To check for line noise, (Do this on each line) pick up the phone and dial 1. You should hear nothing. If you hear a noise, go to the phone box outside of your house. Connect a phone to that box and do the same test to check for noise. If there is noise, it is a problem with the phone company. If there is no noise, turn all appliances off inside. Then do the test to check for line noise. If there is no noise, turn one appliance on, check for noise, then turn on another if there is no noise. When there is noise after turning on a certain appliance, try to put that appliance away from phone lines.
If you find there is noise on the phone line you need to call your phone line supplier or if the supplier is us – drop us an email or use the contact page and we will get Openreach to look into the issue.