I have more than one telephone in the house in different rooms. The one on my desk in the study is a replica old fashioned one with a bell rather than an electronic ring tone but otherwise a normal modern instrument inside the casing. I switched to Virgin a couple of months ago since when the study phone emits at irregular intervals a single "ting" of the bell. None of the other phones are affected. I cannot switch the bell off and it does become slightly irritating if I am at the desk for any length of time. Does the Virgin phone line send pulses along the line that would cause this? I am slightly bemused otherwise. The phone works normally.
The sound is irregular. I have tried timing the pause between them but the lapse between them varies, usually around 20-30 minutes, sometimes longer. It is as if the 'phone is about to ring but doesn't, just a single soft "ting". This only started after we had the Virgin 'phone line installed and I have had that particular 'phone from new for about 4 years. I suppose in the grand scheme of things it is no real drama, but slightly irritating when I am sitting in the study for any length of time. The other 'phones in the house, which don't have a bell inside them but modern ring tones don't suffer from whatever is causing this. The study 'phone is not connected to an electrical socket, just a telephone socket and is not paired with anything else. It works normally for both incoming and outgoing calls. I am intrigued rather than annoyed.