Wireless systems use radio frequencies that are designated by governments for unlicensed use. For example, in North America frequencies near 49 MHz, 902 MHz or 2.4 GHz are available. While these frequencies are not assigned to powerful television or radio broadcasting transmitters, interference from other wireless devices such as cordless telephones, wireless toys, computer wireless networks, radar, Smart Power Meters and microwave ovens is possible.
Sound devices relay what is happening in baby's room via sound only. A great sound option is quiet unless the baby is making noise so that you won't be disturbed by white noise or constant static. This basic monitoring type can be all you need if your goal is being alerted when your baby is crying and needs your assistance. This style can be elementary with sound only like the V-Tech DM111 or it can have bells and whistles like a nightlight, 2-way talk, lullabies, and mic sensitivity adjustment features like the Philips Avent DECT SCD570/10. Most parents can get by with a sound only device as it provides the information you need to determine if your baby needs you or not.
The features we focused on were those we thought either increased the performance of the monitor or made it more user-friendly for parents and increased the odds of getting good quality sleep. We looked for monitors that have sound activation that keeps the parent unit quiet when the baby isn't crying, so parents can potentially fall asleep faster because they don't have to listen to white noise. Some of the monitors were so loud, even at low volumes, that the white noise might keep light sleeping parents awake; this defeats the purpose of having a video product to begin with. We also liked the models with screens that automatically "wake" and/or go to sleep.
Traditional video baby monitors don't offer the same high-resolution picture quality we're used to seeing on our smartphones and tablets. If you want high-resolution video of your baby, you'll have to go with a Wi-Fi monitor like the NestCam that streams video to your phone or tablet. The Phillips AVENT SCD630 video monitor may not be high-res, but it's the best of the bunch.
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.