I don't know what the exact issue is, but I will throw in two cents worth. DSL uses "excess" bandwidth on the twisted pair copper phone wires leaving your house. In this case, the "excess" bandwidth is starting somewhere above 10KHz and going up to several Megahertz, typically well above the AM broadcast band. The DSL signal starts just above the usual telephone audio band and would be audible noise in your telephone if you didn't use the filters they ship with the DSL modem. I've had small transformers and inductors generate noise before, particularly when it was tones above the usual voice range, and a kind of "spiky" waveform. This is fairly common where the wire winding on the transformer is a bit loose or where it wasn't painted with shellac or something that would prevent vibration. As a quick fix, I've used a layer of Crazy Glue to glue the wires in place so they couldn't vibrate any more. If there is a DSL filter built into the jack or there is a DSL filter module attached at the wall jack, I wouldn't be too surprised if the wire in one of the inductors in the filter was vibrating in time to one of the DSL signal components and you could hear it in a quiet room. It should tend to be just the high pitch sounds and would not approach full fidelity, but I wouldn't find it hard to believe. If you want hard to believe, I live less than 1 mile from the KSTP AM towers in Maplewood. One time about 30 years ago, on a very quiet summer night, I'd swear I was hearing KSTP audio from the rusty rain gutters outside the kitchen windows. I suppose it could have been coming from the hot water radiator under the windows.... I never did figure out what that could have been vibrating to convert RF to air movement.... Doug.