The protocol supports encryption.
Going Wireless
153
The physical network is based on the IEEE 802.15.4 standard for wireless personal
area networks. The transmitters use spread-spectrum technology. In the
U.S., Zigbee systems transmit in the 2.4 GHz or 915 MHz bands. A transmission
can travel up to 50 meters, and routers can extend the distance.
Zigbee supports multiple network topologies, including a mesh topology where
each node can communicate with any other node within range. In a Zigbee network,
one device is the Coordinator, which manages the network. The other
devices are either End Devices, which perform monitoring or control functions,
or Routers, which extend the range of the network and can perform monitoring
or control functions as well.
MaxStream??™s XBee-PRO modem has an asynchronous serial interface and a
ZigBee interface. Data received on the asynchronous serial port transmits on
the ZigBee interface, and data received on the ZigBee interface is written to the
asynchronous serial port. A vendor-specific command mode and API enable
configuring the modem over the asynchronous interface.
For more about Zigbee programming, I recommend the book Hands-On Zig-
Bee by Fred Eady.
&
$
Bluetooth (bluetooth.org) is a hardware and software standard suitable for a
variety of wireless applications. The interface supports secure transmissions at
low power and low cost.
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