Yesterday we had a ticket on our schedule to help customer install a ring doorbell. When we arrived, we realized that the customer had a wireless doorbell. Right next to it, was a face plate that cover where the old doorbell was. My guess is that doorbell stopped working. This can be two reasons, bad wiring or bad power supply. After we trace the cable down, we realize the the customer use to have a phone system install in this home. They had a intercom system tie to the phone system, therefore, the doorbell wiring did not had power to it. This create a small dilemma for us, we ended up ordering a power supply and have to make a second trip just to install a Ring door bell. After installing probably 30 ring door bell, we still are still on a learning curve. Welcome to the IT business!