VoIP for emergency communications

Discussion in 'Networking, Telephony & Internet' started by Symon, Oct 13, 2015.

  1. Symon

    Symon Castigat ridendo mores

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    I did a search and couldn't find anything, so apologies if this has been asked before.

    I'm working for a large underground mine and we are looking to upgrade our communications infrastructure, and the consultant has put forward a VoIP solution over WiFi as well as fixed phones from fibre/Cat6. So far, so good.

    However they have also proposed the same for emergency locations such as refuge chambers. Traditionally we have used POTS systems for these (powered from the surface) so that we can communicate with the teams underground should things turn sour. My concern with the VoIP solution is obviously the switches need to be powered for it to operate, and there is only so much UPS autonomy we can have underground.

    So my question is - is it normal for VoIP to be used for emergency communications? Am I being over cautious here?
     
  2. Gaidin

    Gaidin Member

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    I can't add any expertise here...but just wanted to say that I don't think you're being overcautious at all. Very valid questions I think :thumbup::thumbup:
     
  3. bcann

    bcann Member

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    I assume its not a coal mine as I thought they didn't allow wireless type devices in the underground (I worked aboveground in coal) but I might be wrong here.

    I would assume that you are mains powered underground and have UPS's connected to critical gear (POE Switches and critical other gear). I would also assume that you have procedures in place to evacuate the underground should mains power stop as I imagine air flow will stop or be compromised in an underground environment.

    I don't see the issue. Is POTS more reliable ... yes, but it will also suffer should mains power be lost as your onsite PBX will run out of power eventually when the UPS runs out of power. If you have a genset onsite to power the site outside of the underground, why not get a smaller one and place it on a dedicated circuit to power the underground critical equipment, thus alleviating your concerns over power.

    Personally the only concern I see is wireless isn't great and something I would want to rely upon in an emergency, i'd always want a hard wired IP phone rather then a wireless one, because wireless reception can get pretty sucky and if my life depended on it, I wouldn't want to rely upon it.
     
  4. ir0nhide

    ir0nhide Member

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    VoIP is as reliable as the network it runs over. If ethernet cables are being run to an emergency location and there's a PoE phone at one end and a PoE switch at the other, how is that less reliable than POTS?

    On second thoughts, if it's more than 100M (duh, it's a mine) then yes you do need to worry about power in the remote location. Risk is if you lose power at the far end you lose comms. Business needs to decide how resilient they want the power systems to be in the emergency areas.
     
  5. heydonms

    heydonms Member

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    Get a POTS phone, and a VOIP phone, cut the cable to each, strip the wires back with your teeth and twist them together, the POTS phone might sound rubbish but it will definitely work, can you say the same for VOIP?

    POTS phones can be incredibly simple. If you only need to answer calls and not generate DTMF tones and all the other stuff modern phones do, you can build one with a speaker, a microphone and a couple of resistors, and in a pinch you could probably do without the microphone and resistors and just yell into the speaker and it would still get a signal out.

    You can even ditch the phone altogether, take the cable out of your POTS phone, strip the wires, hold the bare ends. When the phone rings (you will know when it is ringing because you are getting 90V across your fingers) take the two wires and tap them together quickly, the caller will hear the call pick up and a click each time the wires touch. As long as you don't keep them separated for too long the call will remain active. You can now indicate that you are still alive and send morse code in one direction.

    POTS doesn't require a PBX, you can connect two phones together using a car battery for power, they won't ring or have dial tone, but if both ends pick up, they can talk to each other.

    In an emergency, you want things to be simple and reliable. If you've got people stuck down there and everything possible has gone wrong, and a bunch of experts arrive, would you rather tell them "They've got a phone down there, here is the cable that runs to it" or "They've got a VOIP device, it's configured with a static IP of 192.168.4.17, unless someone didn't update the spreadsheet when they replaced the handset, the SIP login is..."?
     
  6. tobes

    tobes Member

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    I couldn't agree with this more. I work in the industry, specifically focused on VoIP for ten years and I would be leaning towards POTS for emergency comms.

    Absolutely nothing wrong with VoIP for day to day work but for absolutely must work even when it probably shouldn't stuff like a phone in an emergency bunker I have to recommend POTS.
     
  7. elvis

    elvis Old school old fool

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    Also registering interest as a casual observer. Fascinating stuff.

    I know ham radio is frequently the saviour for above-ground disasters when normal communications gets knocked out. Below ground emergency communications sound like a nightmare to try and manage. I have zero experience in the field, but I can't think of any way of getting around old school wired analogue POTS/intercom (short of tapping out Morse code on pipes).
     
  8. cvidler

    cvidler Member

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    You probably also need to look at intrinsic safe equipment (explosion proof, for use in hazardous environments).
     
  9. OP
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    Symon

    Symon Castigat ridendo mores

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    I've worked in underground coal and we do have wireless systems, they just need to be rated for the application.

    In an emergency situation it is pretty much assumed that the power supply to the underground will be lost. Primary ventilation is on the surface, only secondary ventilation is underground, so air flow will still continue on the event of underground power loss.

    POTS is powered from the surface with a pretty large battery back up. Connecting a generator supply is easy. Generator supply underground, not so.

    Again that's the problem, loss of power = no more VoIP. With POTS the supply comes from the surface.

    It is a metaliferrous mine, so no hazardous areas.
     
  10. Primüs

    Primüs Member

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    So this would be assuming the runs are too long for PoE from the surface? In which case yes, POTS would be a much better choice for these phones, but this doesn't mean it can't 'integrate' with your VoIP system, they just terminate into an ATA on the surface and power is pushed down the line for the 'dumb' phone that gets its power from the copper on the other end.
     
  11. blankpaper

    blankpaper Member

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    I work for a multinational that makes VoIP PBXes, and even we avoid VoIP like the plague wherever possible for emergency phones. The last hop in the call flow is VoIP (pretty much out of necessity) but that's got 3 or 4 levels of redundancy built in, mostly to ensure the emergency phones will work under any circumstances except for nuclear war.

    Yes VoIP will likely work fine, but do you want to risk that 1 in a thousand chance that it won't work when you reallllyyy need it to? Most people won't want that hanging over their head.
     
  12. OP
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    Symon

    Symon Castigat ridendo mores

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    >1000m, so yes.

    The ethernet link we have to the surface is via fibre.
     
  13. bcann

    bcann Member

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    My comment about the generator was that for the underground the separate generator would still be aboveground, but separate to the mains power, thus it avoids your power issue.

    As to the other poster about POTS is powered by the exchange, most companies don't bundle POTS line, they use ISDN or SIP, which connects to a PBX which needs to be powered.
     
  14. OP
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    Symon

    Symon Castigat ridendo mores

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    It would have to be a high voltage generator, the distance from surface to the first chamber is over 1500m, the one near the development face is almost 3000m. It would also mean that you need to run a dedicated power feed throughout the mine.
     
  15. Iceman

    Iceman Member

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    Er, someone has proposed a VOIP system with a run of 1.5k to 3k between points?

    Are they literally just going to run fiber with a power line next to it?

    Just go with POTS, complicating emergency systems is just asking for trouble.

    Additionally, hanging emergency systems off "general" building networks (which is feels like what they're trying to do, rather than building a dedicated, isolated system) ends up with split expectations. eg a tech thinking "it's fine that switch died at 4pm friday, no one works weekends, I'll fix it 8 am monday" - all the while they don't realize now there's a code blue alarm, a critical freezer temperature sensor, a distress call point etc that has silently lost it's ability to raise alerts to the BMS.
     
  16. Fred Nurk

    Fred Nurk Member

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    A possible comparison, if you like. IEC61850 in terms of progress from discrete wired contacts and IO to a distributed communications system capable of handling protection schemes at the communications level rather than through hard wiring.

    Certainly the equipment has come along enough to be useful, but that's without the issues that are prevalent in the mining industry, such as the 3km to the development face.

    Thus, industrial communications gear is a lot better than it used to be, you're more likely to find decent equipment to support some sort of VoIP application (say, RuggedCom rather than Cisco) but there's still enough issues around allowing for voice communications in emergency situations that it would be problematic.

    For what its worth, I'd probably still lean towards POTS, because even though IEC61850 is reliable in a substation environment, it still doesn't have the same requirement for allowing emergency human communications through. The protection equipment can be designed to handle the failure automatically.
     
  17. OP
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    Symon

    Symon Castigat ridendo mores

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    The difference is that a 61850 system will fail to safe on a loss of comms, whereas these systems are more critical, it is important that the status of those underground can be ascertained by the rescue crews on the surface.

    Looks to be that my concerns are valid, so I'll push back and say that we need to maintain the POTS system.
     
  18. ir0nhide

    ir0nhide Member

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    Sounds like a no brainer, POTS all the way for emergency comms, maybe VoIP for everything else.
     
  19. Doc-of-FC

    Doc-of-FC Member

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    surface mount a UPS with generator facilities in plant room.

    put in place something like a Cisco VG204XM / VG202XM depending on how many lines you need, those units will do:

    5 RENs per port, 12 RENs per system (maximum)
    3000 feet (about 1KM) using 26awg (I’d recommend shielded cable)
    30W power consumption, supports 100-240VAC and 12VDC (yay, solar panel + deep cycle battery backup)

    Cisco’s VG3XX range will do:
    third party call control: Time-division multiplexing (TDM) trunk: QSIG, ISDN T1 (NI, NI2, DMS-100, and 5ESS), ISDN E1 (QSIG andNET5), and T1 CAS
    IP-based trunk: SIP and H323

    Short-loop-length port 3000 ft, 26 AWG 5500 ft, and 24 AWG
    Long-loop-length port 11,000 ft, 26AWG 18,000 ft, and 24 AWG

    Ref: http://www.cisco.com/c/en/us/produc...eways/product_data_sheet09186a00801d87f6.html

    I do Voip and have experience with the Telecommunications (Emergency Call Service) Determination 2009 on 000 emergency access.

    You might not want a Cisco solution, although finding another company that'll do FXS interfacing with a SIP backhaul might be tough one.
     
  20. heydonms

    heydonms Member

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    Huh? Isn't that a description of pretty much every ATA and most hybrid-IP PBX?
     

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