911, was You're all over thinking this (was: Re: Vonage Selects TCS For VoIP E911 Service)

Mon Jul 25 09:55:43 UTC 2005

John Levine <johnl at iecc.com> wrote:
[...]
> Given that we're talking about cell phones, it seems completely
> likely. Cell phones present the dialed number as a block, so there's
> no ambiguity between 911 and 911XXXXX. I don't know whether UK cell
> carriers map 911 to 112, but there's no technical reason they can't
> do so.

If people expect 911 to work on mobile phones, they will also expect
it to work on the PSTN.

<rant> And why should the UK change its numbering system just because
a few dumb Yanks who can't be bothered to learn local customs? Does
999 get through to the emergency services in the NANP? Does 112 work
on non-GSM phones? How about Australia's 000? </rant>

> I agree that for VoIP using normal phones through adapters, 911 in
> the UK won't work.

ATAs usually collect digits to send as a block as well, either with
the user explicitly dialling # after the number, or implicitly after a
timeout. At least that's what I see with Cisco ATA-186, 7940 and 7960
and the Sipura 2000 I've tested.

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