In a complex model (see the figure) these devices can all be made to interact, so that computers can be used to monitor the monitors and gather information from throughout a building. The computers can then send messages to humans based on threshholds established for the monitors. In a simpler model, a computer can just wirelessly send a document to a printer for printing. In either case, the advantage of wireless-equipment is flexibility and mobility.

The figure shows a building near a river. Wireless devices are in place to monitor machinery, the environment and for computing purposes. All the information from these devices can be pulled into a central spot, for administrators to track what is going on, and react. If the water sensors need to move, wires are still not needed.

Cost
As with any new technology, the first wireless devices cost more than similar wired devices. Today a wireless Wi-Fi card for a computer costs $69, while a wired Wi-Fi card costs $49. Installing wiring shifts the cost benefit in favor of wireless devices -- especially in a building where the cost of placing anything in an established wall or ceiling is high.

Proprietary Hardware/Software

Depending upon the vendor, similar devices may be proprietary (made by only a single vendor or small group of vendors) or open standard (made by many vendors). For example, the Wi-Fi standard is in use in the vast majority of applications today.

Sometimes a proprietary solution is appropriate, even though it may be more difficult and more costly to add to a proprietary solution -- and it limits the choice of vendors. Similarly, the vendor may go out of business or decide to stop supporting the given item.

Open standard solutions also bring risks since the technology is still relatively new. Sometimes equipment from different vendors does not work together as expected, even if that equipment is supposed to support the same standard.

For example, there was a rush to market by hardware vendors to support the new higher speed 802.11g Wi-Fi standard before that standard was finalized. The devices were close to the standard, but didn't always work together properly -- especially if they came from different vendors.

TIP: Have a building survey conducted before deciding upon a wireless course. This will show how many wireless connection spots (access points) will be required -- and the ranges of the wireless devices given a building's location and construction. The audit typically takes a few hours, using signal strength meters, but it will reduce the number of access points and decrease the time and cost to implement a wireless solution.