Z-Wave
From Wikipedia, the free encyclopedia
Z-Wave is the interoperable wireless communication protocol developed by Danish company Zensys and the Z-Wave Alliance. It is designed for low-power and low-bandwidth appliances, such as home automation and sensor networks.
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[edit] Z-Wave Alliance
The Z-Wave Alliance is a consortium of more than one hundred independent manufacturers who have agreed to build wireless home control products based on the Z-Wave standard. Principal members include Danfoss, Intel, Intermatic, Leviton, Monster Cable, Universal Electronics, Wayne-Dalton and Zensys.
[edit] Radio specifications
Bandwidth: 9,600 bit/s or 40 Kbit/s, fully interoperable
Range: Approximately 100 feet (or 30 meters) assuming "open air" conditions, with reduced range indoors depending on building materials, etc.
Frequency band: The Z-Wave Radio uses the 900 MHz ISM band. In the US this is 908.42 MHz and in Europe 868.42 MHz.
[edit] Radio specifics
In Europe, the 868 MHz band has a 1% duty cycle limitation, meaning that a Z-wave unit can only transmit 1% of the time. This limitation is not present in the US 908 MHz band, but US legislation imposes a 1 mW transmission power limit (as opposed to 25 mW in Europe). Z-wave units can be in power-save mode and only be active 0.1% of the time, thus reducing power consumption dramatically.
[edit] Topology and routing
Z-wave uses an intelligent Mesh network topology and has no master node. A message from node A to node C can be successfully delivered even if the two nodes are not within range providing that a third node B can communicate with nodes A and C. If the preferred route is unavailable, the message originator will attempt other routes until a path is found to the "C" node. Therefore a Z-wave network can span much further than the radio range of a single unit. In order for Z-wave units to be able to route unsolicited messages, they cannot be in sleep mode. Therefore, most battery-operated devices will opt not to be repeater units. A Z-wave network can consist of up to 232 units with the option of bridging networks if more units are required.
[edit] Application areas
Z-Wave is today's most widely used RF technology for remote control devices. Z-Wave technology with low power consumption, 2-way RF, mesh networking technology and battery-to-battery support is well suited for sensors and control units.
Z-Wave innovative mesh networking technology routes 2-way command signals from one Z-Wave device to another around obstacles or radio dead spots that might occurr.
Z-wave technology may not be suitable for streaming audio/video applications.
