US2761014A - Multiple-station selective communication system with single amplifier - Google Patents

Description

MULTIPLE-STATION SELECTIVE COMMUNICATION SYSTEM WITH SINGLE AMPLIFIER Filed March 19, 1953 Aug- 28, 1956 E J. NovREsKE 2,761,014

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FOU/Q MULTIPLE-STATION SELECTIVE COMMUNICA- TION SYSTEM WITH SINGLE AMPLIFIER Emanual J. Novreske, Gary, Ind., assigner to United States Steel Corporation, a corporation of New Jersey Application March 19, 1953, Serial No. 343,428

2 Claims. (Cl. 179-40) This invention relates to an improved multiple station selective communication system.

An object of the invention is to provide a system of the foregoing type which includes as many stations as desired and in which any station can communicate both ways with any other station with only a single amplifier for the entire system.

A further object is to simplify communicating systems of the foregoing type by employing only a single amplifier for the entire system while allowing two-way communication between any two stations thereof.

In accomplishing these and other objects of the invention, I have provided improved details of structure, a preferred form of which is shown in the accompanying drawing, in which:

The single figure is a schematic wiring diagram of a communication system embodying the present invention.

The communication system of my invention comprises any desired number of stations, illustrated as four in number, and designated in the drawing by the legends Station One, Station Two, etc. Each station includes a combination speaker and microphone 10, a press-to-talk key 12, and three station selector switches 13 which are designated by appropriate legends. These selector switches normally are open. When a user at any station talks to another station, he closes the selector switch at the former station indicated by the legend thereon as connected to the latter station. The system also comprises a single amplifier and power supply unit 14. Inasmuch as the combination speakers and microphones and the amplifier and power supply unit per se can be of any standard or desirable construction and are not part of the present invention, no detailed showing is included.

Each press-to-talk key 12 has three front or normally open contacts 15, 16 and 17 and two back or normally closed contacts 18 and 19. This key normally is in a position for its station to receive communications from the other stations and thus for the combination speaker and microphone 10 to function as a speaker. Conductors 20 and 21 connect the combination speaker and microphone lil with the back contacts 18 and 19 respectively as long as the key is in its normal receiving position. The back contact 18 of the key in Station One is connected to one of four conductors 22. This conductor 22 has branches which extend to the station selector switch for Station One in each of the other stations. The back contacts 18 of the keys in the other stations are correspondingly connected to similarly arranged conductors 22 so that, whenever a station selector switch in any of the stations is closed, a connection is established from that switch to the back contact 18 of the selected station. The back contacts 19 of the keys of all the stations are connected via a conductor 23 to one side of the output from the amplifier and power supply 14. The front contacts 17 of each key are connected via a conductor 24 to each of the three selector switches 13 of that station and via a conductor 25 to the other side of the States Patent VO ICC output from the amplier and power supply 14. Conductors 26 and 27 connect the front contacts 15 and 16 respectively of each key 12 to the input to said amplifier and power transformer.

In operation, assume as an example that a user at Station One wishes to communicate with another user at Station Four. The user at Station One closes both the Station Four selector switch 13 and the press-totalk key 12, as indicated in dotted lines in the drawing. At Station One the combination speaker and microphone 10 now acts as a microphone, and at Station Four as a speaker. At Station One conductors 20 and 21 are connected through the key 12 to the front contacts 15 and 16 thereof (now closed), and said contacts are connected via the conductors 26 and 27 to the input of the amplifier and power supply 14. Thus the spoken signal is transmitted to the amplifier. The conductor 23 connects one side of the amplier output to the back contact 19 of the key 12 at Station Four. As long as said key is in its receiving position, the conductor 21 at this station connects this back contact with one side of its speaker 10. At Station One the conductor 25 connects the other side of the amplifier output to the conductor 24 via the front contacts 17 (now closed). Also at Station One the selector switch for Station Four (now closed) connects the conductor 24 to the conductor 22 which leads to the back contact 18 of Station Four. At the latter station the conductor 20 connects this contact with the other side of the speaker 10. Thus there is established a complete circuit from the microphone of StationOne through the amplifier and power supply 14 to the speaker of Station Four. In like manner circuits can be set up from the microphone of any of the stations through the amplifier and power supply to the speaker of any other station by closing the appropriate key 12 and station selector switch 13.

It is seen that the system of my invention enables a single amplifier and power supply to serve for the whole system. In usual installations when two-way communication is possible between all stations, separate amplifiers are required for each station.

While I have shown and described only a single embodiment of the invention, it is apparent that modifications may arise. Therefore, I do not wish to be limited to the disclosure set forth but only by the scope of the appended claims.

I claim:

1. A communication system comprising a single amplifier and power supply, a plurality of stations, each of which includes a combination speaker and microphone, a press-to-talk key having two back and three front contacts, connections between said back contacts and said speaker and microphone, and normally open station selector switches for the other stations arranged for connection to one of said front contacts when the key is pressed, connections between each of said selector switches and one of the back contacts of the station to which it corresponds, a connection between the output of said amplifier and power supply and the other back contact of each station, a connection between the output of said amplifier and power supply and that front contact at each station arranged for connection to said station selector switches, and connections between the two other front contacts at each station and the input to said amplifier and power supply, said last named connections being independent of the connections from the output of said amplifier and power supply, said connections enabling any of said stations to communicate both ways with 'any other with only one amplifier.

2. A communication system comprising a single amplifier and power supply having a pair of input terminals and a pair of output terminals, a plurality of stations each having a combination speaker and microphone, a press-to-talk keynormally in a receiving position, and normally open station selector switches for the other stations, each of said combination speakers and microphones having connections with one of said output terminals and with the selector switches therefor at the other stations via its own key when lthe latter is in its receiving position, conductors between the other output terminal and said keys and between each of said keys and the selector switches at that station, said conductors completing a circuit from said other output terminal to one of said combination speakers and microphones when the key at any other station is in its transmitting position and the corresponding selector switch at that other station is closed, and conductors between each of said keys and both of said input terminals, said last named References Cited in the le of this patent UNITED STATES PATENTS 2,275,405 Berhley Mar. 10, 1942 2,493,174 Vincent Ian. 3, 1950 2,523,671 Vincent Sept. 26, 1950 2,554,912 Kilminster May 29, 1951 2,561,946 Pedatella July 24, 1951

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