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In the US too - the reasoning is that it's simple and should work in a power outage as the telephone company usually can power it from the central office. Conve

In the US too - the reasoning is that it's simple and should work in a power outage as the telephone company usually can power it from the central office. Conversely, VoIP would depend on too many technologies working well to be reliable enough for emergency use.

superuser2 10y ago
I've definitely seen elevator phones attached to the PBX with VoIP trunking, but all the components were on battery backups.
- jlgaddis 10y ago
  At a previous employer (large .edu), we moved to VoIP several years ago but keep several PSTN lines -- including all of the emergency ones, such as for the elevator. We could have moved them to VoIP as well but we figured, in a true emergency, it was one less thing to have to worry about.
  - godzillabrennus 10y ago
    In Chicago building codes mandate elevators have a pstn line in place. Even luxury homes with small elevators.
    - hexane360 10y ago
      Well, I mean people have died from being stuck in their own elevators: http://www.cbsnews.com/news/elderly-couple-dies-trapped-in-home-elevator/ http://www.cbsnews.com/news/elderly-couple-dies-trapped-in-h...
    - walrus01 10y ago
      Most large cities' building codes mandate auto-start/auto-transfer backup generators for elevators in buildings over a certain height. It is sometimes possible to put critical equipment on a generator backed circuit (such as a 48-port 802.3af PoE switch providing power to phones).
- walrus01 10y ago
  This can be harder to do than it looks at first glance - the electrical cable "snake" that follows elevators up and down their shaft is frequently implemented with only POTS/cat3 grade wiring. Getting a SIP phone to work in one can require a local source of power in the elevator (usually a 120VAC to 12VDC power supply for the phone rather than PoE) and a VDSL2 bridge for 100BaseTX over the old style phone wiring.
  - superuser2 10y ago
    Right, I'm talking about a plain analog phone connected to one of the ATAs on a Cisco PBX. I was doing some other work on the rack and remember a cable flag that said "ELEVATOR" :).
jcrawfordor 10y ago
An interesting thing to think about in elevators is who exactly the elevator phone calls, as well. In large buildings it sometimes rings a location staffed 24/7, like a security desk. In most buildings, though, for better reliability the phone actually rings a dedicated outside answering service for elevator phones. Sometimes this is provided by the manufacturer of the elevator as part of an "all-inclusive" service package, and sometimes they're hired by the property manager, but in a lot of cases the elevator company that does the maintenance programs the elevator phones to call their contracted answering service so as to ensure that they'll be the ones sent out to do the repairs. It's a bit like the plumber leaving you a fridge magnet with their 24/7 line.
- kalleboo 10y ago
  Yeah, I got stuck in the elevator in my apartment building and had to use the phone, it went to the local Otis service line.

superuser2 10y ago

I've definitely seen elevator phones attached to the PBX with VoIP trunking, but all the components were on battery backups.

jlgaddis 10y ago
At a previous employer (large .edu), we moved to VoIP several years ago but keep several PSTN lines -- including all of the emergency ones, such as for the elevator. We could have moved them to VoIP as well but we figured, in a true emergency, it was one less thing to have to worry about.
- godzillabrennus 10y ago
  In Chicago building codes mandate elevators have a pstn line in place. Even luxury homes with small elevators.
  - hexane360 10y ago
    Well, I mean people have died from being stuck in their own elevators: http://www.cbsnews.com/news/elderly-couple-dies-trapped-in-home-elevator/ http://www.cbsnews.com/news/elderly-couple-dies-trapped-in-h...
  - walrus01 10y ago
    Most large cities' building codes mandate auto-start/auto-transfer backup generators for elevators in buildings over a certain height. It is sometimes possible to put critical equipment on a generator backed circuit (such as a 48-port 802.3af PoE switch providing power to phones).
walrus01 10y ago
This can be harder to do than it looks at first glance - the electrical cable "snake" that follows elevators up and down their shaft is frequently implemented with only POTS/cat3 grade wiring. Getting a SIP phone to work in one can require a local source of power in the elevator (usually a 120VAC to 12VDC power supply for the phone rather than PoE) and a VDSL2 bridge for 100BaseTX over the old style phone wiring.
- superuser2 10y ago
  Right, I'm talking about a plain analog phone connected to one of the ATAs on a Cisco PBX. I was doing some other work on the rack and remember a cable flag that said "ELEVATOR" :).

jcrawfordor 10y ago

An interesting thing to think about in elevators is who exactly the elevator phone calls, as well. In large buildings it sometimes rings a location staffed 24/7, like a security desk. In most buildings, though, for better reliability the phone actually rings a dedicated outside answering service for elevator phones. Sometimes this is provided by the manufacturer of the elevator as part of an "all-inclusive" service package, and sometimes they're hired by the property manager, but in a lot of cases the elevator company that does the maintenance programs the elevator phones to call their contracted answering service so as to ensure that they'll be the ones sent out to do the repairs. It's a bit like the plumber leaving you a fridge magnet with their 24/7 line.

kalleboo 10y ago
Yeah, I got stuck in the elevator in my apartment building and had to use the phone, it went to the local Otis service line.