FCC To Require 911 for VoIP

David Lesher wb8foz at nrk.com
Mon May 2 03:56:50 UTC 2005


Speaking on Deep Background, the Press Secretary whispered:
> 
> > Here's one vendor: http://www.tonecommander.com/e911/How%20PBX%20ANI-LINK%20Works.htm
> 
> I think this scheme isn't going to work for VOIP. 

Well, yea.. It's not.

> I think that VOIP phones will either ultimately be exempted, or required
> to have GPS (or triangulation or some other scheme)

...that might work....sometimes...

> Or maybe we'll just start to see red phones next to the fire-alarm boxes.

Alas, Gamewell fire boxes are all but dead. I don't know of any
city still running them. Too bad, because it was a dirt-simple
technology that Just Plain Worked. Looks like they were first
deployed in the 1850's.

Oops; NYC may still have some:
http://www.forgotten-ny.com/STREET%20SCENES/Fire%20Alarms%20page/Alarms.html.
And if http://plaws.net/fire/list.shtml is accurate, much of
Mass. Hmm.

OT explantion: There was a loop from the fire alarm office around
the city {or fraction thereof}, through each box, and back to
the office. One end had +130v {or so}; the other had -130.

When you pulled a box, it split the loop in half, and grounded
both halves in a sequence set on a spring-driven wheel ("3 2 5
PAUSE 3 2 5"). Think of that as the static IP address...

At the office, 2 pen registers recorded the loop current.

If two boxes (say 325 and 326) got pulled; 325 showed on the
one chart, 326 on the other.

We might have them still in wide use today if not for social
changes; the false-alarm rate is many times higher than voice
calls, and most departments gave up.

I think there are NANOG lessons in there. Sometimes, a less than
100% optimal technology is good enough to outlast many a "newer
better faster sexier" one... 


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