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Old July 21st 18, 12:33 AM posted to alt.windows7.general
VanguardLH[_2_]
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Posts: 10,881
Default telephone hackers - can we upload something?

J. P. Gilliver (John) wrote:

In message , Ed Cryer
writes:
[]
There's some way of keeping a telephone line open even when the number
called hangs up.
I've been on the receiving end of this from a spam auto-caller. It
calls, I answer, it starts telling me how fabulous it's company's
product is, I hang up, wait ten seconds, pick up phone, and the thing's
still droning on; and it does that until it's finished its little lecture.
How do they do that?

Ed

(This applies here in UK - probably there as well.) If only one party
hangs up, the connection remains open - for a time. I presume it's to
prevent _accidental_ termination of a call due to noise on the line, or
similar. (It _can_ even be useful - lets you hang up one 'phone and pick
up another, say if one handset's battery runs out, or you want to go to
another one next to your desk or something.) It _does_ time out
eventually, but after quite a lot of seconds. Banging on the rest
_sometimes_ clears it.

Unfortunately, it's well known to be misused by evil folk: they'll ring
up pretending to be your bank or whatever, then suggest you hang up and
call the bank using a number _you_ choose. Unfortunately, they keep the
line open - even playing you a recording of the dial tone when you hang
up and pick up again, so you _think_ you're genuinely dialling.

Because of this, I think there are moves in place to force the
telecomm.s companies to prevent it, mainly I think by shortening the
timeout-on-one-party-hangup. In the meantime, the advice is - should you
receive such a call apparently from your bank, though this is unlikely -
that tells you to call them back, to first call some unrelated number,
such as a relative.


https://www.niceincontact.com/blog/c...ts-home-agent/

CCD is a throwback to the old days of mechanical switches at the phone
exchanges. Some PSTNs will disconnect an idle call after 2 minutes.
You'd have to ask yours how long they keep a call connected when one of
the parties has hung up on their end.
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