Dial tone noise on landline

sonysean

Apologies if this isn't the correct forum for this question.

For a long time now, our landline phone (we don't use it much these days) has a strange continuous sounding 'dial tone' sound that plays whenever a blank answerphone message is left.

So all you'll hear in the "message" (they've obviously ended the call before leaving anything) is a dial tone sound that lasts for a few seconds, and then it ends.

It's just something I've never figured out myself, but I've never really looked in to it to see if I can find what causes this to happen, until now at least.

Our landline phone is a Panasonic KX-TG8522EB and we have a BT line.

techquest

Sounds like it's a tone that is generated when the distant end clears down, having not left a message, and your answerphone is left there listening to it while the equipment in your exchange is clearing down the call.

Greg Hook

That tone is when you have a message. Go into 1571 and see what it says.

techquest

Why would that be, assuming @sonysean is referring to using the answerphone capabilities of the   Panasonic KX-TG8522EB.

sonysean

Yes I am meaning the answerphone on the device itself, and don't believe I have any messages on the 1571 service.

I couldn't find anything like my 'issue' elsewhere, so I assume this is not the norm? Do you know of any way to sort it myself?

techquest

No it's nothing to do with 1571, that is only relevant to a BT answering service. You are clearly saying it's coming from the KX-TG8522EB's answering machine.

I still believe it's down to the caller having left no message and hanging up, your exchange detecting this and putting a tone on the line, the KX-TG8522EB then picking up this tone and you then hearing it.

Your local telephone exchange, are you out in a rural area?

LV426

I'd agree; I get these, and the originating numbers (I have callerID) are invariably numbers I don't recognise.  But the same thing happens occasionally with known numbers as well.  

My guess is this sequence of events
- incoming call
- answerphone answers it and begins recording
- caller hangs up
- answerphone continues to record the only thing that's on the line, which is the dial tone.

techquest

Yes I would agree with that save that it's not dial tone but a no tone or like an NU tone to let you know the caller has cleared the line.

sonysean

I'm not really in a rural area no.

By the sounds of it I'm guessing there isn't really anything I could do to stop the annoyance from happening.

Thanks for explaining

techquest

No you can't do anything about it as it is a condition your exchange puts on the line stating the caller has cleared. You have confirmed it only happens when the message is blank and therefor I believe that is exactly what is happening. I base this on my experience as an ex BT engineer having worked in telephone exchanges for a number of years.