Believe it or not, that is good

! It is easier to cure the problem if you have this happening.
Was it a corded or cordless phone?
The ideal test is a corded phone into the test socket, on the wall at the back in
this pic. All other phones should stop working when you have the master open.
You don't have a burglar alarm wired into the phone do you?
Assuming you don't have such a burglar alarm, if there is noise on this test then you simply report a
phone line fault to whoever you pay line rental to. Tell them you are getting noise on the line.
Do not mention broadband, not even as a point of interest, because if you do they will tell you to go back to your ISP.
As there is a line fault affecting voice, there is a requirement for that fault to be fixed. Get it fixed, and in 99% of cases the broadband is automatically fixed.
For an ISP to get it sorted is always very difficult for many reasons.
My broadband basic info/help site - www.robertos.me.uk
My domains,website and mail hosting - Tsohost.
Internet connection - O2 Standard.