But when examined by professional ghost hunters, they turn out to be ghost voices also known as electronic voice phenomenon. Baby Monitors and Interference Baby monitors can either be wired and wireless. Both types of devices have their own advantages and disadvantages. For wireless devices though, one of the disadvantages is interference. The audio baby monitor receives and sends sound so that the parent could hear the baby from a distance. The video monitor on the other hand works like a tiny TV by having a camera record the baby s movements while the parent could watch on a small screen receiver. And the sensory monitor is a movement detector that alarms the parent when it cannot perceive any movement from the child for more than 20 seconds. But as of today, parents usually prefer the wireless devices over wired ones for reasons of mobility. With wireless devices, parents can go anywhere around the house while still being able to keep tabs over their babies. The only setbacks of wireless baby monitors are that it can be more expensive to wired devices and they are also prone to interference. After that you can switch on all other devices but you should always have the cordless phone switched on last. Another way to fix interference issues is by using digital baby monitors instead of analog ones. The latest digital technology has incorporated some fixes to solve interferences. The only setback with this solution is that it may cost you a little bit more. However, the much-improved two-way monitors can allow parents to talk back to their child with their own portable transmitter. Parents who have children with separation anxiety often prefer this type of monitor, as hearing a familiar voice could usually calm the child. What are the major benefits of getting a two-way monitor? In choosing a baby sleep apnea monitor, there are certain features that the device must have to ensure the proper monitoring of your baby. Heart Beat Monitor This feature is a must for the device that you will choose since no apnea monitor is 100 percent accurate in detecting cessation of breathing. This will serve as a backup in case the apnea monitor fails to detect apnea because it will also manifest in the heart rate of the baby.