Verizon Call Intercept

["Roland Postle" <mail () blazde co uk>]

The Call Intercept service from Verizon (and possibly others) is supposed to
screen callers that withhold their callerid or don't have one because
they're out of area etc.... A recorded voice invites them to leave their
name, then puts them on hold while it contacts the number with call
intercept. They either accept the call or they don't.
(http://www22.verizon.com/ForYourHome/SAS/ProdDesc.asp?id=6063&state=NJ for
more details).

It's designed to counter the telesales people that delibrately withold their
callerid so you pick up but some relatives of mine have the service to block
harassing calls. Typically they'll get 20 harassing calls in one night. But,
when it was put to the test one night some (about 1 in 5) calls made it
through to their answerphone without being accepted. Sometimes they get
other international calls that get straight through too.

The (human) problem seems to be that in the UK we don't have a 'pound key'
(well we do but it's called 'hash'), so UK callers are pressing the star and
number keys as well as hash when the recorded voice tells them to press the
'pound key'. I figured the problem could be related to the different key
tones we have in the UK. (Which leads me onto a sub-question probably not
really relevant to this list, how is the tone translation on international
calls handled?) Anyways, it's not that because I've replicated the problem
from another (local) US line, a bit of button bashing sometimes works, but I
can't narrow it down anymore than that. It's not through accidentaly typing
in the four digit PIN (which would be unlikely anyway) or else the ring tone
would be different.

The description for Call Intercept (at the above URL) isn't totally clear on
whether a caller that records their name, doesn't have the PIN, and who's
call isn't answered should be allowed to leave an answephone message or not.
At first glance I don't know how they'd implement that since it would
involve reliably distinguishing whether an answerphone or a real person
picked up the call. However, in my experience often they won't be able to,
and although most of the times I've seen people break through the intercept
it's been picked up by an answerphone it's also happened when a call's been
answered by a real person.

So either I've completely misunderstood what the service is supposed to
achieve or there's some kind of fault, possibly an intentional override code
for technicians, or a backdoor left for use by telesales companies that
Verizon 'likes'. It's probably irrelevant but Verizon aren't allowed to
offer the service to people unless they initiate an interest in being able
to screen calls. Presumably some pro-advertising law.

(Apologies for the long post)

- Blazde