A Quantum Leap

Following telecommunications’ lead, fire industry also could seek benefit from the Web

• By Nick Martello
• May 26, 2009

The monitoring of fire alarm communications via phone lines, one primary line and one secondary line for backup, has been the industry standard since the mid-1980s. Although telecommunications technologies have improved significantly with the evolution of the Internet, the quality of fire alarm communications has steadily declined in recent years.

The public-switched telephone network was originally a network of fixed-line analog telephone systems. The pair of copper wires that ran from a central switch office to a subscriber’s residence or business was referred to as a subscriber loop. Each central office housed an enormous bank of lead acid batteries used for back-up power in the event of an outage.

Today, only the older parts of the PSTN use analog technology, and many new telecommunications provider installations use digital systems. Advances in digital communications and increased use of fiber-optic cable in place of copper wire have greatly benefited the likes of AT&T, Sprint and Verizon. It is less costly for telecommunications providers to use multiplexed systems that remove the need for thousands of separate copper pairs to each subscriber. Experts say fierce competition among service providers to offer a wider range of television, voice and Internet services is the impetus for the rapid reduction in analog technology.

Many devices, including fire alarm control panels, primarily operate via analog signals. The original 48 DC voltage supplied by subscriber analog circuits -- known in the industry as plain old telephone systems -- also has declined to as little as 6 volts of off-hook voltage. As a result, communications between new and existing installations of both fire and security alarm panels have become particularly dicey.

Boxes supplied by service providers to convert signals from digital to analog are a common patch that’s garnered mixed results. Unfortunately, increased incidents of trouble alarms have come about from this patch’s analog-to-digital conversion at the subscriber end or the central office, followed by the digital-to-analog reconversion at the central station.

Code Considerations
Two hard copper phone lines have traditionally provided the means for fire alarm communications per NFPA 72 8.6.3.2.1.5(3): “The primary means of transmission shall be a telephone line connected to the public switched network.”

The same section of code advocates another phone line be used as backup to “call a second digital alarm communicator receiver line when the signal transmission sequence to the first called line is unsuccessful.”

For the past 25 to 30 years, the public switched telephone network has provided the best technology for fire alarm communications. But what happens when those two lines contained within the same cable, coming off the same pole into your property, go down? In addition, those central office storehouses of batteries used for back-up power went away with the 1982 divestiture of AT&T.

Today, with the universal presence of the Internet, it appears that an easier, more reliable means for alarm transmissions has evolved. Around the turn of the century, NFPA technical committees were savvy enough to see IP-type digital alarm communications transmitters were to become a real and viable technology. With that, the 2002 National Fire

Alarm Code Handbook was updated to include requirements for IP communications technology. Listed in the current 2007 edition under “Other Transmission Technologies,” section 8.6.4, NFPA 72 stipulates the requirements for using a packet switched data network for alarm communications, and the aforementioned PSTN refers to public circuit-switched telephone network.

IP Rewards
You may have noticed that in diagrams, the Internet is usually depicted as a fluffy cloud. This cloud represents an incomprehensible number of connections throughout a vast number of services. This multipath feature is one of the benefits of using an IP network. Its alternate connections are redundant to an almost infinite degree, which provides an unsurpassed level of integrity. Consequently, per NFPA 72, a backup method such as a secondary phone line is not required when monitoring via IP. Optional backup reporting can be provided by way of another IP address or some other technology such as cellular, radio or telephone communication.

One of IP’s most notable features is its constant supervision. Whether monitoring by phone or IP network, NFPA 72 stipulates the transmission channel should be tested at least once every 24 hours. All of the IP communicators on the market send supervisory test signals much more frequently -- some as often as every 30 seconds. With IP, central stations know there’s a problem with the fire alarm long before the phone line’s 24-hour test and can inform the responsible installing dealer for the account.

Several connections are available for Internet access, such as a satellite dish or a T-1, cable or DSL line to name just a few. In the United States, costs of $60 to $100 per phone line can be avoided when an IP network is already present. As is the case with most commercial properties, one IP line can service numerous personal computers, credit card machines, televisions, data storage servers, intrusion systems and, now, the fire alarm system.

Faster reporting speed is another reward of IP. Current-day DACTs typically tie up a receiver’s phone line for 25 to 35 seconds. During higher traffic or at peak times, a DACT may receive a busy signal from the remote station receiver, resulting in a call-back and additional delay in reporting an alarm. The typical alarm response time needed for an IP transmission is approximately 50 to 70 milliseconds. This quantum leap in speed of fire alarm systems reporting allows for more accounts to report with little or no chance of conflicting traffic at peak times.

The question of security always arises when anything related to the Internet is discussed. When purchasing an IP communicators device, be sure it provides the minimum government standard of 256-bit advanced standard encryption. Models providing 512-bit AES are preferred as that is the highest level of encryption available.

Even if you’re not an IP guru, many models of IP communicators are reportedly simple to install and are backward compatible. With the price of gasoline and labor on the rise, the ability to program a panel, upload historical information and sensitivity settings, and conduct regular system tests from a remote location has become attractive to installers.

Technical Clarifications
As with any new technology, there’s always trepidation about being the first to implement it. For installers, there’s fear of a big learning curve associated with anything related to the Internet. The same goes for AHJs.

Considering this new alarm communications method relies on the integrity of a facility’s Internet or intranet network, an IT department or IP provider should be involved. It’s good to know how this IP alarm monitoring operates. However, given this technology’s ease of installation and high level of reliability, it’s not necessary to go back to school for a degree in computer programming.

A fire alarm’s IP communications equipment could meet the requirements set by NFPA 72 section 8.6.4 “Other Transmission Technologies,” but not be listed to Underwriters Laboratories 864 standards (the latest UL 864 Ninth Edition standards went into effect after January 1, 2009). However, most U.S. local and national codes require the entire fire alarm system still be UL approved.

Remember, to be listed as fully compliant, UL must test the specific IP equipment together with each model of fire alarm system. Aside from a UL listing label affixed to fire alarm equipment or UL listings noted within manufacturers’ data sheets and manuals, this appears to be the only method for obtaining irrefutable evidence of a genuine UL listing.

Confusion between IP and VoIP also needs clarification. It’s becoming more common for the terms to be used interchangeably.

In layman’s terms, VoIP is a combination of hardware and software that enables people to use the Internet as the transmission medium for voice telephone calls or, in this case, fire alarm signals. When VoIP transmits a phone conversation or alarm signal, these analog tones are diced up into numerous digital samples of data and sent via the Internet. It’s not uncommon for a couple of these digital samples to be dropped during the transmission. This is called analog-to-digital sampling. It accounts for those instances when a syllable or two are dropped within a conversation using two, landline phones. This same scenario can happen to VoIP fire alarm panel communications when a sampling of alarm tone or dual tone multi-frequency information is lost in transmission.

On the other hand, an IP network simply packs up all the analog information at the panel into a digital packet and sends it over the Internet or intranet. Upon reaching its destination, the IP receiver unpacks the file, acquiring all pertinent alarm information. The difference being a complete digital representation of the alarm tone information is correctly received at the central station digital receiver.

Lastly, the reliability of the Internet is often called into question because of users’ perceptions of server-based products such as e-mail or Web browsers. Slow-loading Web pages and e-mail server problems give the appearance of a lagging network communications path. In actuality, the network (Intranet or internet) and corresponding switches are as fast as ever. It is the servers supplying the users’ requests that create the perception that the network is slow. Ultimately, these servers play no part in IP communications between fire panels and central stations.

Central Station Considerations
Just as Dunkin Donuts and Starbucks capitalized on America’s newfound love for all things coffee, many central stations are quickly jumping on the IP bandwagon. This is not a bad thing. Quite the contrary. Growing numbers of central stations are equipping themselves with the latest IP receiver technology to grasp its benefits of faster reporting and constant supervision -- features that make for improved customer service.

Many central stations have automation software that can transmit alarm messages to cell phones or other handheld, text-enabled devices. This technology has been in existence for a few years, but many end users are unaware of it.

If a catastrophic episode such as a major weather event destroys incoming phonelines, taking a central station offline, the communications protocol of IP receivers allows for the duplication of receivers in any remote location. Just one central station receiver IP address can service thousands of accounts at a different location instantly. In most cases, if the primary IP receiver fails, the spare or backup receiver automatically registers all subscriber units with no human intervention required. Most central stations utilizing telecommunications monitoring could not afford the cost involved with switching hundreds of incoming phone numbers over to a backup receiver in a different geographic location.

Some IP receivers also enable duplicate monitoring of alarms or trouble conditions by an end user or alarm dealer -- another new subscriber benefit. The remote subscriber cards must support a minimum of two IP addresses for the corresponding primary and backup IP central station receivers. If a third IP address is supported, dealers can set up their own maintenance receiver to be advised of any trouble conditions.

Continuing Advances
With IP, so much is possible. With wireless, anything is possible. Many manufacturers of IP communications equipment have already released or admitted to working on new products that harness global system for mobile communications wireless radio. A cellular radio modem connected to the fire panel could shoot out digital alarm transmissions over a common cellular provider’s towers to a central station via IP, not analog signals. While the primary communications path is a wired/shared IP connection, the cellular data connection can serve as an easily-accessible backup.

Looking past wireless possibilities, the next generations of alarm transmission technologies for fire and security systems could come from any direction. What breakthrough technologies lie past the ever-expanding Internet, land-based cellular towers or satellites floating in space are anybody’s guess.