TELECOM Digest OnLine - Sorted: PSAPs and CNID blocks, was: New Technology Poses 911 Peril VOIP

PSAPs and CNID blocks, was: New Technology Poses 911 Peril VOIP

Danny Burstein (
Thu, 21 Apr 2005 23:02:36 UTC

( PSAP = Public Safety Answerin Position = the 911 center )

[ lots snipped ]

In <> Justin Time
<> writes:

> to access their database, except that they don't want to be bothered.

> The point is that CID can be blocked and is not guaranteed to be
> delivered. The ANI information the 911 centers use is pretty much the
> same data that feeds the telephone company billing system. That
> information cannot be blocked or opted out of providing. Of course,
> if you want the PSAP to use CID information to take emergency calls on
> a non-emergency number and do the look-up from the CID it would be
> permissible to have the PSAP lines configured for Anonymous Call
> Rejection which would reject all calls that didn't have CID. That
> would insure the PSAP had at least some information to work with.

If you're a registered PSAP you can get the local telco to provide you
with the Caller ID info, even if blocked.

Keep in mind that the caller id number is passed all the way from your
local central office to the destination CO. It's only at that last
location, immediately preceeding the "final loop", that the number is
replaced with a "not available" notation.

So if you're approved, the final CO will, indeed, pass it along.

Similarly, if you've got a facility that's considered, for want of a
better term, "close enough", you can get the same exemption. For
example, back in 2001 a group of universities and hospitals called
"Insight 100" (since many of them used the Northern Telecom switch of
the same name) requested this from the FCC so they could better assist
callers to their emergency rooms.

(FCC Docket 91-281, file # NSD-L-01-153)

After the usual bit of paperwork delay (not too bad, considering), and
a bunch of comments from the public (including me), the FCC granted
them this waiver.

Other groups that are covered would be (in many areas of the country)
your local volunteer ambulance or fire company, many of which are
reached through a direct-dial seven (ten) digit call.

And yes, CNID is not as reliable as the more specific 911 database,
but it's far better than nothing.

Knowledge may be power, but communications is the key
[to foil spammers, my address has been double rot-13 encoded]

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