WIRELESS ALARM TRANSMISSION
Alarm Industry’s Long & Winding Wireless Pursuit
By Lou Fiore
For several decades, the alarm industry has pursued the use of wireless for alarm transmission. The first attempts date back to the early 1970s, perhaps even before. Early attempts used Citizen Band 27 MHz radio technology as well as low band UHF and UHF radios, in the 150 MHz and 450 MHz bands respectively. Some even ventured into the 900 MHz band.
The main reason for this pursuit was freedom from the need to use a telephone company’s facilities and costs for alarm transmission.
Most of these early attempts used “one-way” technology, meaning that signals were sent from a monitored premises to a central station (perhaps through a repeater mounted on a high spot). The result was that no confirmation or acknowledgement of a received signal went back to the monitored premises or supervision of the transmission path.
Even the digital dialer received a “kiss off” signal at the end of a successful transmission and had the ability (albeit crude) to know there was a powered telephone line available. As a result, no Underwriters Laboratories (UL)-listed systems emerged in those early days. Without that UL “stamp of approval,” many alarm companies would not use these systems in the normal course of business, although they did find use in specialized installations, in overseas usage and as backup to other wired technologies.
It wasn’t until the early 1980s that supervision of a transmission path and acknowledgement of a received signal appeared. The first was a Motorola system based on the use of a Motorola mobile radio that garnered a proprietary UL listing and a Repco two-way system that was listed for burglar alarm and fire alarm use. Both were patterned after wired polling systems and, as a result, were able to be used in line security applications.
‘As wireless continues to evolve — and with the introduction of 6G cellular probably around the year 2030 — we may see revolutionary use of wireless into higher speeds.’
With the introduction of Advanced Mobile Phone System (AMPS) cellular in the mid-1980s, wireless took a different turn. Systems such as Repco’s were relegated to high-end systems that required constant supervision (banks, government installations, etc.) and AMPS systems could be used for residential and other, “less secure” uses. We now recognize the AMPS systems as 1G, or the first generation of cellular.
At first the AMPS cellular systems replicated a wireless version of the digital dialer in that they transmitted the same analog information previously sent over a telephone line, but instead over the cellular network. Later versions used the control channel as a digital transmission path. Versions of that carried forward to the 2G, 3G and 4G versions through modern times.
But the use of UHF radio continued using a more modern, sophisticated and powerful technology — the mesh network. Using mesh technology, transceivers (combination transmitter and receiver units) are arranged in a mesh configuration so that a unit or node can both receive from and transmit to up to a given number of its neighbors. The nodes are interconnected with each other in an interlaced structure. This enables an alarm signal or any required signal to hop from one node to the next until it reaches its destination inbound to the central station or outbound to a unit in the field. The network easily grows as new customers are added either along the way or at the other reaches of the mesh.
The network is also self-healing. Since multiple paths are possible, a path disabled by equipment problems or environmental issues can be overcome by the signal taking a different path and the network issue is reported as a trouble.
This updated version of UHF radio is vastly more reliable than any one-way version at only a small incremental cost. Since all units can theoretically operate at near ground level, no repeater sites are required further lowering overall costs.
One factor that is pervasive with the technologies mentioned above is the fact that they communicate at low data rate speeds. But as wireless continues to evolve — and with the introduction of 6G cellular probably around the year 2030 — we may see revolutionary use of wireless into higher speeds. This will allow video and other technologies requiring higher data rates to easily flourish. VMT
LOU FIORE is principal of LTFiore Inc., a past president of the Central Station Alarm Association (CSAA) and former chair of the Alarm Industry Communications Committee (AICC).
