A typical baby monitor is a simplex transmitter and receiver system, used to remotely listen for noises made by an infant. The transmitter, equipped with a microphone, is placed near to the child and the receiver equipped with a speaker, is carried by, or near to, the person caring for them at the time. Some baby monitors are duplex, using transceivers that allow the caregiver to communicate back to the baby and some have a feature allowing music to be played on the transmitter and thus played to the child.
One of the primary uses of baby monitor is when the infant is asleep in a separate room or floor, allowing caregivers or parents to keep track of any problems while away from the baby. With the kind of world we are leaving now it is better not to take chances. The safety of your child comes first and hence you should make an effort of checking on him/her every now and then.
For those worried about sudden infant death, a monitor should only be used under the supervision of a pediatrician or other doctor. Although commonly used, there is no evidence that these monitors prevent SIDS, and many doctors believe they provide a false sense of security.
Some modern baby monitors also incorporate a video camera to show pictures on the receiver using radio waves in the unlicensed 2.4 GHz band, either by plugging the receiver into a television or by including a portable LCD screen; they are often called baby cams some baby cams can work with low minimum light level (night mode). Most video baby monitor today has night vision feature. These devices can be bought from baby stores or even over the internet and they are at affordable prices.