21 APPARATUS AND EQUIPMENT FOR USE IN PAGING SERVICE, SUCH APPARATUS AND EQUIPMENT CONSISTING OF ELECTRICALLY-OPERATED CODE SENDERS AND SIGNAL TRANSMITTERS FOR USE IN AUTOMATIC CODE SIGNALING; ELECTRICALLY OPERATED OR CONTROLLED BELLS, GONGS, AND BUZERS; AND ELECTRIC MOTORS, SWITCHES, PANAL BOARDS, BATTERIES, AND COMPONENTS OF APPARATUS AS AFORESAID