an improved paging procedure for use in a low power radio communications network . a transceiver which pages a device by periodically transmitting a series of messages , comprises a transmitter which transmits a series of messages comprising a message at each frequency in a predetermined series of frequencies , a receiver which receives at , at least a predetermined frequency ; and a controller which enables the transmitter and then the receiver in each of a plurality of successive periods and provides each message in said series of messages . the predetermined series of frequencies is an ordered series . a first message in the series of messages transmitted in a period defines directly or indirectly when the receiver is enabled and a second message in the series , a mark code , directly defines the predetermined frequency .