On the Radar
Updated October 1, 2006 13:00 PST
Q&A with Mark Walters
Z-Wave products are hitting the market left and right.
With the growing interest in home control and automation,
wireless technology is gaining substantial ground. We asked
Mark Walters, head of the Z-Wave Alliance - an organization
that is bringing order to the growing cluster of companies
creating products around the technology - to shed light
on this market and where it's going.
ZWaveWorld: What is Z-Wave?
Mark Walters: Z-Wave is a radio frequency technology
that many manufacturers use in their products so that their
products can communicate with each other and form intelligent
networks. These networks provide for applications such as
automated lighting, one button "scene" or "mode"
control of the environment - for instance, in Movie Scene,
press one button on a handheld remote and you turn on all
of the A/V equipment to watch a movie, the curtains close,
lights dim, heat in the room is set up three degrees. Or
Leaving Home Scene, one button and all the lights are turned
off, HVAC is setback to power saving mode, doors and windows
are locked and alarm is armed.
ZWW: Just how big is the Z-Wave world today? How
many companies are making products or are planning to? How
many products are on the market?
MW: Today the Z-Wave world is just getting started,
with many companies planning their product launches for
the fall season of 2006. There are over 100 different companies
with product development underway and over 60 fully interoperable
products on the shelves in the United States. These numbers
will more than double in the next year.
ZWW: How does Z-Wave differ from other approaches,
and can you give us a little background, some historical
context? .
MW: Z-Wave uses a new technology called mesh networking.
In a mesh-network any product can act as a relay device
between two other products that are communicating with each
other. Think of a spider web, where there are many different
threads you can traverse to get to the center from the edge.
This ability to choose from many different paths for communication
between two devices provides for extremely robust performance
even in harsh application environments. In older power-line
technologies, if there is interference on the power line
caused by, say, a hair dryer or cell phone charger, between
two devices that need to communicate, they have no ability
to route their communication around that interference.
Z-Wave mesh technology is completely "two-way,"
in that every message sent is confirmed by its receiver
forming closed-loop or reliable communications. This is
not true of many of the older home control technologies.
With Z-Wave technology the more devices you have in your
network the stronger it is as it increases the number of
communication routes. With power line technologies - like
X10 and Insteon - the opposite is true, in that more devices
do not increase the number of routes. In addition, even
though some of the newer power line devices claim to relay
for each other, the hidden secret is each time you add a
power line relay device to the power line it acts as a partial
short circuit and pretty soon - with around 20 devices in
a typical home - it gets very hard to get any communications
down the power line. As a result, most power line devices
are receivers only and cannot act as relay devices or provide
two-way closed-loop acknowledgment of received messages.
Z-Wave communicates at data rates of up to 40,000 bits
per second, whereas X10 communicates at 120 bits per second.
Z-Wave can accomplish in a few milliseconds what it would
take X10 several seconds to accomplish.
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