Alarm dialers are now integrated into most alarm control products. The conventional dialer today is commonly referred to as a “digital dialer.” While it is true that alarm dialers typically communicate digit information to the monitoring station, the reality is that most of the millions of alarm dialers installed today are analog communicators that communicate simple number and/or alphabetical messages to the monitoring station using protocols that are unique to the alarm industry or to a particular alarm manufacturer. (There are some notable exceptions.) As alarm systems have traditionally been specialty applications and not data-communications intensive, this has not been a huge disadvantage so far.

Digital communication as it applies to the rest of the communications world assumes the binary (ones and zeros) coding of information in packets according to accepted communications industry standards.

The nature of monitoring is changing. In the past, customers have only required simple point-of-origin alarm messages, system integrity/status supervision and at times, user open/close information. One of the reasons for this is that the communications infrastructure and customer familiarity with it were minimal and communications costs were relatively high.

Until 1990, the Internet was a network reserved to the U.S. government and educational institutions. The government then allowed commercialization of the Internet and Transmission Control Protocol/ Internet Protocol (TCP/IP) became the standard for digital communication. Since then, the introduction of the hypertext and graphical-oriented World Wide Web, the growth of economical broadband digital communication, the move towards systems integration and the continual emergence of younger, more communication-savvy customers has increased expectations for all types of communication services. Fortunately, hardware manufacturers, software suppliers and monitoring companies in the security business are rising to the challenge.

Monitoring Tomorrow – Life in the Cloud

Leased copper lines are dedicated circuits that are supervised and connected all of the time. Alarm dialer connections via the PSTN are “switched” circuits and create dedicated connections some of the time and then disconnect. Network-based Internet Protocol (IP) communications are “connectionless” but always on. The network is available all of the time and messages are packets that contain address and control data that allow the path between connections to be managed by the network and are delivered nearly instantaneously. Alarm or access control system messages often can be contained in just a single packet. Remote programming, video and other information-intensive communications are broken into a series of packets, routed by the network and re-assembled at the destination.

This “packet-switched” architecture is the basis for all modern communications and IP is the standard protocol.

The cloud that is often illustrated in system diagrams represents the network (both wired and wireless), which routes addressed packets from their origination points to their destination.

Alarm dialers and proprietary protocols will not be going away anytime soon, but they will eventually go away. Even now, manufacturers are considering making dialers optional modules on future alarm controls. The move to IP-based network communications is inevitable. One of the greatest challenges that alarm equipment manufacturers have now is how to make their new products and retrofit network adapters easily installable into the standardized networks that all other communication devices are operating on.

Envelopes, Protocols & Sessions

Data packets on IP networks feature data at the beginning and end of the packets that constitute a digital envelope. The envelope contains address and instruction bits as to how to handle the message data in the middle.

The two notable transport layer protocols used directly for alarm purposes in networks are User Datagram Protocol (UDP) and Transmission Control Protocol (TCP). Formally, these protocols are referred to as UDP/IP and TCP/IP and they are both commonly used communications schemes.

UDP is a non-guaranteed delivery protocol in which the network just passes the packet along to the destination address. It is up to the hardware at each end of the communication path to assure proper delivery of the packet. Typically an alarm system/network module sending a UDP alarm message expects to see a return acknowledgement message by the receiver. If it does not, it reverts to an alternate communication path and/or sounds a local alert. UDP is ideally suited to alarm and access control messaging because the data is small, easy to hand off and does not warrant establishing a durable connection.

TCP is a guaranteed delivery protocol in which the delivery of messages are supervised and assured by the network. The envelope contains information that instructs the network to make sure the packet gets to its addressed location.

Most alarm and access control messages are short enough to not require a UDP or TCP session to be established between end points. Remote programming, video surveillance and video clips often require that the end point hardware or systems know that a more long-lived task is in process and the system and data transmission scheme is designed to keep watching for more information until the operation is complete.

Communication Mediums & Methods

There are only two ways to communicate electronically – with wires or without wires.

By far, the majority of installed monitored alarm systems today are traditional automatic dialers. Monitored commercial fire alarms typically feature dialers with two telephone line connections and are mostly installed and operate in accordance with the UL 864 standard.

Intrusion alarm systems that require higher security are installed with secondary radio transmitters or transceivers, IP network adapters, or a combination of both. In some cases, the radio or the IP network is the primary path and the PSTN dialer is the secondary. Whether an intrusion alarm system is installed with secondary reporting or not is usually determined by insurance requirements, UL certification requirements, customer concern for security or alarm company recommendations. There are very few leased copper electrical or multiplexed alarm connections in service today.

AMPS & Long-Range Radios

The Advanced Mobile Phone System (AMPS) was introduced in the early 1980s and facilitated the formation of the cellular telephone industry in the United States. AMPS is an analog system that operates in the 800 Megahertz (MHz) radio frequency (RF) band and features 832 channels, half of which are designated forward channels and the other half reverse channels. Channel assignment, tower hand-off and mobile handset power settings are managed by a number of channels reserved for control information.

Several alarm industry vendors saw an opportunity to use the cellular system for primary or backup alarm reporting. One approach was to make an adapter that was connected between a cellular transceiver and an alarm dialer and produced a fake dial tone when the dialer went off–hook to report an alarm or supervisory message. This approach uses ordinary AMPS voice channels and communicates directly to a central station receiver.

Another approach was to use spare capacity in the AMPS control channels to transmit alarm event information through a special network and relay the messages to the central station receiver. This method allowed for a very economical means to add security to alarm systems as the control channel radios were not very expensive and the service charges were reasonable.

The majority of the cell phone industry has long since progressed to digital service on higher radio frequencies with wider bandwidth. This allows for enhanced service such as e-mail, Web browsing and even video on the mobile handset.

But just as limited utility copper alarm circuits became more valuable as multiplexed data circuits, the limited utility AMPS service frequencies can be put to better use and are being phased out (AMPS Sunset) by the Federal Communications Commission. Over a million AMPS alarm radio systems are affected and the scheduled “sunset” is February 2008. Several concerns in the alarm industry are petitioning for an extension of this date. The sunset gives carriers the right to terminate AMPS service, but does not mandate it. Some carriers may elect to continue service in certain areas beyond that date.

There are several replacement options for AMPS radios. Replacement radios operate on networks and frequencies owned either by the central station alarm company or a telephone carrier. Radios that operate on the new higher telephone cellular frequencies are now being produced. These radios typically are GSM (Global System for Mobile Communications) radios and use the Short Message Service (SMS) feature of the digital cellular network for alarm messages. Some attractive replacement programs are being offered by suppliers to replace AMPS with GSM radios.

Some central stations own their own radio networks. Typically they operate on UHF radio bands reserved for the security industry. The traditional approach has been to operate on a simple transmitter to tower/repeater to central station basis.

Many legacy systems operate this way. One manufacturer features products that allow the creation of a UHF mesh of radios that all hear each of the other radios within range and will forward outlying radio messages to radios closer-in until the message reaches the central station. This allows the central station to progressively build an increasingly large radio coverage area as more radios are installed at the fringe.


Increasing use of Voice over Internet Protocol (VoIP) presents some challenges for alarm companies. VoIP is an IP network service that replaces all or part of PSTN connections and allows telephone calls over the Internet. A VoIP adapter is connected between a telephone and an Internet router or gateway. It works like a regular phone for the user but it takes analog voice, converts it into data packets and reassembles it at the end gateway, which is connected to a telephone or the PSTN. It works great for voice because the human ear cannot discern small variations in how the analog signal is reconstituted. It can be a problem for some traditional alarm dialers. If an alarm dialer is plugged into a VoIP gateway, the tones may not be recreated at the central station end precisely the way the receiver is designed to accept them. This does not affect all dialers but customers should be cautioned that if they switch their phone service exclusively to VoIP they should test their alarm right away. Workarounds might include adding an IP network adapter to the system, upgrading or even replacing the alarm control. The Central Station Alarm Association (CSAA) and the Alarm Industry Communications Committee (AICC) are addressing this problem. For more information visit their Web site at:

Alarm Processing & Enhanced Services

Twenty or so years ago alarm monitoring was a fairly simple business. The vast majority of alarm systems installed were quiet most of the time and needed little attention. The exceptions were false-alarm problematic customers or installations and business customers that contracted for opening and closing supervision services.

The new communication environment and increasingly sophisticated customer base are continually raising the bar for central station services.

The current generation of alarm control/communicators, receivers, gateways and central station automation systems provide a variety of services that were simply not possible in the past. Alarm dealers that work with wholesale monitoring companies have unprecedented access to their account and customer account data. Alarm end-user customers now can also have access to their specific account information and activity. In some cases the remote access to data is through a PSTN dial-up connection, but much of this is now made possible by the Internet and Web servers operated by monitoring companies Although central station automation software suppliers and hardware manufacturers are providing comprehensive access to account information and history to customers, this industry is still in the beginning stages of open access and advanced premises system services.

Remote Video

Remote video in the central station is still relatively rare, but new technology developments, the growing use of networks and use of the Internet for security are changing this.

The two primary uses for video in the central station are:
  • surveillance and deterrence, and
  • verification of alarms.
There are no standards for video surveillance systems, but a video verification standard is being developed by the CSAA.

A problem with video in the central station is that there are too many cameras to be watched and not enough operators in the central station to watch them. This is actually the same problem that large proprietary facilities and enterprises have. Most of the video that cameras capture and devices record is not important for security purposes. Central station operators and proprietary facility security personnel need help determining the video scenes or clips that are important.

One solution is to incorporate video analytics into the remote system. Video analytics (sometimes referred to as video content analysis (VCA) or intelligent video) has made significant progress in functionality, reliability and economy over the past few years. Video analytics look at things that move within a field-of-view and quantify them as discrete objects. The objects then can be assessed according to a set of rules that determine whether an alert or alarm should be initiated.

Video analytics provide some great advantages for a variety of applications, but because the cost is still relatively high, it is most appropriate for higher end applications. For more economical applications, there are products available that connect conventional analog cameras to IP routers or dialers and will send video clips to the central station and/or to the customer if an intrusion alarm is initiated. Some of these products allow the customer or central station look-in to the premises. Privacy might be a concern with systems that feature look-in capability. One new system is available that features wireless cameras that are normally off and will only transmit a video clip if an alarm is initiated from a built-in PIR.

Verification is an important monitoring issue. Some municipalities are enacting optional police response or no-response policies for alarms that are not verified. Standards exist that allow audio or a return call to an authorized person at the customer’s premises to be sufficient for verifying an alarm, but as the old saying goes: “A picture is worth a thousand words.” Accordingly, five frames of video must be worth five thousand words. Advances in technology will make remote video commonplace in the central station. It is not a matter of if, but of when.

A walk through any local security products distributor showroom will provide a glimpse of the future. One would see structured wiring enclosures including rack-mounted network routers and hubs, CCTV and MATV products and distribution components, audio, home/building automation components and security and fire alarm controllers and accessories.

Convergence is a term that is used in every information-oriented industry almost to the point of annoyance, but it is a reality. Ultimately the monitoring industry will support a blending of services that include alarm supervision, access control administration, video supervision and verification, as well as building/residence automation administration.