The FCC in the United States and IC in Canada regulate the distance in which a radio frequency from the hand-held transmitter can operate. In optimum conditions, this distance is 90 feet. Since there are many things than interfere with radio frequency the maximum realistic distance from which a hand-held transmitter will communicate with the receiver is 25 feet. Radio frequency will go through normal residential constructed walls (wood, plaster, drywall), but distance will be reduced traveling through walls.
