When BT Infinity was installed a new overhead cable was put in. (Black round 4 wires). This comes to a junction connected directly to the old phone wire which runs through the loft and house to two BT phone points. (Grey flat 2 wire like 45 ohm feeder). At the junction the black cable continues to the broadband box which has a phone socket (unused). I presume the old phone wiring should have been connected to the broadband phone socket or a filter fitted to stop radiation from the old phone connection which I think is my problem.