If the parents sleep in a different room from the baby, it would prove to be impossible to be able to monitor him or her perfectly unless you wake up every minute and check up on your little tyke. So the best way to do this is to use a baby monitor. With this kind of device, you can monitor your baby as if you were actually right there beside him or her. First and foremost, baby monitors work more efficiently between ground floor and first floor areas. However, if your home is made of thick concrete walls or has aluminum siding, then this can terribly decrease the strength of the transmitted signal. Parents who own baby monitors have also reported instances of interference. As a rule, you need to place the radio transmitter within 10 feet of the crib so that it can pick up even the slightest sounds made by your baby such as breathing and movement. You can then carry the portable receiver around during the day or just leave it plugged in at the side of your bed at nighttime. Another advantage that digital technology has is that it provides clearer reception. The digital receivers, whether a microphone or s camera, are also more sensitive to sound and visuals respectively. One problem of analog baby monitor devices is the fact that there are instances when neighbours can actually tap in to the signal of your baby monitors and listen. From the simple transmitter and receiver device, different baby monitors have been developed. Currently, there are two types of baby monitors: video baby monitors and audio baby monitors. Video baby monitors, as the name implies, use video footages for overseeing events in the room where the baby is located. Even though it is normal, it may also be a symptom of something more serious that is health related. Basically there are three types of apnea: obstructive, central and mixed. Obstructive apnea is most common in babies and children. It is caused by obstructions in the airway such as adenoids and enlarged tonsils.