Nikola Tesla U.S. Patent 725,605 - System of Signaling Patent Wrapper Page 13

J J J J -7circuits at the distant station, each responding to one of the transmitted vibrations, /affect the sensitive devices al and a² and cause the relays R1 and R² to be operated and contacts c1 and 2 closed, thus actuating the receiver or relay R3, which in turn establishes a contact 3 and brings into action a device a3 by means of a battery b included in a local circuit, as shown. But evidently, if through any extraneous disturbance only one of the circuits at the receiving station is affected, the relay R3 will fail to respond. In this way communication may be carried on with much increased safety, and entire privacy of the message may be secured. The receiving station shown in Fig.2 is supposed to be one requiring no return message, but if the use of the system is such that this is necessary, then the two stations will be equipped similarly, and well-known means, which it is not thought necessary to illustrate here will be resorted to for enabling the apparatus at each station to be used in turn as transmitter and receiver. In similar manner the operation of a receiver, as R3 may be made dependent, instead of upon two, upon more than two such transmitting systems or circuits, and in this 1 manner any desired degree of safety may be attained. The 1 apparatus, as illustrated in Fig.1, permits, however, specific results to be attained by the adjustment of the phase e/pha: difference between the mary circuits Pl and P2.. discharges of the priTo illustrate, the rela y R1, R2 may be regulated, either by adjusting batteries the weights of the le vers 11 12, or the strength of the A 627