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Updated June 2, 2008 0600am EST

Why is it called Z-Wave?

The company that created the technology is Zensys Corporation hence Z-Wave. Yes to the next question that is always asked, Z-Wave came before ZigBee.

What is the range for Z-Wave? I have a very large house with only about 10 devices and can’t get them to work. The master remote can see three or four at a time, but not all of them.

The required range for Z-Wave certification is 30 meters in-doors — line of sight. The actual in the field, practical through doors and around corners usually works out to be 15 to 20 meters. The nice thing about a Z-Wave mesh network is the more nodes you have the better it gets. With plug-in nodes running well under $30 it is usually not too much of a hardship to add a few in places where coverage is thin. If you were working with PLC or other proprietary RF technologies you would be looking at $200 plus amplifiers and they wouldn’t serve as automation nodes just “repeaters.” For $30 or less, you can get a Z-Wave repeater that can also turn a light on or off.

We are planning to install approximately 100,000 master-nodes in apartments within three years. An important issue is how to replace the master without re-installing the radio-network. Is it possible to read the EEprom and send the content to the serial port or do we have to use the SPI (serial peripheral interface)?

Yes, there are installer tools that will allow you to press the button on an existing Z-Wave device, read the HomeID that is transmitted as a part of the node information frame (NIF) and then create a new primary controller for that Home ID. After a new primary controller is created, you can us the tool to do a network rediscovery and obtain the network topology that way.

Mark Walters, our resident Z-Wave expert, is vice president of the Z-Wave Alliance.