Nikola Tesla U.S. Patent 725,605 - System of Signaling Patent Wrapper Page 46

660 Aut. Spect per B. F Came per Sub. Ple F Spu. B/ tion with a transmitter adapted to produce a plurality of distinctive kinds of electrical disturbances or impulses, of a receiving apparatus comprising a plurality of circuits, a sensitive device and a relay included in each circuit, evde Raid circit being and tuned to respond to the impulses or disturbances of one kind only, and a receiving apparatus in a local circuit controlled by the relays and adapted to be completed by the conjoint action of all of said relays, as set forth. 6. In a system of the kind described, the combination with a transmitter adapted to produce two or more series of electrical oscillations or impulses of different frequencies, of a receiving apparatus comprising a plurality of sensitive circuits each tuned to respond to the impulses of one of the series produced by the transmitter, and a signalling device dependent for its operation upon the conjoint action of said circuits as set forth. impulses 7. The combination with a plurality of transmitter elements, each adapted to produce a series. disturbances of a distinctive character, and means for controlling and adjusting the same ame , of a receiver having a 1 plurality of sensitive circuits each tuned ao as to be affected by one of the series of impulses only, and dependent for operation upon the conjoint action of all of said circuits, as set forth. 8. The combination with a transmitter adapted to produce series of electrical impulses or disturbances of distinctive character and in a given order of succession, tuned of a receiving apparatus comprising circuits tuned to A respond to such impulses in a corresponding order, end dependert for operation upon the conjoint action of said elements, as set forth. or -12