Abstract :
IN normal times electrical protection through the use of protective signaling systems has been used widely to protect industrial and mercantile premises and banks, but with the advent of the war, a host of protection engineers have been making serious studies relative to plant protection. As used herein, the term protective signaling is confined to the control of property and life hazards involved in fire, intrusion, and related risks. The functional technique of such protective devices does not differ greatly from that employed in the code signaling and communication field, but because they are emergency systems, infrequently used, their reliability must be exceptionally high. Protective signaling systems,1 however, are definitely not in the communication field, as the only use of communication facilities in these services is for signaling between the protected premises and the central receiving headquarters.
