VOIP to Replace Security System Hardlines

January 19, 2011 10:34 AM

My alarm system uses one main phone line and one backup phone line to check in with the security service company by, apparently, dialing and transmitting tones to a 1-800 number. Paying $40 each month, even for two measured lines, seems quite unnecessary, if a cheaper "VOIP" replacement could help instead.

Even though there's not a what anyone would consider a telephone in this system, in theory, could some VOIP hardware (e.g.) make the calls over ethernet through my internet connection? Is there an inexpensive provider to just make these 1800 "calls"?

I'd settle for replacing one telephone line if I could. For what it's worth: these sorts of questions seem to confuse the all-too-eager-to-upsell security company -- so at this point I'd rather try something and ask for forgiveness than for permission.

posted by glibhamdreck to computers & internet (9 answers total)

A family friend recently attempted to replace their security system phone line with VOIP (Comcast Digital Voice, I think). It has so far not gone well.

I'm not sure if the problem is just availability of the service, or if it's call quality, but they've had the alarm go off in the middle of the night (because it thought someone had cut the wires, apparently) and scare the bejeezus out of everyone at least once.

The security company was not pleased to learn that their alarm connection was now VOIP instead of copper; basically they said they wouldn't support it. Comcast apparently says that they don't support alarm circuits (and, I assume, any other life-safety applications, like fire alarms or medic-alert systems) over VOIP.

So it's a bit of a mess. But they only have one line connected to the alarm system, so maybe you could get away with taking one of the two lines you have and moving it to VOIP, so that if something went wrong it would still be able to call out on the real copper POTS one. But I wouldn't, based on my friend's experience, try to get rid of the real phone service if you want to keep the alarm system. They just aren't designed to work that way.

If you live in an urban area it might be worth seeing whether your alarm company has systems they can install that don't require a phone line ... that shouldn't confuse them as such systems have existed for years. They use either traditional radio transmitters or, more recently, cell backhaul for the alarm connection. (They may be more common for commercial alarms than residential ones; I have seen them for fire alarm systems in industrial facilities.) But perhaps with a bit of an initial investment you could get something that would be cheaper on an ongoing basis than the two phone lines, if you're not otherwise using them.
posted by Kadin2048 at 10:51 AM on January 19, 2011

A friend of mine put a Asterisk server in his house and is running a security system off it. It texts him if any of the window contacts, etc are triggered. It averted a robbery attempt just last month, while he was out of town for Christmas. Might be worth looking into. Saving $80 a month would probably easily pay for the hardware for the server and the alarm components.
posted by COD at 10:58 AM on January 19, 2011

If this will work you will need an Analog Telephone Adapter (ATA) like the SPA2102 you linked and service from a VoIP provider company such as Vitelity (no monthly fee, $0.0144 per minute outgoing).

The problem is that VoIP uses more aggressive compression codecs that are optimized for human speech. Your security system probably uses a modem that makes noises not typically used by humans and hence they end up mangled, sort of like what happens to music on hold. You will need to set your ATA to use a non-compressing codec such as G.711, which will use a lot more bandwidth and make the whole thing more susceptible to problems if you try to watch youtube while the alarm system is calling home. You could set up a Quality of Service (QoS) system on your home router so VoIP traffic gets the highest priority (some routers support this out of the box, otherwise you will need to install an aftermarket open source firmware such as DD-WRT). Or you could just give it a shot and see what happens.

What happens if your alarm system can't get through to the security company? If there could be lives at stake you probably don't want to mess with it. From reading the manual to your alarm system it looks like it really expects two real phone lines and doesn't appreciate failure. Might be best to either it leave it as is or look for a different alarm system with lower monthly expenses.
posted by ChrisHartley at 10:58 AM on January 19, 2011 [1 favorite]

Professional opinion*: It might work.

The issue you are going to have is that you alarm system is running some type of modem to the 1-800 number. Modems were designed specifically to run over analog phone lines by sending information via tones through the phone line, etc. When you drop a modem onto a VoIP line, such as a fax or credit card machine, you run in to one big problem. VoIP often uses lossy compression. If you try to run a fax that is not meant to run over VoIP on VoIP, the faxes will fail 95%+ of the time. Same goes for credit card machines.

So you need a workaround. In faxes, the work around is T.38 encoding. This is an encoding that sends different tones that will work over most VoIP systems, i.e. works through the lossy compression. Another work around is having VoIP that uses G.711 encoding, which is a higher bandwidth less-lossy compression scheme that handles modems better than other VoIP encoding (such as H.323 compression). Even with the workarounds, failures still occur.

If you talk to the right person at the VoIP provider and explain what it is you are really trying to do, they might be able to help you. The front-line agent at [insert VoIP provider/cable company here] will be clueless. Request a level 2 tech or a manager.

So, it might work. It might not. Most of the telecom guys I deal with prefer to run faxes, credit card machines and the like on regular phone lines to eliminate the VoIP problems entirely. Some people who run the modems over VoIP have no problem.


* - I spend 40 hrs/week working on VoIP telephones, VoIP hybrid systems and analog/digital telephony. I personally would keep the $40/month service.
posted by Mister Fabulous at 11:00 AM on January 19, 2011 [1 favorite]

We have phone service through our cable internet that works perfect with our alarm provider. It's a smaller local provider, and although I don't know the specifics, I do know that they had to be aware of it being a phone through cable, and that they changed something because of that. I know it works because I accidentally set the alarm off once and got the phone call for the security password very soon after. I understand that it's probably not as reliable if there's power outages, but I'm also okay with that, given the cost difference and the expected use of the product (our concerns are more property-related, and we don't have much property!). So, if you're really interested, smaller providers might be more likely to use it, it can work through that system, but it's likely less reliable in some predictable ways.
posted by bizzyb at 11:05 AM on January 19, 2011

Can you? Maybe. Analog-to-voice mostly just works, unless it just doesn't. Magic jack sort of supports faxing so might work for other analog devices. Should you? Probably not. Would I? No.

You'd be replacing a critical security device (POTS hardline - high availability/known features) with a home-brew "system" that has multiple points of failure. You need to better understand the risks involved to be able to weigh those risks vs. the $40 a month cost.

What risks? What if the power drops? Most alarms have batteries and phone lines are powered. All your pieces need to be powered. How long is the UPS power going to last? Do you mind if it drops after ~15 minutes or need to keep it on until the power is back on? Who is your VoIP provider? What's their SLA for uptime and availability? What if your PC or your router fails? How long till you get a replacement? Or if comcast drops service for a day? Etc..
posted by anti social order at 11:09 AM on January 19, 2011

Switch alarm services? Brinks ( now called Broadview ADT) could probably make the switch easily enough. My system only requires one phone line. They also offer a Radio based service in certain areas.
posted by Gungho at 12:36 PM on January 19, 2011

Can you switch to hardware that uses a SIM card instead, sending the information over the cellular network? No line to cut either.
posted by defcom1 at 2:41 PM on January 19, 2011

Your goal is clear - but it is hard to determine whether you need two POTS lines for other purposes that the alarm system is utilizing, and what you are paying for monitoring vs. the phone line each month.

The way I read your question: $20 per line and you are paying currently a total of $40/month on lines that you'd like to eliminate one of the two lines to VOIP (and save $20) but you do not indicate what you are paying for monitoring service.

I looked into these options for a while - and a DIY option is much more flexible than the upselling security companies that charge $35 or $40/month for a service that can cost on the order of $9 or $10/month instead. (NextAlarm has a service at $9/month if prepaid for 1 year; if you'd like to combine this with VOIP this thread on DSL Reports will be useful. Alarm Relay is another option for lower-cost monitoring.

But it presupposes you own your own system, which may or may not be the case with the way alarm companies currently do business (and write fine-print contracts).

If you are on a 'month-to-month' basis, you can choose whatever monitoring you want, and make changes to your own system or change it out altogether. I agree with anti social order above that ethernet reliability is something else to worry about, but that there are systems available (see the home security store for details) that can notify your alarm provider via an Ethernet connection.

Of course other points of failure include protecting your house from a burglar cutting the phone connection (home alarms also can come with a cellular connection backup system), so there are lots of things to think about....

The way I've gone? DIY wireless alarm with a remote siren (disabling the 'all-in-one' unit's siren in favor of a remote siren so that the would-be-thief cannot track down the main control unit), and have gone with a FiOS voice system for the landline that works fine.
posted by scooterdog at 8:44 PM on January 19, 2011