A favourite trick in the UK is for scammers to stay on the line when you hang up, and play simulated noises for a dial tone and connection, then pretend to be your bank when you call the number on your card.
A trick I learned to deal with this very thing was just to attempt to call the local time/weather number after getting my dial tone back.
That said, with far-side supervision, I suspect that the call would actually time out after something like 20-30 seconds of either party hanging up. I'd just make it a habit to go put the kettle on and make some tea before placing another call.
If the call doesn't time out, well, it's time to ask BT some hard questions as to why they're allowing that sort of nuisance on their telephone network. AT&T managed to get rid of it here just fine.
> A favourite trick in the UK is for scammers to stay on the line when you hang up, and play simulated noises for a dial tone and connection, then pretend to be your bank when you call the number on your card.
Sure, but that only works for landlines. Is this still a common thing in the UK?
Most broadband "landlines" are not a real BT landline but instead one simulated by your broadband router (it's SIP on the other end). With SIP, once either you hang up or the other side hangs up the session is terminated and there is no way to recover it.
As far as I'm aware BT still have normal landlines to most areas - the phones are separate from the router, they don't go through it first and even support old pulse dial phones.
The United Kingdom phone system has what is called "far-end supervision" where the circuit-switched landline system will only disconnect the call from the receiving caller if the phone where the call originated hangs up.
This trick only works if the receiving caller is on a landline. It will not work on mobile phones.
It should disconnect eventually. And the timeframe for "eventually" has been changed in recent years.
Originally there was a grace period because of pulse dialling. Each "pulse" is actually a hangup - so the system had to tolerate that hangup != disconnect. But the grace period was far too long, and eventually end-users adopted it as a feature - if you wanted to take this on your bedroom phone instead of your hallway phone, you could hang up the phone, go up stairs, and pick up the bedroom phone.
So now we have two problems. One is that the bug has been adopted as a feature. The other is that precisely because of 999/e911 systems, the phone system is incredibly backwards compatible. Most exchanges still support pulse-dialling - it's never dropped intentionally (some exchanges don't, because they're too modernized. But it's not a conscious "lets turn this off now" thing.)
There has been a move in recent years to reduce the grace period, precisely because of this abuse. But until it's dropped short enough to be a non-issue, my advice for anyone who thinks a call is suspect, is to call the talking clock (123 in the UK). It is a paid service, but I don't like bothering the operator for such things. But if you call 123, and reach your bank, you know summat's up.
> my advice for anyone who thinks a call is suspect, is to call the talking clock (123 in the UK). [...] But if you call 123, and reach your bank, you know summat's up.
No no no no no.
Hang up and use another phone. End of. Any advice that you call another number first or whatnot is bad advice. If such advice got widespread, what would scammers do?
Obviously, they would have a DTMF decoder on the other end and they would patch the call through to the number you called. These are sophisticated people who send fake security officers to people's houses to "pick up the compromised card". Call forwarding is trivial.
Good that the UK is moving away from this "feature".
(I still remember that to take a call on another phone, you could just leave the receiver up on the phone you too the call on, provided you're not too lazy to hang it up later).
Only some phone systems in the western part of the US had far-end supervision, so far as I am aware. (This is why movies and TV shows from in and around Hollywood show conversations where the caller hangs up and the callee hears a dial-tone. The phone systems in most of California had only far-end supervision. Tom Scott has a good video on this[0].)
Most of the US uses either near-end, where the recipient hanging up will end the call, or both-end supervision, on POTS/landline systems.
0 - https://www.youtube.com/watch?v=bUIiUXvnkUQ - This video was filmed at the excellent Museum of Telecommunications in Seattle, located in a CenturyLink switching office. When travel is available again, I encourage all phone geeks to come here and check it out.
It only works in the UK where the phone call only ends after both sides hang up. The idea is you can hang up go to a different room and resume the conversation. The results are this fraud is possible.
Definitely used to be the case in Canada. The caller had to hang up: if the receiver hung up it took a (something like 20 second) timeout before the call would terminate. We did used to use that to move to another extension in our house.
Note to kids: we used to have our phones anchored to the wall with these coiled ropes so you couldn't walk away with them To counter that, we had multiple phones in various rooms of the house. They also made the phones so big the wouldn't fit in your pocket as another way to prevent stealing them. They didn't have screens because the vacuum tubes drew too much current and they would get too hot when pressed to your ear.
In Sweden both sides had to hang up, not sure how it is now. My mother used it for kids prank calling. She just left it open until the parents came home and wanted to call, then she explained that their kid had been prank calling us.
Most seniors I know have a mobile phone. How else would they be able to show off pictures of their grandkids? Also, that's how hearing aids work these days.
In the UK landlines almost always start with 01 or 02 so it's easy to identify who is using a landline. You can also go through the phone book (which only lists landlines) looking for "elderly" names. People who don't bother / know how to opt out of the phone book are probably easier targets as well.
Not both parties, the caller. And there's a timeout which these days is set to about 2 seconds. Here's the BT Openreach (the last mile provider and thus de facto the supplier of landline telephone service to almost all of the UK) write-up for when it was reduced to 10 seconds in 2014.
