At 8:11PM the bells tinkle every night?

[Cruisin Marine]

I have a vintage phone (a Post Office 312L) and notice that the bells tinkle once at 8:11pm and once again at about 15-20 seconds later?
It happens at weekends too.
It only happens once a day- does anyone know why?

[paulsherwin]

It's likely to be some sort of Openreach automated line test.

My parents used to get a chirp from their phone at about 11pm every night.

[G6Tanuki]

Yes it is a generic line probe from BT or OpenReach or whoever the circuit provider is. My parents used to get worried by these 'pings', thinking that someone was trying to call them and they had missed the call.

Despite my reassurance that it was just a test that the phone is working they would call 1471 to find out who it was that was trying to call, then call me to ask what was happening.

Most annoying. I never did get them to move to using mobiles, which would have been free of this nonsense and cheaper too.

[Cruisin Marine]

Thanks all- it doesn't annoy me in the slightest, just nice to know what it is.

[Graham G3ZVT]

It makes you wonder why they continue to do this in in the 21 century.

Are Openreach really going to proactively investigate every fault detected on individual lines, rather than wait for the customers to report problems through their nominated service providers?

[G6Tanuki]

I too wonder why they bother, given that a lot of the users of OpenReach infrastructure will be using it for Naked Broadband and so won't have a POTS phone attached to the line.

I suppose that poking the line with a bit of 48V AC might perhaps clear some broadband issues associated with corrosion on joints on the copper..

[Station X]

There's a capacitor in the master socket so the test will prove continuity through to there.

[Buzby123]

Is it just a line continuity test, or is it more complex, such as determining the line characteristics ?.

[Oldcodger]

Originally Posted by Station X

There's a capacitor in the master socket so the test will prove continuity through to there.

That reply from the test desk folks always made me laugh when as a private engineer at a customers premises I got asked to check out something like a fax line to discover that there was no dial tone at the master socket. Testing Ok, and I can see a socket at the end of the line was the usual reply. I'd put a short on the pair and they didn't detect it. Boiled down to tele cleudo aka contractor in cab with defective eyesight( as in removed wrong jumper).
This was a regular occurance at my house, every Friday over a few months. Line dead. Test desk said everything OK, but could not detect short on master socket. Come Monday, BT man turns up and 10 minutes later returns. I ask " dis in cab", to get the same response.

[Station X]

Originally Posted by Oldcodger

Boiled down to tele cleudo aka contractor in cab with defective eyesight( as in removed wrong jumper).

That wouldn't cause the fault you describe, The line would test disconnected.

[Roger Ramjet]

I deal with the occasional alarm line fault on behalf of the company I freelance for & it tends to go like this:-

> Line Reported as faulty i.e. no dial tone

> Reply - Line Test's OK

> Yes but there is no dial tone

> Reply - Well we can attend but it will be chargeable if no fault found

> Yes ....please attend to reinstate dial tone on handset

Often - engineer attends but states no access or unable to find NTP which permits them to charge the 3rd party service provider for the visit. And so on & so on, it's even worse if the fault is a noisy line.

Roll on the Cu switch off !

Rog

[paulsherwin]

Back on topic please.

[Roger Ramjet]

The line auto test feature has been in use for many years, most likely as a designed - in feature of modern electronic exchanges.

At the time most phone line contracts would have been with BT but since then, different 3rd service provides have joined the party so in the event of a failed auto test, who would BTOR notify i.e. the service provider or the end user ?

Full transition to FTTP for telephony & broadband will no doubt make this feature redundant but who would have thought that at the time when auto test was conceived.

I am presuming that bell tinkle would happen if the line polarity was reversed during the auto test.

Rog

[McMurdo]

When I lived at home I installed a BT Renown mini pabx so my Mum could call up my dad in the sheds or put calls through to him. It did exactly the same thing, at the same time each night, a quick couple of pips on the phones...though noone had noticed it before I installed the Renown.

I was thinking about the auto test at work the other day as I saw an incoming call on our Panasonic PABX. The exchange lamp began flashing and then a good 2 or 3 seconds later the phones began ringing. I'm sure the pabx has a 'delay before ring' setting in the programming, so I wonder if this is designed to stop the line test tinkle! (or any other type of tinkle for that matter?)

[Graham G3ZVT]

The parameter that set that interval was called "Ring Bridge" on Philips SOPHO systems.

Strange the things you remember from 30 + years ago.

In a busy office, another thing that could happen is that you selected a line to make an OG call, only to find that you've answered am IC call that was just about to ring.

"Sorry, you've reached the telephone engineer, I'll put you through to reception".

Another thing that PABXs were supposed to do, is not to begin out-pulsing DP or DTMF to the trunk until 4 seconds had elapsed after seizure.
The user would be unaware of this, however I have an ordinary POTS telephone that obeys this rule for some reason, and it's quite disconcerting because If you start to dial as soon as you pick up the handset, nothing appears to happen, then you hear a string of digits go out and only then does each remaining keypress send its own tone.

I think the four second delay stems from the line finders on crossbar exchanges that were notoriously slow to deliver a dial tone. Ian Jolly will know.