US303714A - Telephone-exchange system and apparatus - Google Patents

Description

(No Model.)

H. H. ELDRED.

TELEPHONE EXCHANGE SYSTEM AND APPARATUS.

No. 303,714. Patented Aug. 19, 1884.

g ilnrrnn STATES PATENT @FFICE,

HORACE H. ELDRED, OF NEXV YORK, N. Y., ASSIGNOR, BY MESNE ASSIGN MENTS, TO THE \VESTERN ELECTRIC COMPANY, CF CHICAGO, ILLINOIS.

TELEPHONE-EXCHANGE SYSTEM AND APPARATUS.

SPECIFICATION forming part of Letters Patent No. 303,714, dated August 19, 1884.

Application filed Ju To all whom it may concern.-

Be it known that I, I'IORACE H. ELDRED, a citizen of the United States, and a resident of the city, county, and State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems and Apparatus, of which the following is a specification. Y

My invention relates to a method of intercommunication known as the district exchange telephone system, and it consists, in general, ot'a central or exchange station, which is connected with a number ot'sub-stationsby means of telegraphic or telephonic lines radiating therefrom, these latter being so organized and arranged that any two of the substations may be placed at amoments notice in direct telegraphic or telephonic commnnication witheach other by the act of an attend ant at the central or exchange station, who, upon being notified to .do so, connects together the two lines leading to the respective substations, so that they are enabled thereafter to com municatc with each other directly.

My invention consists in the combination,

with a series of telephfonelines converging to a central station from a corresponding number of sub-stations, hereinafter termed substation lines, of a switch -board consisting of a series of spring-jacks-one for each linefor the insertion of wedges or other equivalent devices for effecting changes in the connections of the several lines, and a series of visual signals or annunciators-one for each line-for indicating the particular line or spring-jack with which a connection is required tobe made, one of these visual signals placed on each line at a point between the said springjack and the earth, to which all the lines are normally connected, whereby, when any two independent lines are temporarily disconnected from the earth and coupled 'together to form a combined circuit, their corresponding annnnciators are excluded there- 5 from.

The invention further consists in the combi nation, with the hereinbef'ore-described system of lines converging to a central station, of movable switches and conducting bars or strips united in pairs,with branch or loop conductors at said stat-ion, whereby direct communication can be established between any two substations by connecting their respective lines together at the central station, and

a signalingapparatus included in each of said 5 5 branches, loops, or connecting-conductors, whereby, after having been thus connected together, the two substations or either of them may notify the attendant atthe central station to disconnect the said lines.

The invention further consists in the com- -bination, with the apparatus last mentioned,

of a signal sending and receiving apparatus and a telephone mounted upon an auxiliary or operators table included in aloop-wire,

which wire is provided with a wedge for insertion into a spring-jack placed in any one of the branch, loop, or connecting conductors, together with a switch, whereby said loop may be divided and the leg thereof containing the signaling apparatus and telephone connected with the earth.

v The invention further consists in various details of construction and organization of the apparatus, whereby its efliciency and con; 7

venicnce of manipulation are enhanced, which will beherei nafter more particularlydescribed and claimed.

In the accompanying drawings, Figure lis a theoretical, plan showing the general arrangement of the switch-board and other apparatus at a central station, and embodying my improvements; and Fig. 2 is a sectional view of the spring-jack and wedge which is employed for etiecting the connections at the 8 5 main switch.

In Fig. 1 I have shown, for the purpose of illustrating my invention, a central exchange or station having six independent lines, which connect with different substations.

The apparatus at each of the several substations is arranged in a well-known manner, and consists of an instrument for transmitting and receiving calls, alarms, or signals, to

gether with a transmitting and receiving telephone, which may be separate or may be combined in one instrument, as most convenient. It may be remarked that any convenient number of lines connecting with as many difi'erent' sub-stations may be grouped together in this manner, according to the requirements of the service. The signaling and telephonic appa ratus at each substationis assumed to be con-. nected in the usual manner with the earth, and also by means of its appropriate line-wire with the central station shown in the figures. These several sub-station line-wires are numbered in Fig. 1 of the drawings as 1, 2, 3, 4, 5, and 6. Upon entering the central station each line is extended directly to the switchboard S, which consists of a row of springjaeks, J J J", 850., which are constructed so as to press firmly against corresponding me tallic plates, 0 e", &c., and thus form an electrical connection therewith. Each spring-jack is connected with or attached to one of the separate lines leading to the several sub-stations, and the several springjacks may be 0011- veniently designated by a number corresponding to the one which serves to distinguish that line, as illustrated in the drawings.

I will now proceed to describe the instru mentalities which I prefer to employ for coupling the different wires together at the central station in pairs for direct communication between independent sub-stations. A flexible insulated conductor, M, usually termed a switelrcord, is provided with a terminal or wedge, N, at one of its extremities. The details of the construction of this wedge and the manner in which it is applied to the switch may be best seen in Fig. 2, which represents a sectional view of one of the spring-jacks of the switch with the wedge inserted therein, in order to make a connection between one of the lines and the central conductor.

In Fig. 2, D is a slab of wood or other nonconducting material, to which the parts of the apparatus are secured. The spring-jack J is formed at its upper extremity into a metallic block, which is mounted upon the slab D and secured thereto, and by means of a suitable binding screw is electrically connected with the wire 1, which is united to one of the lines extending to a substation. The contact-plate upon which each spring-jack rests is connected with its own independent annunciator, indicator, or visual' signal W WV WV by a wire, which, after passing through said annuneiator, is joined to the earth-wire 20, which is common to all the lines when normally connected. By this arrangement it will be observed that the annuneiators, indicators, or visual signals are placed between the switchboard or spring-jack and the earth, instead of being between the switch and the line, as has heretofore been the practice. An important advantage gained by this arrangement consists in the fact that when two lines are coupled to gether at the central station for direct communication the annunciators belonging to these lines are thrown out of the combined circuit, and thus the resistance to be encountered in passing through the central station is greatthe room.

nected with one terminal of the spring-jackj" 1y diminished. The spring -jacks may be normallykept firmly in contact with the plates on which they rest either by their own re silieney or by means of springs. The terminal or wedge N has one of its faces,a,formed of metahand the other face,n, of non-conducting material,the former face being electrically connected with the flexible insulated conductor M. When, therefore, the wedge is inserted beneath the spring-jack, as shown in Fig. 2, the previously-existing connectionbetween the li ne-wire 1 and the earth-wi re 20 is interrupted, and the former is placed in connection through the metallic face n of the wedge with the conductor M; butif the wedge be withdrawn the line is automatically and instantly restored to its normal connection with the earth. The opposite extremity of the flexible cord M terminates in a tapering metallic peg, P, which may be inserted with a twisting motion into one of anumber of suitable holes provided for that purpose in the horizontal metallic bars or strips a a, b 1/, 00, which are insulated from each other by the non-conducting base-board, and placed preferably above the spring-jacks upon the switch-board S,as shown in the drawings. These bars are coupled together in pairs, each pair, as a a, being connected by wires 7 8, forming a branch or loop, and having inserted therein one of a series of auxiliary springjacks, jj j and which are mounted upon the operators table A in any convenient part of For example, the bar a is conby a wire, 7, which also passes through a visual signal or annunciator, R,which is operated by an electro-magnet in a well-known manner,so as to display an indicating device when- 6W3! the magnet is traversed by the current. The other terminal of the spring-jack is connected directly with the bar a by another wire. m

Upon or beside the operators table A is placed an apparatus for transmitting and re ceiving calls, signals, or alarms. I prefer to employ for this purpose a magneto-generator operated by a crank, 70, and which transmits a series of successive electrical pulsations alternately of opposite polarity. The bell r, for receiving calls, alarms, or signals, is operated by an clectro-magnet. A telephonic transmitter, T, and a telephonic receiver, t, with the usual switch, which may be automatic or non-automatic,for throwing either the signaling or the speaking apparatus into the circuit at pleasure, is also provided. This apparatus is placed in a looped wire or circuit, one leg of which,h,terminates in one side of a doublefaced wedge, U,while the other leg, h, goes to the lever of a circuit-changer, S, on the operators table A. When this circuit-changer is moved to the right, it completes the loop through the wire h to the opposite face of the wedge U, but when turned to the left, as in the figure, it connnects the leg h of the loop directly to the earth at G.

ICS

The operation of my improved system is as follows: When a call signal is transmitted from one of the sub-stations (say upon the line numbered 1) to the central office, the corresponding annunciator-drop or other visual signal, W V W WV N W, connected with the wire is actuated, notifying the attendant at the switch, who immediately takes one of the flexible conductors M and inserts its wedge N into the spring-jack belonging to that line which is directly beneath the indicator, and the peg l? at its other end into the lower bar, a, of the unoccupied pair of bars, a a. The operator at the table A at the same time inserts the wedge U into the corresponding spring-jack, j, the circuit changer S being normally turned to the left, as shown in the drawings. The effect of this is to connect line-wire No. 1 with the earth at the central station by the way of flexible conductor M, bar a, branch-wire 8, wires h and h, and cir cuit-changer S, including the telephonic and signaling apparatus upon the operators table. The operator then immediately ascertains, by speaking through his telephone, what line the sub-station calling desires to be placed in connection with, and calls out to the switchman (for example) that No. 6 is wanted,whereupon the switchman instantly connects No. 6 with the upper bar or strip, a, by means of another cord, M, with its wedge N and peg 1?, as in the former case, while the table'operator at the same moment turns the circuit-changer S to the right. The two lines, No. 1 and No. 6, are now entirely disconnected from the earth at the central station, and are united directly with each other through the telephonic and signaling instruments in the loop-wire h h. The table-operator now signals the sub-station on No. 6 by means of alternate positive and negative currents transmitted over the line from his magneto-generator, and upon receiving a response to his signals informs him who is connected with him, and this, being heard also on No. 1, informs that substation that the desired connection with his correspondent has been made. draws the wedge U, leaving the two substations in connection with each otherwithout any instrument in the circuit at the central office except the auxiliary annunciator or vis ual signal R in the branch or loop circuit which connects the two lines. As soon as the two sub-stations thus connected have finished their conversation, one or the other of them, by operating the signaling apparatus, produces an indication upon the annunciator R at the central station in the usual manner, whereupon the table operator notifies the switchman to disconnect Nos. 1 and 6 and re store them to their normal position, and this having been done, the entire operation of connection and disconnection is completed.

By the use of my improved system connections and disconnections may be effected in a telephone exchange system with great facility The table-operator now withand convenience, evenwhen the number of lines is very great, inasmuch as I am enabled to divide the work between one or more tableoperators and a switchman without introducing any elements of complication or confusion.

I claim as my invention- 1. The combination, substantially as hereinbefore set forth, of a series of telephonelines converging to a central or exchange station from different sub-stations, a series of spring- 'acksoue for each linefor the insertion of connecting wedges, and a series of visual signals or calling-annuuciators, \V WV N W XV", one of which is placed in each line at a point between its spring-jack and the earth, whereby the annuuciators are cut out while talking.

2. The combination, substantially as hereinbefore set forth, of a series of telephonelines converging to a central or exchange sta tion from different sub stations, movable switches and conductors 7 8, &c., at said central station, whereby direct communication can be established between any two sub-stations by connecting both their respectivelines together, and an auxiliary or supplemental signaling apparatus, R, &c., ineludedin each of said connecting-conductors, whereby the sub-stations so connected, or either of them, may notify the attendant at the central station to disconnect the said lines.

3. The combination, substantially as here inbefore set forth, of a series of telephonelines converging to a central or exchange station from different sub stations, movable switches and conductors at said central station, whereby direct communication can be established between any two substations by connecting their respective lines together, a spring-jack in each of said connectingconductors, an apparatus I for transmitting and receiving calls or signals, and telephonic apparatus included in a loop which is provided with awedge for insert-ion into said spring jack, and a circuit-changer whereby said loop may be divided and the leg containing the signaling apparatus and telephone connected directly with the earth.

4. The combination, substantially as here inbefore set forth, of a switch-board, an auxiliary table, telephonic or electric apparatus located upon said table, and devices for establishing temporary electrical connection between one or more lines centering in i said t ble, communication between sub-stations and the central station or between different substations being established -through the table apparatus.

5. The combination, substantially as here inbefore set forth, of a series of visual indicators at a central station, a series of independent substation lines converging tosaid central station, each passing through its respective indicator, and thence to a normal connection with an earth common to all of said lines, an operators table, and devices for temporarily disconnecting one or more of said lines from. the earth and simultaneously connecting them with said table.

6. The combination, substantially as here inbefore set forth, of a series of sub-station lines converging to a central station, a series of conducting bars or strips permanently connected with an operators table, and devices for temporarily connecting one or more of said lines with said bars or strips.

7. The combination, substantially as hereinbefore set forth, of a series of substation lines converging to a central station, a series of spri1igjacksone for each linea series of conducting bars or strips, and flexible conductors armed with suitable plugs or terminals for temporarily establishing electric connection between one or more of said lines and said bars or strips.

8. The combination, substantially as hereinbefore set forth, of a series of sub-station lines converging to a central station, a series of annunciators or indicatorsone for each linea series of springjacksone for each linea series of conducting bars or strips, and

flexible conductors armed\vith suitable plugs or terminals for temporarilyestablishing electric connection between one or more of said lines and said bars or strips.

9. The. combination, substantially as hereinbefore set forth, of a series of substation lines converging to acentral station, a series of conducting bars or strips, a series of branch or loop circuits, each uniting a single pair of said bars or strips, and means for forming a temporary electrical connection between any two lines and a pair of bars or strips.

10.. The combination, substantiallyas hereinbefore set forth, of a series of conducting bars or strips, a series of branch or loop circuits, each uniting a single pair of said bars 0: strips, a series of spring-jacksone in each branch or loop circuit-a telephonic apparatus,

and a flexible conductor armed with a suitable terminal plug for connecting said apparatus with any of said branch or loop cir cuits.

11. The combination, substantially as here inbefore set forth, of a number of springjacks, a plug for insertion into said springjacks, a switch, central-office instruments, and connections from said instruments to the points of said switch.

12. The combination, substantially as hereinbefore set forth, of a series of sub-station lines converging to a central station, an operators table, devices for temporarily connect ing one or more of said lines with said table, an electric generator, and key and switch mechanism upon said table for connecting said generator and key with any of the lines connected with said table.

13. The combination, substantially as hereinbefore set forth, of a series of indicators with a series of corresponding sprii'ig-jaclzs, each indicator being placed in proximity to its respective springjack.

14. The combination, substantially as hereinbefore set forth, of one or more operators tables, one or more indicators, and controlling mechanism therefor located upon said tables.

15. The combination, substantially as hereinbefore set forth, of a series of independent lines or conductors, one or more branch or loop circuits, one or more central-office instruments, means for uniting anytwo of said lines or conductors with each other through one of said branch or loop circuits, and means for switching one or more central-office instru ments into or out of such branch or loop circuit.

16. The combination, substantially as hereinbefore set forth, of av series of main lines converging to a switch at a central station,tle vices for uniting any two of said lines for oral communication, apparatus included in each line at the central station to indicate a call or signal, and independent devices for connect ing either line to a polechanging apparatus for transmitting outgoing signals.

Signed by me this 28th day of April, A. D. 1880.

HORACE ll. ELDRED.

\Vi tnesses:

\ VM. TROLLER, J12, II. L. Siro'nitn.

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