User's Manual

2
About Viconics Wireless Mesh Networks
The Viconics Wireless Gateway (VWG) and related wireless thermostat family (VT7xxxXxxxxW) networkable
devices operate using ZigBee/IEEE 802.15.4 physical layer for communication.
General characteristics of the wireless physical communication layer are:
• Uses a wireless physical layer of 2.4GHz with a data rates of 250 kbps
• Yields high throughput and low latency
• Automatic multiple topologies configuration: star, peer-to-peer, mesh
• Fully handshake protocol for transfer reliability
• Range: 30 feet / 10M typical (up to 100 feet / 30 M based on environment)
IEEE 802.15.4 along with ZigBee’s Network and Application Support Layer provide:
• Low cost installation deployment
• Ease of implementation
• Reliable data transfer
• Short range operation
• Very low power consumption
• Appropriate levels of security
The VWG acts as network coordinator device for the IEEE 802.15.4/ZigBee network used with the Viconics
wireless thermostats.
Many network specific features of the IEEE 802.15.4 standard are not covered in detail in this paper.
However, these are necessary for the efficient operation of a ZigBee network. These features of the network
physical layer include receiver energy detection, link quality indication and clear channel assessment. Both
contention-based and contention-free channel access methods are supported with a maximum packet size of
128 bytes, which includes a variable payload up to 104 bytes. Also employed are 64-bit IEEE and 16-bit short
addressing, supporting over 65,000 nodes per network. All those properties of the physical layer are used and
employed by the Viconics mesh network but are hidden to the installed / user for ease of configuration and
commissioning of the network database.
A maximum of 30
networkable thermostats can be supported by a single VWG. Database creation and
configuration is easily made using a Viconics software appliance that communicates with the VWG.