Nikola Tesla U.S. Patent 725,605 - System of Signaling Patent Wrapper Page 45

J Sub. Spec. 荧 4373 2. In a system for the transmission of electrical inpulses and the operation or control of signalling or other apparatus thereby, the combination with a transmitter adapted to produce two or more distinctive kinds or classes of \ disturbances or impulses, of sensitive receiving circuits, each tuned to respond to the impulses or disturbances of one kind or class only, and a receiving device dependert for operation upon the conjoint action of the sensitive circuits, as set forth. 3. In a system for the transmission of electrical impulses, and the operation or control of signalling, or other apparatus thereby, the combination with a transmitter adapted to produce two or more distinctive kinds or classes. of disturbances or impulses, of sensitive circuits at the receiving point or station, each tuned to respond to the V 1 impulses or disturbances of one kind or class only, a local circuit arranged to be completed by the conjoint action of the sensitive circuits and a receiving device connected therewith, as set forth. 4. In a system for the transmission of electrical inpulses and the operation or control of signalling or other apparatus thereby, the combination with a transmitting apparatus adapted to produce two or more distinctive kinds of disturbances or impulses, ofr nears for varying the time intervals of the emission of the inpulses of the several kinds, sensitive circuits each tuned to respond to the impulses or disturbances of one kind only, and a receiving apparatus dependent for operation upon the conjoint action of the sensitive. circuits, as set forth. 5. In a system, such as herein described, the combina-11[Portion of margin notes not legible - Ed. 659