These devices are made up of a transmission unit and a receiver. The first is placed in the baby�s room, and plugged in so that it picks up any noise they make (crying, coughing...) and sends it to the receiver (located where the parents are and which operates via the mains supply or batteries), which plays it back immediately. The worried parents are thus aware of everything that is happening.

 

There are many types of baby monitors. The most sophisticated have built-in movement detectors and even have a video surveillance camera, whilst simpler models, which are those more commonly used, only pick up sounds and transmit them. Prices range from 50 euros for the latter to over 100 euros for the more modern ones.

 

When buying a baby monitor you must bear in mind the characteristics of the house and the different functions the device offers. If it is a big property and the child�s room is far away from that of its parents or from the lounge, for example, it is sensible to have a monitor which provides good long distance sound quality. With this in mind, you must remember that the distance between the transmitter and the receiver which appears in the instruction manual refers to ideal conditions, in other words, open spaces where there are no obstacles.

 

Generally, at a distance of less than 50 metres in a real environment including internal partitions, there are not usually any reception problems. Beyond 50 metres, the transmission quality drops, so you should not pay too much attention to what the instructions say.

 

Baby monitors also have several channels (usually two, although there are models which have up to 30) so that if there is interference on any of them you can change to another where the reception is clearer. Some receivers also have a visual sound indicator (the louder the noise the more lights light up) and allow you to adjust the noise threshold from which the device starts to transmit. Furthermore, transmitters can come with sound level control, such that whilst a defined level is not exceeded, the receiver does not produce any sound.

 

Other characteristics are the low-battery warning (which may be a tone, as with mobile phones) and the warning which tells you when the receiver is losing reception. There are also models which work simultaneously as both the transmitter and the receiver. Where babies are concerned, such devices are of no use but they are practical when looking after the elderly and the sick. Other models are equipped with earphones so that you can monitor your baby without disturbing other people.

 

For parents who want more than just being able to hear their baby, there are monitors which have a built-in video surveillance system with night vision. They are the most expensive models but are perhaps those which provide parents with the most reassurance, particularly when the baby reaches the stage where they can get out of the cot, with the associated risk that they might fall.

 

These devices are composed of a camera (which is placed in the child�s bedroom) with a built-in microphone, and a monitor which captures the images. The camera, in the most advanced models, transmits sound and colour video (in black and white in night vision mode) to the monitor, which can even be connected to a video recorder in order to record the picture. The transmission distance can reach 100 metres (where there are no beams in the way).