How Your Alarm Panel Communicates With Police
Phones, Cellular, Radio or Internet?
How your alarm panel communicates with police is critical. That communication happens between the alarm panel and your central station when there’s an event that requires immediate action such as a break-in or fire. Making sure the communication path between the panel and your central station works reliably and consistently is critical.
People often ask me what the best methods are for communicating with the central station. In this post I list the advantages and disadvantages of the four primary communication methods.
How your alarm panel communicates with the police:
The phone line is the traditional method for transmitting alarms. They’ve been used for many years, but their popularity is beginning to wane. Phone lines have several major drawbacks:
Cost – Many homeowners no longer subscribe to home phone service, or use inexpensive VoIP (Voice over Internet Protocol) services, which are not compatible with traditional alarm systems. Business lines can be expensive to dedicate to an alarm system.
Reliability – Phones are susceptible to reliability issues if the lines are damaged or the telephone provider is doing maintenance.
Speed of Transmission – Phones are also the slowest to transmit messages because they must first dial a phone number, wait for the receiver to acknowledge the call, then transmit the message, sometimes as slowly as 300 baud. At this speed it would take you about 23 hours to download a single song from the Internet! A phone transmission of a fire alarm can take up to two minutes from the time the panel went into alarm—that can mean a world of difference in response.
Easily Bypassed – Phone lines can be tampered with where they enter the building allowing a criminal to effectively disable an alarm system before he even enters the building.
Cellular modems are becoming much more popular in alarm system installations because they have several distinct advantages over other methods:
Cost – While there is a cost for cellular service, this is typically much lower than paying for a phone line.
Reliability – Cellular modems can usually talk to at least two cell towers, so even if one tower goes down, the alarm call can still get through.
Speed of Transmission – Cellular transmissions are typically transmitted in under 30 seconds—a vast improvement over a traditional phone line.
Not Susceptible to Tampering – Unlike phone lines, which run on a copper wire that comes into your building, there’s nothing to cut to disable the system.
Allows Mobile App Integration – While not a necessary component of the alarm system, having a cellular modem makes adding cell phone and tablet apps much easier.
Radio transmitters use a proprietary network to transmit to central stations and have several advantages and disadvantages:
Reliability – Radios can be quite reliable, but because it’s a proprietary network the dealer must build the network on their own. If there are not a lot of radios in the area, you may lose some redundancy.
Speed of Transmission – This can vary depending on whether the alarm panel can integrate directly with the radio, or if the radio uses a form of dialer capture technology, essentially simulating a phone line to the alarm panel and converting that information to a radio signal.
Susceptibility to Tampering – While there’s no phone line to cut, often radio installations will require an antenna to be mounted outside of the building to achieve a good signal on the network. An informed criminal may recognize these antennas and attempt to tamper with them. The signals are monitored for loss, but a loss of signal may not be handled the same as an alarm.
Remote Programming Support Diminished – With most radio installations, the ability of the alarm service company to connect to the alarm panel to make changes is lost. This can lead to more expensive service as technicians will have to go on-site to your location to make any programming changes.
Internet communicators have been available for a while and this list would not be complete without mentioning them. While there are impressive advantages to using these devices, there are also some serious disadvantages you should consider. While some of these cons may seem like unlikely possibilities, it’s important to know what you’re getting into.
Cost – Internet dialers can be extremely cost effective because there is no other additional service fee (assuming you already have high-speed internet.)
Reliability – While the devices themselves are reliable, there are more points of failure when using an internet dialer.
- The Internet Service Provider (ISP) may drop connection.
- The network modem, router and switches may go down, and will probably require some sort of battery backup.
- Network firewalls may interfere with alarm transmission and can be difficult to troubleshoot.
Issues with Domain Name System servers (DNS) or other internet protocols can affect the ability of the communicator reaching the central station.
Speed of Transmission – Internet dialers are very fast and can send alarm events in seconds.
Susceptibility to Tampering – The internet communicator can be tampered with in many ways, from unplugging the network cable from the switch, to cutting power to the building (if the internet modem is not on a battery backup.) Even a malicious computer user “hacking” your network to interfere with the dialer.
Allows Mobile App Integration – Some, but not all, mobile apps will work with internet dialers. Configuration of the router to allow certain ports will usually be required.
While there’s no way to say that any one of these communication methods is going to be ideal in any specific application, you should have a good idea of which method will be the best fit for your installation. Talk to your installer about what methods are available, and what will make the most sense for your alarm needs.
Questions? Shoot me an email.
Seth Stiebinger has more than 10 years experience in the design and integration of systems including fire alarms, access control, video surveillance and sound. He’s been a project manager on numerous large-scale security and fire installations including, Target, Wal-Mart and others. Seth’s an expert at working with equipment from Bosch, DMP, Honeywell and more.