US718224A - Intercommunication telephone system. - Google Patents

Description

PATENTED JANEEIS, 1903; T. SLOPEB. a; I. H. PARSONS. IANTERAGOMMUNIIOATION TELEPHONE SYSTEM.

APPLIOATIOKIILLBD APB. I8, 1902 80 MODEL.

THOMAS SLOPER, OF WILTS, AND ISAAC HARDY PARSONS, OF

ENGLAND.

LEICESTER,

INTERCOMM UNICATION TELEPHONE SYSTEM.

SPECIFICATION formingpart of Letters Patent N 0. 718,224, dated January 13, 1903.

Application filed April 18' 1902.

To all whom it may concern.-

Be it known that we, THOMAS SLoPER, of'l i Brittox, Devizes, Wilts, and ISAAC HARDY PARSONS, of Faraday Works, Leicester, England, subjects of the King of Great Britain, have invented new and useful Improvements in Intercommunication Telephone Systems, of which the following is a specification.

This invention relates to improvements in intercommunication telephone systems of the kind wherein each instrument is provided with a pair of home lines having extensions or forks whereby the said lines can be con; nected to jacks or connecting devices at other instruments of the system. In such systems as heretofore constructed it is possible for a person to tap or overhear a conversation being carried on between two subscribers by simply connecting his switch to one of the speaking-lines, and it is even found in practice that overbearing can take place if only one terminal of the receiver at the tappingstation is connected to any part of a speaking-line.

Now this invention has for its object to obviate this defect, and to this end instead of connecting both the transmitter and the receiver of each instrument to the same lines or the same induction coil, as has heretofore 0 been the practice, we arrange the connections in such a manner that the receiver at each instrument is always disconnected from the transmitting apparatus of the same instrument and also from the switch or other device made use of for connection with the lines of the other stations of the system, and from the earth or common return-wire, (if any.) By transmitting apparatus we mean the microphone induction-coil or other apparatus for producing the necessary current or varia tion of potential either directly or by induction. With this arrangement it will be understood that the operator at each instrument cannot connect his receiver to any other line than his own, so that although he can hear what is spoken into his own pair of lines from any of the stations yet he can only speak to the station to the lines of which he is connected by his plug or switch.

In the accompanying drawings, Figure 1 is a diagrammatic view representing two tele- Serial No. 103,652. (No model.)

phone-stations connected up according to the invention. Fig. 2 is a similar view illustrating a slight modification.

The same characters of reference refer to the same or corresponding parts in both figures.

A and B represent the two stations.

at a are the receivers; b b, the receiverhooks; c c, the transmitters; d d, the bells; e e, the switches or plugswhich are adapted. to be connected to the jacks ff for connecting up the two stations, as hereinafter described.

g is the battery in the transmitter-circuit, and 1, 2, 3, 4., 5, and 6 represent the home lines with which receivers of the different stations are connected, the jacks f f being also connected to these lines, as clearly shown. With this arrangement when an operator at, say, station A desires to call up an operator at station E he brings his plug a in connection with the jacks f f, attached to the lines 1 and 2, and depresses the key or contact '9, whereupon the current flows through the wire 7, contact g, wire 8, plug 6, jack f, home line 2, wire 9 at station E, bell d, receiver-hook b, wire 10, home line 1, jack f at station A, plug e, and wire 11 back to the battery. The bell at station E is therefore rung, announcing to the operator in this station that some one wishes to speak to him. 7 He must therefore remove his receiver from its hook, thereby placing it in circuit with the transmitter at the calling-station A, the operator at which station can then announce to him his number. Upon receiving the number the operator at station B places his plug e into connection with the home lines corresponding to station A, whereupon his transo mitter is brought into electrical connection with the receiver at station A, thus enabling the operator at the second station to converse. It will thus be seen that the receiver at each station is in connection only with the 5 transmitter at the other stationthat is 'to say, with the station to which it isconnected by means of the plug or switch-so thatit is impossible for an operator at a third station to overhear the conversation which is proceeding, as his home line cannot be brought into electrical connection with the transmitter at either of the stations between which conversation is proceedin 72. is a buzzer or other suitable sounding device which is used for indicating to the operator at the calling-station that his call is answered, and in the arrangement shown in Fig. 1 this buzzer is inserted in the signalingcircuit, beingadvantageously operated by the signaling-current, although an independent signaling-current at the called station may be used, if found more convenient.

In order that the signaling-current at a third station shall not be sent through a receiver at either one of the two stations in conversation, we may connect one terminal of the bell at each station to a common return-line 11 or earth, as is indicated in the arrangement shown in Fig.2. In this arrangement we have shown a magneto-machine 7' for generating the necessary current for signaling purposes, although we wish it to be understood that an ordinary ringing-battery could be employed, if desired, and also that such a magneto-generator could be used for ringing in the arrangement shown in Fig. 1 in lieu of the battery there illustrated.

When the connections are made as shown in Fig. 2 and the subscriber at station A desires to ring up the subscriber at station B, the subscriber at the former station operates his magneto-generatorj so as to cause a current to flow from the said generator through the line 11, switch-plug 9, jack f, home line 1, line 10 at station E, receiver-hook Z), bell d, and common return-line or earth 2' back to the generator A key may be provided at 7a, which may be operated by hand while ringing, or it may be so arranged that it is automatically operated when the generator is used.

Assume now that the receiver at station B is removed from its hook and that a subscriber at another station endeavors to ring up station E. In this case the circuit between the home line 1 and the return-wire t' is broken at the receiver-hook b, so that no current flows, and thus the subscriber using the receiver-at station E is not subjected to the annoyance of being rung up while he is using the receiver. At the same time the subscriber at the calling-station is made aware that the subscriber at station E is engaged, as he receives no announcement on his sounder that his signal has been received.

Having now particularly described and ascertained the nature of oursaid invention and in what manner the same is to be performed, we declare that what we claim is 1. In an intcrcommunication telephone system, the combination of a plurality of stations each having a receiver, a circuit for the receiver extending to the other stations, and a transmitter at all times entirely discon nected from the said receiver-circuit, and adapted to be connected to the receiver-circuit of another station, substantially as described.

2. In an intercommunication telephone system, the combination of a plurality of stations each provided with a transmitter and a receiver at all times in a different circuit from the transmitter, and means for connecting the transmitter of one station with the receiver only of other stations, substantially as described.

3. In an intercom munication telephone system, the combination of a plurality of stations each provided with a transmitter and a receiver in a diiferent circuit from the transmitter, a plurality of lines connecting said stations, and a circuit-controlling device for each station, in the transmitter-circuit thereof for connecting said transmitter with the receiver of a called station, substantially as described.

4. In an intercommunication telephone system, the combination of a plurality of stations, each station having its receiver and transmitter in separate and independent circuits and a circuit-controller in a circuit independent of the receiver circuit for connecting the transmitter of one station to the receiver of other stations, substantially as described.

5. In an intercommunication telephone system, the combination of a plurality of stations, each having a receiver and a transmitter and a pair of home-line wires connected to its receiver only, and extending to each of the other stations and means at each station for placing the transmitter only thereof in connection with the home lines leading to the receiver only of another station, substantially as described.

6. In an intercommunication telephone system, the combination of a plurality of stations each having a receiver, a pair of home lines for the receiver leading to each of the other stations, a call device in a shunt-circuit connected with said home lines, a transmitter, at all times disconnected from said home lines leading to the receiver, a circuit-controller for connecting said transmitter with the home lines, of another station, and a switch for cutting the said call device out of the receivercircuit and placing the receiver in said circuit, substantially as described.

7. In anintercommunication telephone system, the combination of a plurality of stations each having a receiver, a pair of home lines therefor, leading to all the other stations, a call device in a shunt of the receivercircuit, a switch for cutting out said call device and placing said receiver in connection with said home lines, a transmitter at all times disconnected from said home lines, a separate circuit for said transmitter, a controller in said circuit for placing the transmitter in connection with the home lines leading to the receiver of another circuit and an electric signal in said transmitter circuit, substantially as described.

8. In an intercommunication telephone system, the combination of a plurality of stations each having a receiver, a pair of home lines therefor, leading to all the other stations, a call device in a shunt of the receivercircuit, a switch for cutting out said call device and placing said receiver in connection with said home lines, a transmitter at all times disconnected from said home lines, a separate circuit for said transmitter, a controller in said circuit for placing the transmitterin connection with the home lines leading to the receiver of another circuit, an electric signal in a shunt-circuit in said transmitter-circuit and a switch for cutting said signal into and out of said circuit, substantially as described.

9. In an intercommunication telephone system, the combination of a plurality of stations each provided with a receiver, a circuit therefor including a pair of home lines leading to all the other stations, a call device in a shunt-circuit of said receiver-circuit, a

THOMAS SLOPER. ISAAC HARDY PARSONS.

Witnesses:

O. G. REDFERN, A. ALBUTT.

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