Potential Dangers When Transitioning From POTS to IP

Alarm professionals provide practices for sidestepping the potential POTS hazards.

Let me begin by getting a little sentimental for a moment. When I started and built RMR (recurring monthly revenue) in my alarm company back in the 1970s, there were two key elements; the newly introduced programmable digital dialers, also known as DACT’s (Digital Alarm Communicator Transmitter) and POTS (Plain Old Telephone Service), also known as PSTN (Public Switched Telephone Network).

Now I am sad, yet in a way excited, to truly say I can see the sunset of this technology. What I’d like to focus on here are some of the technical dangers technicians are presently facing in the industry’s transition from POTS to IP (Internet Protocol).

The chief culprit is a technology called VoIP (Voice over Internet Protocol), which appears to the layman as new version of POTS, but is far from it.

Technicians think they are programming a DACT for a POTS line only to find out the telco provider has switched some of the main trunks to VoIP.

You don’t know when this may happen, and it can cause intermittent failure of your critical, sometimes life-safety, communications. It’s a communications minefield.

Recently I had stopped over at one of my favorite security industry trade talk online hangouts, Ken Kirschenbaum’s Alarm Articles (kirschenbaumesq.com/page/alarm-articles). Many of you also know Kirschenbaum, an industry Hall of Famer, from his monthly Legal Briefing column in SSI magazine.

To give you a sense of what’s going on in the field, this month I’d like to share some of these online conversations techs are having on current issues with the intermittent status of POTS.

Jeff Schneller, Acme Fire Alarm Co.
“The past several months we have been experiencing DACT telephone line communications problems. The DACTs are not communicating with the central station and fail. When they fail the kiss-off light remains on but does not signal the panel there is a problem. Tech support from the manufacturer and the central station all feel it is phone line issues.”

Douglas Emery, Iverify
“To combat this I have been recommending that on all new fire alarm systems my company installs we have a secondary line of a different technology (cellular/network/radio). I agree that it is time to start recommending ‘alternative communication’ especially for new systems.”

Dan Zeloof, Inner Security Systems
“We found out that the provider could program their equipment to route the call to whomever is cheaper. We’ve instructed our provider to use AT&T routing once we found out that there is such a thing as being able to choose. We get a spreadsheet of all our calls and figure out who the carrier was on a misdirected signal.”

Mike Fletcher, Florida Alarm School LLC
“The best fix available today seems to be asking the provider to configure the VoIP or digital line as a fax line. This means the carrier will select a codec [coder/decoder] protocol that does not use any fancy compression or features to conserve bandwidth and is more likely to code and decode the fax and/or dialer data accurately. THIS IS A BAND-AID ONLY!!!”

Ron Wies, Monitoring America Alarm Co-Op
“Alarms communicate just fine on VoIP. However, when a call is routed with no control the alarm communication may transition back and forth between SIP [VoIP] and TDM [POTS]. It’s this transition between the two technologies where the problems occur.”

Packets are dropped and the communication is scrambled. We have contracted with a telephone provider who offers controlled SIP service. Now when one of our alarm monitoring phone numbers are dialed the call is routed SIP from subscriber to our alarm receiver. We get a clean signal and no longer have communication problems regarding VoIP or POTS sunset issues.”

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About the Author


Bob is currently a Security Sales & Integration "Tech Talk" columnist and a contributing technical writer. Bob installed his first DIY home intercom system at the age of 13, and formally started his technology career as a Navy communication electronics technician during the Vietnam War. He then attended the Milwaukee School of Engineering and went on to complete a Security Management program at Milwaukee Area Technical College. Since 1976, Bob has served in a variety of technical, training and project management positions with organizations such ADT, Rollins, National Guardian, Lockheed Martin, American Alarm Supply, Sonitrol and Ingersoll Rand. Early in his career, Bob started and operated his own alarm dealership. He has also served as treasurer of the Wisconsin Burglar and Fire Alarm Association and on Security Industry Association (SIA) standards committees. Bob also provides media and training consulting to the security industry.

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2 Responses to “Potential Dangers When Transitioning From POTS to IP”

  1. Josh M. says:

    I’m amazed, in 2017 at the quotes in this article.

    The best solution is IP/cellular/radio alarm transmission. We haven’t brought on a new account in 4 years and connected it to POTS. We actively discuss upgrading communication and the POTS issues with our existing customer base, and have been very successful migrating them. If you’re not, your asking for a problem, and missing a sales opportunity in equipment and a bump up in RMR.

  2. Gary Himert says:

    If your client is hung up on using VoIP, and won’t fund 2-way radio, cell or other alternative communication method, you can also get the VoIP provider to install an ATA (Analog Terminal Adapter) that is designed for conversion from VoIP to analog. Cisco’s ATA also contains some circuitry to allow for better communication with analog devices such as fax machines, modems and FA/BA systems. The unfortunate part of using an ATA is when the network connection to the ATA is lost, it doesn’t cause a loss of voltage on the analog side (It uses a wall-wort, another issue because people unplug them), and therefore the FACP won’t indicate trouble until the next dialer test, when it fails. It also means that during a power failure, your signals may not be sent unless the ATA is powered via UPS or an emergency circuit. The call manager will know the ATA has fallen off, but that would require either configuration of an SNMP trap to report, or somebody looking for it. Bottom line, you as installer or integrator won’t be notified until FACP shows trouble. And then, likely not via your central station but via sub calling to report a trouble on the FACP, hopefully. We almost always use a secondary means such as dedicated internet device, radio or cell because of the uncertainty of VoIP and the issues with providers and call routing as well. Bottom line is we used to accept an RJ-31X jack as an absolute, but now unless the customer fully divulges what is behind the curtain of the RJ-31X/analog/POTS connection, you should doubt it’s reliability for alarm use. Don’t get me wrong, VoIP is a good thing, but it’s no friend of the alarm industry and devices engineered for analog service.

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