Troubleshoot a noisy home phone line

Ensure no changes have been made in the home or any devices installed when the problem first occurred. Remove any new devices if the timing coincides and retest.

If there are multiple handsets within your home, check to see if the issue is occurring with the other handsets as well

Unplug all equipment from every phone jack including fax machines, modems, splitters, etc.

Leave everything unplugged for a minimum of 60 seconds, then plug in your most basic telephone. Use a corded phone if you have one.

Check for any noise, static or radio interference.

Add equipment (phones, fax machines, modems, splitters) back one piece at a time, continually checking for the return of any noise or static. If the issue returns, remove the last piece of equipment added from the jack. It's probably causing the problem and you may want to have it checked.