To install wired door chimes, connect a wire from the doorbell's button to a terminal on the transformer and then from the transformer to the chime. Run a second wire from the button to the chime mechanism. Connect the transformer to a power source to complete the installation. Each button in the system connects to its own transformer terminal.
Most doorbell and door chime systems are sold with the transformer. If you're using an existing transformer but changing other parts of the system, consult the manufacturer's information and an electrician if necessary to ensure the transformer is the right kind.
If you're updating an existing system and need to find the transformer, check high up in any closets close to the chime mechanism. Chimes are often installed in the central part of the home between the front rooms and bedrooms.
If the transformer isn't in a closet, check in the garage and close to the water heater. Use a multitester to ensure there are 18 to 24 volts of alternating current running through the transformer, and disconnect at least one wire before continuing with the installation.
Finish the installation by connecting the circuit's wires to the transformer and turning on the power. Test each button in the system.