You probably have a wireless phone, so why not a wireless doorbell? The advantages of a wireless door chime include simple installation, no wires to run, and portability to any room (or even taken out to the garage).
How do wireless doorbells work? When a visitor pushes your doorbell button, a radio signal is transmitted and picked up by a receiver which then triggers the chime, buzzer, or light feature of your doorbell. The majority of wireless chimes have variable frequencies to reduce interference with any neighboring doorbells.
Some wireless doorbells plug directly into an electrical outlet while others are powered by batteries. There are even handy portable models which can be carried like a pager. Most wireless chimes can also be mounted on the wall like a traditional wired doorbell.
Many doorbell manufacturers feature compatibility between their wireless models, so that you can have multiple units around your property. Another feature often offered is the ability to add pushbuttons at other entry doors you may have. The ring tones of these buttons can be synchronized or customized with different sounds, so that you can identify at which door your visitor is waiting.