Integrating wireless hardware with wired infrastructure is not as difficult as first thought if standards, protocols and interface types are noted and followed. Difficulties arise where proprietary hardware is used and users find that there are compatibility issues. A wireless network can be combined with a wired network by means of a switch, access point router, gateway or bridge. An access point can be used to bridge a Wi-fi network to a wired LAN. For this the network must be set up in infrastructure mode. A gateway can be used to connect a Zigbee network to a wired LAN. When using multiple access points or gateways in a large network they need to be interconnected. This is done using a 10/100 Base T connection and a Ethernet switch. Care must be taken when using different protocols such as Modbus or Profibus. Either the devices support modbus/profibus or a tunnel is used through which the IP data packets travel. Manufacturers will be able to clarify this. When using Zigbee devices proprietary nodes may not communicate with standard Zigbee nodes. Proprietary nodes may have the advantage of transmitting more data or data over a longer distance but there may be compatibility issues with those based on the 802.15.4 standard.
A point to point bridge can be used to connect to LAN’s in different locations. A pair of 2.4 radio modems with Ethernet connectivity can be used for distances of up to 3Km while licensed UHF radios can be used for distances up to 80 Km depending on terrain and regulatory laws in a particular region. These laws include the frequency use, the bandwidth and power output of the radios. Some Ethernet radio modems support only one IP address on each side of the bridge. In this case it may be necessary to use an Ethernet I/O converter or Ethernet serial server to connect to multiple IP addresses.
When integrating wireless with wired infrastructure you should expect your service provider to understand the process and protocols involved in your application. They should also be familiar with the interfacing you are using. It may be possible to simulate your application – you should inquire about this. Finally ensure that you arrange to have the system tested in-situ before agreeing to purchase it. Also ensure there is adequate after sales service as your application may change, the operating environment may alter or wireless regulations may be amended.