WiFi Here and Now

Access, video and building controls are all going wireless. Here’s what you need to know to wade through the talk and into real applications.

Imagine a world where all the security devices in your building can communicate with the HVAC devices, which in turn communicate with all the lighting controls, and there is not a single piece of wire between them. As you near the entrance, a motion sensor detects your presence, the system recognizes your credential, unlocks the door, and turns on the lights and HVAC.

Imagine a world where you can add security devices, lighting control modules or building automation devices without the inconvenience or cost of running wire. The office can be rearranged quickly and inexpensively. Any wireless device added will automatically become part of a wireless personal area network and can be configured from any PC on the corporate LAN.

These scenarios now exist only in our imaginations, but given the pace at which wireless technology is moving, they may be reality sooner than we think.

In the Rear View
In the mid 1980s, wireless burglar alarm systems became popular, with models like the Ademco 5700 series. They were bulky, had reduced battery life and were purpose-built for security applications, but they were pretty reliable. Door contacts, motion PIR, glass-break detectors, panic push buttons and smoke detectors also joined the wireless ranks during this time.

By the mid 1990s wireless devices had become smaller and had more battery life because of lower power consumption. Their advanced circuitry also allowed for longer transmission ranges. But the existing technology still had limitations.

Burglar alarm systems

    No compatibility between different manufacturers’ products.
  • Frequencies of transmitter and communications protocols were unique to each manufacturer, resulting in no sharing of devices.
  • No compatibility even between various versions of the same product by the same manufacturer. CCTV
  • Point-to-point wireless video transmission only.

Access control

  • Wireless card reader communications back to the field control panel limited by functionality and distance.
  • Little in two-way communications.

What did these systems offer?

  • Purpose-built receivers—Typically a burglar alarm receiver that could communicate directly with the burglar alarm panel. This receiver was powered by the panel and did not depend on self-contained batteries for its operation.
  • Purpose-built transmitters—Door contacts, motion detectors, glass break detectors, panic/hold up buttons and even smoke detectors for residential applications.
  • Built-in batteries offered long life.
  • Remote key fobs allowed for remote arming and disarming of the system.

The principal objective of wireless security was to limit the cost and increase the speed and simplicity of installation. Tom Rosback, vice president of engineering and technology for Honeywell Automation & Control Solutions, says that when Ademco (now a Honeywell subsidiary) produced its wireless burglar alarm system in the early 1990s, it reduced the average installation time from 20 hours to four hours.

You Are Here
In the past five years a plethora of sophisticated wireless solutions has hit the market. Many proprietary systems have started providing monitoring points and control outputs for other systems, making them more flexible. Some manufacturers have taken the readily available PC wireless connectivity standards 802.11.g and 802.11.n as the foundation of a more generic product range. Increasing sophistication allows for increased security of signals, encryption of data and security of devices—linking or pairing Tx with Rx and eliminating errant signals affecting security.

Access control and CCTV wireless implementations have up to now been in large measure point-to-point “wireless elimination” solutions rather than fully wireless solutions. That changed with the advent of wireless LANS, which allow for more complicated connections. New wireless technologies include:

  • Peer-to-peer or point-to-point, with network gateway access
  • Bluetooth
  • Mesh
  • ZigBee
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