A baby monitor, also known as a baby alarm, is a radio system used to remotely listen to sounds made by an infant. An audio monitor consists of a transmitter unit, equipped with a microphone, placed near to the child. It transmits the sounds by radio waves to a receiver unit with a speaker carried by, or near to, the person caring for the infant. Some baby monitors provide two-way communication which allows the parent to speak back to the baby (parent talk-back). Some allow music to be played to the child. A monitor with a video camera and receiver is often called a baby cam.
Gone are the days of silently peeking into the nursery to check on your napping baby and then, whoops, accidentally waking them up (“No, no, please no!”). A baby monitor uses a camera to watch over the crib, while you carry a handheld device that lets you know what’s going on with your child at any given moment, no matter where you are in your home. There are also other monitors that track sleep or breathing either with a clip or sock.