Wireless doorbells use a radio transmitter to send a signal to a receiver, which activates the sound or chime alerting the occupant that someone is at the door. Unlike traditional doorbells that make the alert using electromagnets to activate plungers against tone bars, most wireless doorbells use a prerecording of chimes.
The primary advantage of wireless doorbells is they do not require installing wires between the button at the door, the transformer and the chimes. Transmitters often use batteries, while the sound device either plugs into household current or uses batteries.
One common complaint about wireless doorbells is that the chimes sometimes sound when no one activates the transmitter button. Often this is due to a nearby neighbor with a similar device installed in his home. Most wireless sets allow the owner to change the frequency of the transmitter and receiver, which usually eliminates this problem entirely.
If the doorbell does not activate upon pressing the transmitter button, the problem is often weak or dead batteries. Replacing the old batteries with new ones usually fixes the unit immediately. There is also a limit for the distance between the transmitter and sounding unit. Concrete interferes with some units, but mounting them on small pieces of wood easily solves this problem.