256 Possible Addresses

Questions

Since there are 256 possible addresses, am I limited to 256 controlled devices?

Answer

While there are only 256 "individual" X10 addresses - sixteen (16) different House Codes "A-P", with each House Code having sixteen (16) different Unit Codes 1-16, in most homes, there are a number of lights that are always turned ON/OFF around the same time of day.

With X10 modules, each light could be assigned their own address (ie A1, A2, A3, A4, A5, etc.), but then turning ON/OFF all of those lights individually would take some time. Instead, these lights could be set to the same address, (ie. A1), requiring only a single command issued to turn ON/OFF the entire group of lights.

Technically, there is no limit to the number of devices you can control IF items are put in groups to perform the same functions simultaneously.