The older analog 900 MHz monitors have been thought to be safer than the newer DECT baby monitors. View Google Images
A baby monitor, also known as a baby alarm, is a radio system used to remotely listen to sounds 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 the infant.
While so connected or under computer control
In or into operation or existence
on-line(a): being in progress now; "on-line editorial projects"
With processing of data carried out simultaneously with its production
on-line: on a regular route of a railroad or bus or airline system; "on-line industries"
on-line: connected to a computer network or accessible by computer; "an on-line database"