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Message 1 of 7

Intermittent Dial tone fault on Landline

Hi

Periodically I get a fault where there's no dial tone on my landline phone. It will stay like that as long as I leave it alone. If I run the online troubleshooter it tells me there's an external fault and an engineer will fix it, but the dial tone comes back once the diagnostic have been run so the engineer reports no fault found. I've also found out that if I call my landline from my mobile it rings and the dial tone is restored afterwards. This has been happening on and off for over a year. Has anyone else experienced this?

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Distinguished Sage
Distinguished Sage
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Message 2 of 7

Re: Intermittent Dial tone fault on Landline

sounds like a high resistance fault and needs engineer visit but not to home  need to phone 151 and report phone fault not broadband



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Message 3 of 7

Re: Intermittent Dial tone fault on Landline

@PayingForAService. Thanks for posting. Yes, I've seen this happen before, an engineer explained that the additional current that is put on your line when you test it or call from your mobile to make it ring blows off oxidation that may have formed on a faulty join on the line. 

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Distinguished Sage
Distinguished Sage
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Message 4 of 7

Re: Intermittent Dial tone fault on Landline

Agreed, a very common problem. It can be caused by a bad joint, or a faulty line card.

During a line test, relays in the line card connect to the line test matrix. The line tester does a number of very basic line tests, but that is often enough to clear any problems.

Ringing your line from a mobile sends out 80V AC out to your phone, which again is very effective in clearing faults.

Even picking up the phone fro time to time can help.

The problem with high resistance faults was very common on Analogue Private Circuits, and can also show up on people who have broadband, and never use their phone line.

I do have a more comprehensive explanation on my community help website regarding phones and broadband. Why do I need a landline phone?

 

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Distinguished Sage
Distinguished Sage
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Message 5 of 7

Re: Intermittent Dial tone fault on Landline

@PayingForAService 

What I would say, is that if the problem persists, then BT needs to change you to a different EN (Equipment Number) in the exchange to eliminate the possibility of a faulty line card port.

That is an easy task for an Exchange Frames Technician.

Perhaps that would be the best way forward?

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Message 6 of 7

Re: Intermittent Dial tone fault on Landline

I just spoke to the Engineer at the exchange & relayed your comments, along with ones from other contributors. He said that he couldn't trace a high resistance joint while there was no fault present, and he didn't think it was worth changing to a different EN as the type of equipment at the exchange (concentrator?) was extremely reliable & if it was faulty there would be other users with problems. Looks like I'm stuck with the problem until it gets bad enough not to clear itself when I run diagnostics.

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Distinguished Sage
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Message 7 of 7

Re: Intermittent Dial tone fault on Landline

Exchange line cards are  unreliable as they are very old and develop faulty relays which often cause either no dial tone, or no ringing current.

It would not affect other users, as your port on the line card is unique to your connection.

Changing the EN simply involves rewiring your phone line to a spare port on another line card, then making a call (it may be an automatically submitted request now), and asking that your phone number be re-mapped to the new port allocation. That does not take very long.

That would then eliminate one possible cause of no dial tone.

 

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