Posted by a reviewer on Amazon

I replaced the in line filter checked the connection at the phone box all the connects in the house and even had the phone service out to find the problem with a constant humming sound on the receiver with no answer but they would look into the problem

Posted by a reviewer on Amazon

I took it upon myself and bought the home tester which basically isolated the problem since i was able to check from point ab and found the phone line itself broken in the basement next to the ac line where moister was evident and causing the whole problem

Posted by a reviewer on Amazon

There is a test tone that sounds from one end to the other there is no way to get it wrong

Posted by a reviewer on Amazon

The product works as promised but the print in the instructions requires younger eyes or a magnifying glass