 256 possible addresses. House/Unit codes are referred to in the following manner: A5, C7, M13, P4, etc.

When you wish to turn on an X10-controlled lamp, you have to tell the lamp module controlling that lamp to turn on. The lamp module is monitoring the power line for a command specifically addressed to it. In other words, any command sent must be preceded by an address (House/Unit code) matching the lamp module’s address. Let’s say the lamp module’s address is set to A5. The lamp module will not respond until it “sees” the A5 “ON” command on the power line.

Note: There are exceptions to this rule. Most modules will respond to special commands that are addressed to a “group” of modules. One example is the “All Lights On” command. Any lamp modules set to the House code for which this command was issued (e.g. House code A) will turn on when this command is transmitted.

Confused? Let’s look at the same thing a different way.

Imagine you have a room that contains 256 people. They are divided into 16 different groups and each group is assigned a letter (A through P). Each member of the groups is assigned a number (1 through 16). So as there is no confusion, each person in the room wears a label that has the letter of their group and their number in the group on it.

You are standing on a stage at the front of the room and everyone is listening to you. You issue a command “A7 take one step forward” and a man wearing the label reading A7 obeys your instruction. This example parallels commanding a specific X10-controlled lamp or appliance to turn on or off.

Your next instruction is slightly different. “Women in J group take one step forward”. Several women step forward, but none of the men in J group respond. This is equivalent to the “All Lights On” command, where lamp modules assigned to a certain House code respond. Appliance modules with the same House code do not respond to an “All Lights On” command.

Establishing Communication

To demonstrate how X10 devices communicate we will look at an example of a simple X10 configuration. We will use three X10 products: a remote control, a transceiver and a lamp module.

HR10 Palm Pad Remote TM13 Transceiver LM12 Lamp Module

Let’s take a moment to go over the basic descriptions and functions of the components we will be using in our example.

The HR10 Palm Pad Remote is a battery-operated, radio frequency (RF) transmitter. It is used for turning devices on and off and it can send dim or brighten commands to lamp modules. The Palm Pad remote can control all House codes and Unit codes (256 possible codes); however its House code dial can only be set to one House code at a time. Although X10 commands can be sent from plug-in transmitters, the system is very much enhanced by using wireless (radio frequency) remote controls that are not restricted to a fixed position.

The TM13 Transceiver (short for transmitter/receiver) is an AC powered device with an antenna on its side. It has three functions:

Receive X10 RF commands

Transmit X10 power line commands

Function as an appliance module

The TM13 Transceiver receives RF command signals sent by the Palm Pad Remote. It decodes the signals and then transmits a power line command signal on the house wiring in the proper format to reach an X10 module, such as a lamp module.

The LM12 Lamp Module is a receiver. It has the ability to control a lamp plugged into the socket on the front in response to commands it received from the power lines. Lamp modules have the ability to dim and brighten lamps as well as switching them on and off, but they only work with incandescent lamps (i.e. they cannot control fluorescent or low voltage lamps, or appliances such as fans).

Setup of our example is quick and easy:

Configuring the Palm Pad Remote

Insert four AA batteries into the Palm Pad’s battery compartment.

Set the House code dial on the Palm Pad to “A”. The dial is located on the bottom left corner of the remote

Set the Unit Selection switch to “1-8”. The switch is located on the bottom right corner of the remote.

Press one of the ON or OFF buttons. You should see the LED at the top of the remote blink. This confirms that the Palm Pad is operating.

Configuring the TM13 Transceiver

Set the House code dial on the face of the unit to “A”.

Temporarily plug an incandescent lamp into the outlet at the bottom of the Transceiver. (Make sure the lamp’s power switch is on if it has one.)

Plug the Transceiver into an AC outlet.

Press the ON/OFF button on the face of the unit. You should hear the relay inside click, and the lamp will turn on. This verifies that the Transceiver is connected to power and is ready to send and receive commands.

Press the ON/OFF button again to turn off the lamp.

Extend the Transceiver’s antenna in an upright position.

Configuring the LM12 Lamp Module

Set the House code dial to “A”.

Set the Unit code dial to “2”.

Plug the Lamp module into an AC outlet.

Plug in the lamp you wish to control. (Make sure the lamp’s power switch is on if it has one.)

Note: the Lamp module should not be used to control touch lamps or lamps that already have a built-in dimmer.

We are now ready to test the system. You will notice that all the equipment has been set to the same House code. If the devices were not set to the same House code this example would fail to work.

We will now confirm that the TM13 Transceiver will respond to commands sent by the Palm Pad Remote and that the Lamp Module can in turn respond to the commands sent by the Transceiver.

Confirming RF Communication

Since the default Unit code for the Transceiver is 1, we will send the ON command for Unit 1. Press the ON button on the top row of the Palm Pad Remote.

You should hear the relay inside the Transceiver click on. The click confirms the Palm Pad Remote is transmitting correctly and that the Transceiver is receiving and responding to commands. (If you do not hear the click, try the OFF button instead in case the Transceiver’s relay was already on.)

Testing the Lamp Module

Press the ON button on the Palm Pad Remote for Unit 2 (second row).

A moment later the light should turn on.

Press the OFF button for Unit 2.

A moment later the light should turn off.

Note: Allow one or two seconds between commands as there is a slight delay while signals are sent.

Congratulations! You have just set up your first X10 system!

What’s Happening Behind the Scenes?

So the example worked, but what does it all mean? How does it all work?

When a button on the Palm Pad is pressed, it transmits a radio frequency (RF) signal. The Transceiver detects the RF signal and extracts the information (the House/Unit code and command). Next, the Transceiver encodes the House/Unit code and command into the proper X10 power line carrier format and transmits it on your house wiring. If the House/Unit code matches the Transceiver's House/Unit code, it will respond to the command (ON/OFF only).

The power line command travels along your house wiring. The Lamp Module is monitoring the power line for X10 commands. When it detects an X10 command, it checks to see if the House/Unit code matches its House/Unit code. If it matches, it follows the command given, provided it is a command that the Lamp Module can accept.

Confused? Let's think of the three devices (Palm Pad, Transceiver, and Lamp Module) as people. The Palm Pad is a person who speaks French. The Lamp Module is person who speaks English. The Transceiver is a person who speaks French and English. The French person wants to tell the English person to turn on the light switch. Since they speak different languages, the English person will not understand any instructions to turn on the light. This is where the French-English speaker comes in to translate. This is the essence of the X10 addressable module system.