Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 


Forgot your password?
Close
typodupeerror
×
The Internet Technology

VoIP and Home Security Systems Don't Get Along 187

Posted by samzenpus from the your-door-wants-you-to-stop-calling dept.
coondoggie writes "Here is a story about consumer VoIP services that can cause your home security alarm system to malfunction or not work at all. There have been problems with customer phone systems in Canada who were using Primus but Vonage customers in the U.S have complained too. A number of sites have popped up offering suggestions to help deal with the problem."
This discussion has been archived. No new comments can be posted.

VoIP and Home Security Systems Don't Get Along More

VoIP and Home Security Systems Don't Get Along

Comments Filter:
  • Here is a story about consumer VoIP services that can cause your home security alarm system to malfunction or not work at all.

    This would present quite a difficulty, if say, your home security system was ED-209.

  • Get it through your thick skulls (Score:2, Interesting)

    by Anonymous Coward
    I don't mean to be mean, but home broadband connections and VoIP services do not meet the same standards of reliability and uptime that your landline is generally required to meet.

    Whether it is 911 service or your home's alarm system, do you want to trust your home broadband connection for emergencies?

    • Re: (Score:2, Interesting)

      by X=X+0 ( 142003 )
      Yes. I do... Especially ever since my local phone provider switched my land line over to fiber to the house. So my net and phone are all on the same fiber, so I might as well use the VoIP solution and save the money.

      At least they put the fiber interface on battery backup so it works even with the power out. POTS is going away so we might as well work with it.

      BTW, the fiber has been ultra reliable. 1 year with it now and not one outage!! Yeah! :-) So much better then the cable modem.

      - X
    • the other day it was raining here - does that sometimes in florida- and my pots phone through bell south was down. so my wife had to im me at work - since our internet was still up. go figure.

    • Re: (Score:3, Interesting)

      by SeaFox ( 739806 )

      I don't mean to be mean, but home broadband connections and VoIP services do not meet the same standards of reliability and uptime that your landline is generally required to meet.

      I think the issue has to do with the actual power coming over the house wiring with VoIP-based phone versus a Baby Bell's network. When I changed my phone service from SBC over to our cable provider, the service is digital, but it's not run over the cable modem, it has it's own dedicated bandwidth. It rarely, if ever, goes down. B

      • Very possible. When a call comes down the line of a standard ILEC phone line, the voltage is ~100VAC to ring the ringers in the phones of your home. I don't believe most VoIP adapters support this sort of voltage on the phone side.

        • Re: (Score:2)

          by SeaFox ( 739806 )

          Very possible. When a call comes down the line of a standard ILEC phone line, the voltage is ~100VAC to ring the ringers in the phones of your home.

          Interesting, I knew the normal voltage was 48v, but I didn't realize this jumped so high for ringing. Although that wouldn't explain why a security system is being thrown off by it, since it would seem the system is not detecting the dial tone to start with. The system wouldn't be receiving calls.

          Most people don't seem to realize that they can't just pop as many

    • And more to the point. Do we want to rely on a home broadband connection for us to set off our alarms accidentally?

  • Bah! (Score:2, Insightful)

    by Anonymous Coward
    If you''ve got VOIP, you've got an IP network.

    Get an alarm system that uses your IP network rather than legacy POTS network.

    • Re: (Score:2, Informative)

      by Teppic_52 ( 982950 )
      Despite the leaps and bounds in IP security over the last decade or so, the physical security industry is mostly unwilling to adopt IP technology for standalone systems, such as domestic intruder alarms, mainly because of perceived 'security' issues.
      The irony is that the current security protocols would get IP/IT security professionals giggling like school girls and saying things like 'Awww, how quaint'.

  • so what else is new? (Score:3, Insightful)

    by Swave An deBwoner ( 907414 ) on Wednesday February 14, 2007 @09:07PM (#18018920)
    Depend for emergency communication on a shared bandwidth communications link whose functioning depends on utility power availability coupled with some ISP's service plan, and maybe when the bad guys break in you won't get the call? Huh? You think? Or, to put it another way, there's no guarantee that The Phone Company's own landline will work perfectly either, but if I had to bet my home on it, I'd go with TPC over VoIP. In fact, personally, I've stuck with TPC landline because of E911, because my landline has always worked during NYC blackouts even when my cellular phone didn't, and because I have yet to see a VoIP service provider that would guarantee that if some guy in Afghanistan (or Milwaukee, for that matter) somehow manages to clone my SIP identity and proceeds to make N-billion dollars (well, amounts are relative to my savings account balance) worth of international phone calls, that they won't hold my feet to the fire if I refuse to pay the bill. But of course, you may see things differently.

    • Re:so what else is new? (Score:5, Funny)

      by scottv67 ( 731709 ) on Wednesday February 14, 2007 @09:26PM (#18019094)
      ...if some guy in Afghanistan (or Milwaukee, for that matter)...

      Do not meddle in the affairs of people from Southeastern Wisconsin, for you would taste good boiled in beer and smothered in sauerkraut.

      • Re: (Score:2, Funny)

        by McNally ( 105243 )

        Do not meddle in the affairs of people from Southeastern Wisconsin, for you would taste good boiled in beer and smothered in sauerkraut.
        One Dahmerbraten coming right up!

    • Re:so what else is new? (Score:4, Interesting)

      by timeOday ( 582209 ) on Wednesday February 14, 2007 @09:26PM (#18019104)

      I had to bet my home on it, I'd go with TPC over VoIP. In fact, personally, I've stuck with TPC landline because of E911, because my landline has always worked during NYC blackouts even when my cellular phone didn't


      I dunno. Before plugging my VOIP service into my home circuit, I of course had to disconnect my home curcuit from the phone company. I can tell you it was very easy; I just opened a plastic box on the side of my house and unplugged it. If you're worried about "bad guys," a cellphone might be better.


      In type type of general emergency likely to kill cellphones (or Internet), I don't think you have great odds of contacting the police and getting a swift response anyways. You're worried about the Internet as a shared bandwidth link? Well 911 and the police are shared resources, too. I can tell you plenty of folks called 911 from the WTC, or when New Orleans flooded, and it didn't help them much.


      If you're worried about a random Internet or cellphone outage at the same time as a random burglary, go ahead, but for me personally that's on the other side of "lightning strike."

  • This one smells (Score:5, Interesting)

    by kilodelta ( 843627 ) on Wednesday February 14, 2007 @09:11PM (#18018964) Homepage
    It smells because there are easy solutions to the problems. First of all, you can supply backup power to your ATA and not have to worry.

    Secondly you should wire your setup as RJ31X so the alarm system can cut in and take control.

    Thirdly - you can set your bandwidth so that fax and modem signals will work. Better yet, how come no alarm company has an IP based monitoring setup? Be pretty simple to do with VPN's, etc.

    Finally the E-911 issue was resolved a long time ago. I have full E-911 service through Vonage.

    All this leads me to believe that ILEC's are behind these stories. They're losing business left and right to less expensive VoIP carriers. And Verizon for one is in a particularly bad spot, their little fiber build out isn't generating the returns they expected.
    • you can set your bandwidth so that fax and modem signals will work

      Doesn't this also depend on the codec used to make the call as well as bandwidth? Obviously a codec that doesn't compress data (G.711 at 64kbps) will require more bandwidth than say, G.729 at 8kbps but regardless of bandwidth, the codec needs to be correctly set on both sides too, otherwise data will be lost through compression.
      • I don't know of too many U.S. VoIP providers that *don't* support G.711u, which is your best bet for fax/modem stuff anyway.

        • Re: (Score:2)

          by Agripa ( 139780 )
          I don't know of too many U.S. VoIP providers that *don't* support G.711u, which is your best bet for fax/modem stuff anyway.

          The problem here is that older and most current analog modems and fax machines make some simplifying assumptions about the physical link which are violated by VOIP. For instance, the latency itself even if constant may exceed the length of the FIR filter used to adjust for far end crosstalk and echo.
          • For instance, the latency itself even if constant may exceed the length of the FIR filter used to adjust for far end crosstalk and echo.

            There shouldn't be any far-end crosstalk and echo since that should've been removed by the hybred. With POTS at both ends you basically have 2 places where echo can be introduced (for audio you transmit):

            1. the analogue segment on your side (your modem should remove the echo here as usual, which is simply a case of subtracting the transmitted signal from the received signa

            • Re: (Score:2)

              by Agripa ( 139780 )
              There shouldn't be any far-end crosstalk and echo since that should've been removed by the hybred. With POTS at both ends you basically have 2 places where echo can be introduced

              How long is the FIR filter used for canceling echo and crosstalk then? I have always figured it was long enough to account for effects at the far end of the POTS connection (implying an analog to digital to analog connection) and that the shorter ones used for low latency modems limited their performance on longer latency calls. A
              • How long is the FIR filter used for canceling echo and crosstalk then? I have always figured it was long enough to account for effects at the far end of the POTS connection

                I'm not familiar enough with the design of modern modems to tell you. I would imagine that they can cope with echo on the far end, but in normal conditions shouldn't need to. Even for voice communications over high latency connections you need to remove the echo wherever you go from separate rx/tx (e.g. digital) to rx/tx over the same w

                • Re: (Score:2)

                  by Agripa ( 139780 )
                  I'm not sure how low a modem will go when doing retraining. If it could keep dropping the speed all the way down to 300baud FSK then I can't see any reason why it wouldn't be able to find a (low) speed where the tollerances are great enough to make it work. However, I'm pretty sure that modems will give up long before they get down to the really low speeds (doesn't retraining only happen for speeds over about 14.4Kbps?).

                  V.32 includes retraining and fallback down to 4800 bits/s and V.22 also supports retrain
                  • I wonder how much the lack of routable endpoint addresses in IPv4 will hold back native IP systems from replacing legacy FAX, security, and other devices that currently depend on the POTS.

                    I'm certainly a big proponent of IPv6 and see peer-to-peer applications such as VoIP being a major driver for it's adoption. However, in this case I'm not convinced you need many routable endpoint addresses.

                    From a technical perspective, fax can more or less be replaced with MIME email immediately - there's no particular r

    • Re:This one smells (Score:4, Interesting)

      by Lumpy ( 12016 ) on Wednesday February 14, 2007 @10:07PM (#18019422) Homepage
      Firstly voip does NOT WORK for data modem calls. which alarms rely on.

      Secondly, alarms are mad so frigging cheap that only ONE exists that is IP ready..... That's ADI. Problem is most alarm companies cant handle such an advanced alarm and most people buying one want the $99.00 special not the $1500.00 ADI system + 1 hour programming.

      Thirdly, if the alarm buyer was not a cheapskate they would opt for the cellular connect module and forget the land line. It's another $159.99 plus and extra $5.95 a month for monitoring fees to pay for the single 1 minute call it makes every night.

      Most home alarms out there installed are utter crap. The ADT junk is incredibly outdated and horribly low quality. People want cheap fake peace of mind, they really do not want to spend real money on security.
      • Firstly voip does NOT WORK for data modem calls. which alarms rely on.

        Yes it does. You do need a very reliable network connection though. Add G.711 and QoS you should be fine.
        • No, Modem calls are not reliable with VoIP even with G.711 and QoS, even on a local LAN.

          Yes, they usually work anyways.

          Traditional circuit switched telephony (ISDN such as BRI or PRI, T1 Trunks, or any digital trunk, where the call ends up) uses synchronous timing to provide 8khz audio that is precisely timed at both ends of the connection. VoIP does not have the ability to provide a precise 8khz clock to both end points, there will always be some variation. This is compensated for by dropping and inserti
      • When I researched my home system, most of the signalling protocols predated Bell 212A. They were crude, proprietary, and ran at speeds measured in tens of characters per second. Anything that slow ought to be robust.

        Alarm monitoring sold as VOIP compatible [tmcnet.com], I haven't tried it.
      • Most home alarms out there installed are utter crap.

        First of all, in the event of a break in, the police will show up about half an hour too late. They don't care, because you should have insurance. They know there's more important things to do like bust serious crimes.

        Second of all, if I have an alarm and have made it clear by posting signs all over my house that I'm alarmed, the thief will move onto the next home that doesn't have one anyway.

        Honestly, I could give a rat's ass if my alarm is top qualit

        • Re: (Score:3, Insightful)

          by ivan256 ( 17499 )
          They know there's more important things to do like bust serious crimes.

          If you're in the suburbs (30 cops in one town, one non-domestic violence crime in the last five years) that should read:

          They know there's more important things to do, like generate ticket revenue.

        • Re: (Score:3, Insightful)

          by ivan256 ( 17499 )
          Oh, I forgot one more thing:

          Honestly, I could give a rat's ass if my alarm is top quality, I have it because I get a break on my home insurance, not because I feel safer when I go out.

          There's nothing like the piece of mind that comes from knowing that if you forget to set your alarm and you get robbed your insurance company won't pay the claim...
          • You should look into switching your insurance carrier. The vast majority will pay even if you forget to set your alarm.

            Contrary to popular myth, insurance companies don't spend every last waking moment trying to find a way to screw you out of your coverage based on some technicality. You only hear about the (rare) coverage denials, you never hear about the other thousand claims paid out to some moron who fell asleep while cooking, smoking in bed, or leaving the tub running because an important play happened

      • Re: (Score:2)

        by ivan256 ( 17499 )
        Thirdly, if the alarm buyer was not a cheapskate [...]

        Funny you'd say that about an industry that keeps the prices high through price fixing, collusion amongst distributors, and secrecy instead of through the introduction of new technology ("futuristic" technology that doesn't work isn't the same thing as new technology).

        Keep in mind what you can get for "$99" in terms of what it can do on a network. Go walk down the wireless router isle at your local computer store to see devices 1000x more complex than yo
    • As a former alarm installer, all I can say is that alarm companies don't control the hardware, they only install it. Also, alarm equipment tends to lag behind current technology. Most alarms company receivers (the ones that receive the call and translate the DTMF or other coding scheme to an alarm code for the operator) run on Z-80 processors. Not that mature technology is bad, or that Z-80 processors are bad, but the alarm equipment manufacturers like to pick technology and stick with it.
      • I forgot about the Z80 being one of the more popular CPU's for alarm systems. But even then, you could make an IP stack for a Z80.

    • Re: (Score:3, Informative)

      by kybred ( 795293 )

      Better yet, how come no alarm company has an IP based monitoring setup?

      You mean like this? [nextalarm.com]

    • Re: (Score:2)

      by JimBobJoe ( 2758 )
      It smells because there are easy solutions to the problems.

      I agree, I had VOIP put into my parent's home, and we got the alarm system to operate with it fine. The cable company's main concern was that the alarm system was a newer model and can dial via tone dialing (apparently there are a lot of old ones in the wild that only do pulse, which is incompatible with VOIP.)

      The VOIP router has its own 8 hour battery backup, so electrical problems aren't so much a concern. And the installer had it set so that the
    • First of all, you can supply backup power to your ATA and not have to worry.

      And when the power is out for the whole street, who is going to power the cable TV line amplifier? In many locals, the cable TV goes out with the power. Most people don't notice because they don't have power to turn on the TV. A few people who power their own adaptor have found out the hard way that when the power goes out, often the TV and Internet signals are down with it. DSL consumers are generaly better off in this regard,
      • Oh yeah, and did I mention that if you have copper loop from the ILEC it doesn't necessarily mean you've got a solid pair back to to the central office.

        Many SLC's don't have backup power, and pair gain devices fail when power goes out too.

        As to ILEC's being 5 9's or 3 9's that's almost bullshit. What was it that accounting professor used to see, numbers don't lie but figures do.

  • Simple answer: Basic analog dialtone (Score:3, Informative)

    by Marxist Hacker 42 ( 638312 ) * <seebert42@gmail.com> on Wednesday February 14, 2007 @09:12PM (#18018970) Homepage Journal
    To a single number. And hope that your security system HAS a local call-in number (it should anyway). The neat thing is, old fashioned phone lines are self powered and always work; you can get a dialtone that will only work with 911, 0, and a designated number for as little as $12/month in some cities. You can get 911 and 0 for free in most phone companies in the nation, this is called "basic dialtone service".
    • you can get a dialtone that will only work with 911, 0, and a designated number for as little as $12/month in some cities

      Before taxes & fees. I have a bare-minimum POTS line here at home (BellSouth refuses to sell dry DSL), which ostensibly is supposed to be $12.85/month, but somehow magically ends up being about twice that after BellSouth is done with it. :-)
      • Like I said- some cities have this, some don't....and some phone companies claim to have it and then use it as a cost center....myself, I went a different direction. I went ahead with normal phone service on top of my DSL. It's more expensive, but at least if the local cell tower is down I can still make a normal phone call (albeit from the bathroom if the power is out- all the other phones are wireless and if their base stations don't have power, they can't be used).
  • I have to say that most people I have seen do not put a UPS on their DSL or cable modem. So all the "bad guy" has to do is turn off the house breaker and then no call out. Sorta silly. The POTS service would stay on and since alarm systems have a battery, they work. But no call goes out if your broadband is turned off or your router has no power.

    • Re: (Score:3, Interesting)

      by Belial6 ( 794905 )
      Most houses have access to the POTS from the outside. It is just as easy for the "bad guy" to snip the POTS line as it is for them to shut off the power. Given that batteries on alarm systems are well known, it seems more likely that the "bad guy" would go the route of snipping phone lines over cutting power. Of course if the alarm is set to call over VOIP, or even as a TCP/IP, the "bad guy" would have to worry about cutting the phone line, the cable line, AND knocking the satellite dish out of alignment
      • Well, if it's that simple, it's not an alarm system I'd want to use.

        Any alarm should be set as a "report OK" system, where any failure to report is seen as an alarm. Even in a dial in system, it should do the same. Report in every 5 mins perhaps?

  • Surprised? (Score:4, Interesting)

    by evilviper ( 135110 ) on Wednesday February 14, 2007 @09:15PM (#18019008) Journal
    Is anyone (here) surprised by this? It seems painfully obvious to me, that most such services obviously wouldn't work. That this guy wasn't notified BY THE SECURITY SERVICE that his alarm system wasn't functioning for over a year, speaks volumes about how useless that service really is.

    It's only too easy to cut a POTS line, or tie it up by dialing-in to it, which is exactly what any competent burglar will do... Maybe with a (pre-paid?) cell-based service, your alarm will have a fighting chance, but not a lot even then.

    • Re: (Score:3, Interesting)

      by Rakishi ( 759894 )
      Happened at work once, security system was accidentally disabled (its phone line was unplugged and plugged back in, the thing didn't reconnect or something). I think it took them a few days to call back or it may have been us who called them first, not sure. Either way, if someone had done this on purpose the system would have done us jack shit worth of good.

      Honestly I'm amazed that security systems don't assume a disconnect of over x minutes should result in some sort of immediate response. I mean, if cutt

    • Re: (Score:2)

      by hurfy ( 735314 )
      And if you read the instructions i am sure they say to test it every week or some other way too often time frame to cover their ass ;)

      While the times they suggest are crazy, so is less than once a year!

      Regardless of VOIP or whatever the wire from the alarm could come loose or something, there is a reason they have a test procedure.

      I always worried about someone cutting the phone lines too but the cel phone backup to detect a cut line was way too spendy.

      PS. One bonus of being the techie at work is that i am

    • Is anyone (here) surprised by this? It seems painfully obvious to me, that most such services obviously wouldn't work.

      My home phone service is through AT&T CallVantage VoIP. AT&T has a FAQ [att.com] on its CallVantage information pages specifically about this issue. And I quote:

      No, this service does not support home alarm or security systems.

      What's more, I seem to remember I was shown this information during the sign-up process and had to acknowledge on a terms-of-service agreement form that I understo

    • Re: (Score:3, Insightful)

      by Beryllium Sphere(tm) ( 193358 )
      >It's only too easy to cut a POTS line, or tie it up by dialing-in to it, which is exactly what any competent burglar will do.

      In movies, and in some cities. Check with your local PD's crime prevention officer about trends in your area.

      Random burglars do have the option of moving on to the house next door that doesn't have an alarm system at all, saving the precious seconds to locate and cut the line. Targeted attacks are rare and quite difficult to handle.

    • Re: (Score:2)

      by rew ( 6140 )
      Dialing in? The alarm cuts any ongoing conversation, hangs up, and then dials the central alarm service.

      • The alarm cuts any ongoing conversation, hangs up, and then dials the central alarm service.

        Yes, but it has to do that faster than the dial-in system can reconnect.

  • Wireless monitoring... (Score:5, Interesting)

    by spiritraveller ( 641174 ) on Wednesday February 14, 2007 @09:18PM (#18019026)
    works great, doesn't require any phone line, and has gone down in price recently.

    POTS lines are no longer needed.
  • Places like NextAlarm.com [nextalarm.com] do broadband alarm monitoring. They also say that they can help you modify your current alarm system to let it be monitored over broadband.

    Caveat: some of their links were broken the last time I checked. Makes you wonder.

    Obligatory disclaimer: I've just hit their website looking for a similar solution; not a customer (yet).

    DT

  • Much better than a flaccid firm (Score:3, Funny)

    by sharkey ( 16670 ) on Wednesday February 14, 2007 @09:49PM (#18019302)

    According to the Allied Fire & Security firm firm

    I ALWAYS want my firms to be firm.

  • The main problem is your security system contains a modem which is plugged into a VoIP adapter which encodes and decodes the analog signals on both ends of the connection, potentially distorting the communications.

    Well, what about plugging the alarm system directly into the internet, bypassing the VoIP link? This might allow even MORE reliable communications between the alarm and the monitoring station than the phone line link would be.
  • Mr. Smith & Mr. Wesson and by Mr. Avtomat Kalashnikova
    And is backed up by two German Shepherds.

    No problems here.
    • Your dog wants steak.
      • Heh.. My dogs are trained not to eat *anything* without my approval.
        Ever seen a movie where some evil bad guy has two scary looking dogs, he places a steak in front of each one then sits down to eat his steak, after taking a bite he snaps his fingers and the dogs wolf down their steaks?
        My dogs are trained like that. They will NOT touch food or water until I tell them to.

        I have no worries about someone trying to slip them something. Besides, they live indoors with me, when they go outside I stay with them

    • Re: (Score:2)

      by vadim_t ( 324782 )
      A bit pedantic here:
      Kalashnikov is the guy who came up with it, but "Avtomat" isn't part of his name, it means "machinegun" in this instance. So the name would stand for "Kalashnikov's machinegun"
    • ... one cubic meter of bluff backed by a trained, testicle-eating fruit bat. Oh, and by having a shabbier looking house than my neighbor. What I really need, though, is an old, oil-dripping Harley ratbike chained to the front gate. That way they'll never guess I couldn't bench-press a yawn if I were soaked in sterioids, or that all my weapons are made out of pixels.

      Security? HAH! Couple of fireballs & a weapon proc will fix them...

    • >No problems here.

      Unless you have a fire when you're not at home.
  • Has anyone ever stopped to consider just how incredibly stupid this is? You're converting a digital signal to analog via a very slow modem over a simulated voice line running over a much faster digital network.

    Fax machines would have to be the most redundant technology since the floppy. Why isn't there an IP transmission option for faxes?

    • Re: (Score:2)

      by karnal ( 22275 )
      Careful, you're showing your age young whippersnapper! When I was your age, I was lucky to have a cordless phone!

    • Re: (Score:2)

      by thule ( 9041 )
      Why isn't there an IP transmission option for faxes?

      I guess T.38 is the closest to this. It is a protocol that converts fax signals to IP data and back to fax signals again. :)
      • Unfortunately it takes more expensive peripheral equipment and/or more software to make it happen, at both your end and your VoIP provider's VoIP/POTS bridge. (Your VoIP dongle/software needs to be a smartmodem, not just an A/D converter, for starters. But the POTS bridge equipment is probably a bigger cost boost for the ISP. Your provider is stuck in cutthroat competition with other providers and doesn't need to quadruple the price of his equipment to handle something that only occurs rarely and wasn't
    • Why isn't there an IP transmission option for faxes?

      Probably because of e-mail having made paper faxes about 98% obsolete so nobody bothered to promote with any vigor, any form of ip-enabled fax transmission protocol so there never has been any serious enough demand for it to come into common use.
    • Hello PDFs via email
  • Vonage was upfront about this when I got their service. It shouldn't
    be a surprise -- and it only affects those alarm services that use
    copper to monitor the system. If your alarm system is independent of
    the phone lines (i.e., doesn't need Daddy watching it all the time) there
    is no problem.
  • In Canada they just launched this service [bellhomemonitoring.ca] which uses the 1X network to monitor your home. It's much more advanced than classic alarm system because you can also self-monitor over the Internet, get paged/IM's/texted/emailed when something happens in the house etc. It also supports motion activated cameras that send pictures to your web account. I'm sure a similar service must exist in the US. Bottom line is this will work even if you're on VoIP... Oh, and no I'm not affiliated with them, I just thought

  • Dealt with this before... (Score:3, Interesting)

    by rayvd ( 155635 ) on Wednesday February 14, 2007 @11:26PM (#18019910) Homepage Journal
    Used to work at an ISP that did VoIP (wirelessly in fact). If you could tweak the baud rate on your security system and drop it down to say 1200bps, it would typically work. It was still fairly hit and miss though. Add to that that many customers had no clue how to do this and alarm companies didn't care enough to try and help them.

    Modem-type communications expect timing to be near exact (something the PSTN can guarantee) and just don't work well with the random delays (caused by 'net conditions, jitter buffering, etc) that are inherent with VoIP. T38 helps with faxing, but any sort of modem connection is going to cause problems.

    We made sure our customers knew that burglar alarms were _not_ something we supported over VoIP. In fact it's a downright silly idea tying your home protection in with your Internet connection in most cases anyways. You can often get a phone line specifically for burglar alarms for less than you'd pay for a line used for talking on as well, so this is typically what we'd advise customers to do.

  • Alarm systems used to use a separate solid copper connection between the premises and the alarm service. The better systems sent a continuous psuedorandom code sequence, constantly reporting "OK here"; anything that interrupted the connection raised an alarm. US telcos stopped offering solid copper connections because people were ordering those and using them for high-speed digital connections.

    There used to be "data under voice" services, which provided a very low bitrate channel in a narrow band below

  • Pure FUD (Score:3, Informative)

    by SpaFF ( 18764 ) on Thursday February 15, 2007 @12:11AM (#18020138) Homepage
    Vonage works just fine with my alarm system. The only thing I had to do to make it work was have the alarm technician set the system to dial *99 first in order to put the vonage ATA into "fax mode". This is supposedly needed to make vonage lines work with TIVO also.

    Obviously the author of the article (and the submitter) didn't do their homework.
    A great place to start looking for how to make your alarm work with Vonage can be found here [vonage-forum.com]

    And as for the people posting that using VOIP for an alarm is foolish because all a thief would have to do is cut the power: A thief is more likely to cut the phone line going from the PSTN to your house than he is the power. He isn't going to think, "Hmm, this person might have VOIP. I'd better cut the power, the cable, and the phone line outside the house just in case".
    • Thieves don't take the time to cut anything. They just break in steal stuff and leave. If you've got a full alarm with cameras etc, you'd need to have a priceless work of art to get the attention of thief who would try to get around your alarm. Any other thief will just look for easier pickings.
  • It's not "Any Damn Device You Can Plug Into A Phone Jack over IP".

  • It's a common misconception (even among VOIP providers) that you can run modem conversations over VOIP lines. You cannot. Modems rely on a statically behaving line quality. VOIP, by design, will have changing echo, changing line delays (very disturbing for a modem) and even changing sound quality. This will annoy your modem, even at lower baud rates. I've seen setups where even 9600 baud fax receiving would not work, while codec (711u), echo cancellation (off), jitter buffer (low, medium, high, very high),
  • When the alarm communicates with your local security company central over a normal phone line, it does so using a modem-like device. So with VoIP, you send digital data through a modem through a VoIP line, that will be sent through ADSL or a broadband modem, through a cable intended for analog data. Of course it's less than ideal. A simple bittorrent download is all you need to make sure your phone line doesn't work (or loss of power, or random glitch in any of the components down the line, such as router,
  • VOIP requires a connection to an IP network. Even those offered by cable co's that don't actually send the voice service over the public internet require an IP network, and that means the customer needs electrical power and their connection device to be plugged in and online for them to have dial tone.

    VOIP will always be less than ideal for this reason. Anything from a dog biting through the coax line to the cleaning lady not connecting things back correctly can knock out your dial tone(I've had both situ
  • Aside from the malfunctioning issue, a VOIP line hooked into a security system is not all bad. Consider this, I have my VOIP router, cable modem, and security system on a UPS so if power goes out, the system stays up and I can still make calls (obviously, if the power outage goes beyond the local level the cable would be out). Now, if a would be thief were to target my house, he/she might think "hey, this guy has a security system, I had better cut the phone line and the power. In this case my alarm woul
  • Analog phone lines, referred to as POTS lines (Plain Old Telephone Service) get converted to digital lines at the Central Office. The CODEC they use is G.711 which converts the analog to digital bits with *no* compression and each voice channel takes up 56kb/s of bandwidth (64kb w/overhead).

    The problem we had in the early 90's in setting up VoIP was with fax machines and modems. For voice calls, we could use the G.729a CODEC (which uses 12kb/s) and the customer wouldn't notice any discernible change in voic
  • If you have a Primus VoIP line and you plan to hook up a security system, fax machine, tivo, satellite dish, or anything else that uses a modem to it there are 2 things you can do to avoid most of these problems, #1 get a UPS for your cable/dsl modem and the the VoIP box so power interruptions are not an issue until they are LONG interruptions. #2 call Primus and tell them you want to use a fax on that line so they change the codec to one that eats up more internet bandwidth but gives quality sufficient to

Slashdot Top Deals

BLISS is ignorance.

Close