US646695A - Telephone-exchange system. - Google Patents

Description

N0. 646,695. Patnted Apr. 3, I900. w. n. GHARKY & E. E. CLEMENT. TELEPHONEEXCHANGE SYSTEM.

(Application filed 1m 20, 1898.)

(No Model.)

ms' NORRIS Farms 60.. morauwa. WASHING'KON: n. c.

No. 646,695. Patented Apr. 3, I900. W. D. GHARKY &;'E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

(Application filed Aug. 20, 1898.) .(No Model.) 2 Sheets-Sheet 2.

S SB

WITNESSES THE Noam: PETERS cu, vflo'roumou WASHINGTON. a c.

UNITED STATES.

PATENT @EEICE.

WILLIAM D.. CHARKY, or PHILADELPHIA, PENNSYLVANIA, AND EDWARD E. CLEMENT, OF WASHINGTON, DIsTRICT OF COLUMBIA, AssICNORs TO THE sUN ELECTRIC MANUFACTURING COMPANY, OF NEW JERSEY.

"TELEPHONE-EXCHANGE SYSTEM.

sPEoIEIcATIoNarming part of Letters Patent No. 646,695, dated April 3, 1900. Application filed August 20, 1898. Serial No. 689,120. (No model.)

To all whom it may concern:

Be it known that we, WILLIAM D. GHARKY, residing in the city and county of Philadelphia, State of Pennsylvania, and EDWARD E.

CLEMENT, residin gin the city of Washington, District of Columbia, citizens of the United States, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a specification.

to Our invention relates to systems for tel'ephonic interconnection wherein a central Ofiice or offices is or are provided, subscribers lines radiating therefrom to substations, 1 Where they are provided with telephonic and I5 signaling apparatus.

The invention relates particularly to such systems of this character as are known as divided central or trunking systems, and it constitutes an improvement upon the particular system described and claimed in our joint application for patent, Serial No. 689,119, filed August 20, 1898. .According to the in Vention set forth in said application conversation is carried on overmetallic or series circuit, while signaling is simultaneously permitted to be carried on over multipled 0r phantom circuits. The various steps in connecting and disconnecting subscribers are performed by two (2) sets of operators called, respectively, for convenience, A and B operators. Each A operator is provided with terminal plugs and communicating cords therefor which she uses in the ordinary way for interconnecting subscribers upon her own section. EachB operator, on the other hand,

devotes her entire time and attention to fin-,

ishing connections which ha've'been trunked by the answering A operators at their sectionsthat is to say, the B operators attend 0 to the completion of trunk-calls and to those only, while the A operators attend to all other business. In order to permit the A operators to keep track of the condition of the lines, certain supervisory signaling means are pro- 5 vided. In the application aforesaid said means consist in a polarized relay. In order to apprise the B operators of connections initiated on the trunk-lines of the A operators, trunk-signals have been used. These trunksignals receive the current from the main source through the calling-jack and the answering-plug circuit. In order to prevent this current from operating the supervisory signal before referred to, the expedient of polarization was adopted. The principal change 5 5 in the construction thus described,which constitutes the improvement to be covered in the present application, is the abolition of individual trunk-signals and the consequent permissible reduction of the polarized supervi- 6o sory relay to a simple ordinary low-wound relay. In place of the individual trunk-signals we use in the present system individual operators signals, each of which is common to a number of trunk-terminals. These are arranged to be operated whenever the operators conversation-circuits are crossed without any especial act or thought on the part of either operator.

Our invention is fully illustrated in the ac- 7o companying drawings, wherein like letters and figures of reference refer to the same parts throughout.

In said drawings, Figure l is a diagrammatic View of the circuit connections of two subscribers whose line-terminals are located upon difierent switchboard-sections. Fig. 2 is a detailed view of the circuit at each subscribers station. Fig. 3 is a diagram of the circuits of a number of operators, showing their signals. Fig. 4 is a diagram illustrating the use of a Wheatstone bridge in the signal ing-circuits.

Referring to Fig. 1, X and Y are two suloscribers stations, each provided with a complete telephone set comprising the usual transmitter and receiver. From the middle point of the windings of the receiver A wire 9 is led to the ground and the receiver-windings are interposed between the divided o halves of the secondary winding of the subscribers induction-coil.

The instruments, as shown in Fig. 1,-are

'supposed to be in position for use and the details of their-circuits are not shown; but upon reference to Fig. 2 it will be seen that the line- wires 1 and 2 during the non-use of the instrument and while the receiver is hanging upon the switch-hook are bridged by the circuit of the bell or ringer Q and disconmo j when the plug is in the jack.

nected from the conversation-circuit. \Vhen' the receiver is removed from the hook, however, the levers H and it rise under the influence of a suitable spring and after breaking the bell-circuit make a circuit over the linewires 1 and 2 through the local connections 18 and 19, the secondary U of the inductioncoil and the receiver, the middle point of whose windings is connected to ground through the wire g, and at the same time the local translnitter-circuit 20, including the transmitter and the primary u of the induction-coil, to gether with a suitable battery, is closed.

The line-wires 1 2 and 3 t terminate in jackspringsjj upon the central-olfice switchboardsections. Each pair of line-wires is bridged prior to its connection with the jack-springs by an impedance-coil I, from the middle point of which a wire 5 is led to one winding Z of the line-annunciator L, and thence by the wire 6 to the main battery M and to ground. The annunciator I, is provided with a differential winding Z, one end of which is connected to the wire 6 and the other to the springj, which is adapted to be connected by a collar upon the connecting-plug with a twin springj, from which a wire leads through resistance Rh to ground. All of the apparatus thus described is substantially the same as that in our prior application above referred to.

Each A operator is provided with pairs of plugs P P, plug P having a tip and sleeve 1) and p, which are connected, respectively, to the sleeve and tip of plug P, although this order of connection is not essential, being revel sible, if desired. The plug P also has a collar 13 which is insulated from the tip and sleeve and whose function is to connect the springs The plugs P and P are connected by the cord conductors 7 S. A relay Nis provided for each pair of plugs, its windings being connected in parallel in the two sides 7 and 8 of the plug-cord circuit. By this arrangement the relay will only be energized by currents passing therethrough in multiple. The armature n of this relay is adapted when attracted to close a local circuit 18, containing a suitable battery .9 and a signal, shown as an incandescent lamp n.) Anordinary ringing-key is also provided for each cord-circuit, which upon its actuation connects the circuit of a generator with the plug P. The said plug P rests in a seat which is provided with contact-springs pp, adapted to touch the sleeve and tip contacts of the plug or external rings thereon, respectively, connected thereto, and to thereby continue the two sides of the plugcord circuit 7 8 to the A opcrators listeningcircuit 11 12.

The plugs P P, with their associated apparatus, sutlice for the connection of subscribers whose line-terminals are near together; but where, as shown in Fig. 1, connection is necessary between subscribers upon dilferent switchboard-sections trunk-lines 9 10 are used, each trunk-line terminating at one end in a jack J and at the other end in a plug P All the jacks J of a given group of trunklines which interconnect any one board with another are grouped together before the A operator at the first board, while their plugs P are grouped together before the B operator at the other board. The listening-circuit 11 12 of the A operator terminating in'her telephone set 0 is branched to all these trunklines and also to all the other switchboardsections. Conversely, the listening-circuit 13 14 of each B operator terminating in her telephone O'is branched to the jacks J 2 of all the trunk-lines leading to her board. \Vithin each trunk-jack J a circuit-closer C is provided having a plunger 0, adapted to be depressed under certain conditions by a plug inserted in the jack, to thereby spread apart springs c 0 forming the terminals of the B operators circuit 13 14 and cause them to make contact with anvils c c, constituting terminals of the A operators circuit 11 12. Before each B operator and in proximity to her trunk-terminals a similar switch 0 is provided, having a plunger 0, which upon depression spreads apart springs c and 0 which form terminals of the A operators circuit 11 12, causing them to make contact with anvils 0 0 connected with the two sides 13 14 of the B operators circuit. In proximity to the trunk-plugs P and connected to the B operators circuit is also provided a jack J.

In order that signaling may be carried on between the operators, the following means are provided: A wire 17 is led from the middle point of the windings of the A operators telephone 0 through the battery S and to all the other switchboard-sections. From the middle point of the windings of each B operators telephone 0 a wire 10 is led out. Before each B operator an annunciator is located provided with a shutter a and having its winding 10 connected on one side to wire 16 and on the other to wire 17. Only one of these annuneiators is shown herein; but it will be understood that the wire 16 of each B operator serves as a common connection for all the wires 17 of the A operators at different boards, and, conversely, each wire 17 of an A operator is cross connected through various annunciator-windings to with the respective wires 16.

The operation of our system thus described is as follows: Subscriber X desiring to converse with subscriber Y removes his telephone-receiver R from the hook II, whereupon the latter and its connected lever rise under the influence of the spring and complete the talking-circuit shown in Fig. 2.

Current will then flow from the battery M through the wire 6, the winding Z, wire 5, the two halves of the coil I and the line-wires 1 2 in parallel to the subscribers station and there through the wires 18 19, the two halves of the secondary U and the two halves ofthe receiver-winding, the wire g, and ground back to the battery. The annunciator L thereupon displays its signal and the A operator at that board perceiving the signal inserts the plug P in thejackJcorresponding thereto. Inasmuch as the plug P remains in its seat a talking-circuit is immediately completed without any further act on the part of the operator from the subscribers instrument to her set 0. Having ascertained the connection desired and finding it to be with the subscriber Y, who is located on another board, the A operator removes the plug P from its seat and inserts it in the jack J of the trunk-line leading to the desired board. In so doing the A operator presses the plug P into the jack farther than is required simply to make connection with the jack-springs, the tip of the plug thereby depressing the plunger and spreading the springs c and into contact with the anvils c and 0 A complete metallic circuit is thus established between the A and B' operators sets 0 and O. Incidentally the signaling-circuit through the annunciator A before the B operator and corresponding to the A operator is completed as follows: from the battery S through wire 17, through the split windings of the telephone 0, through the wires 11 12 in parallel, anvils c 0 springs c 0 wires 13 14 in parallel, split windings of telephone 0, wire 16, winding w, wire 15, and back to the battery. The A operator is thus enabled to instruct the B operator directly as to the number of the subscriber wanted, and while in such instructions she gives the number of the trunk-line and of the subscriber wanted the annunciator A performs the function of directing the B operators attention immediately to the proper group of trunk-plugs, and in case the B operator should happen to be temporarily engaged furnishes a continued indication that she has been called by the A operator, to whose board said trunk-lines are extended. Upon receiving her instructions the B operator inserts the plug 1) in the jack J of the subscriber Y. Current will then immediately flow from battery N through Wire 6, winding Z, wire 5, impedance-coil I, and jack J of the called subscriber, through plug P trunk-wires 9 10, jack J plug P, cord connection 7 8, the two halves of the Winding of relay-magnet N, plug P, jack J, line wires 1 ,2, and to ground through the wire 9 of the calling subscriber. This current energizes the magnet N, which thereupon attracts its armature n, closing circuit 1S and displaying the signal it. This apprises the A operator of the insertion of the plug p and immediately upon perceiving the signal n she depresses the calling-key K, which connects the generator through the plug P and the trunk-line to the called subscribers line to ring his bell. The signal a re-' mally disconnected.

flowed back through the connecting-circuit to the calling-subscribers station, is diverted through the line-wires3 4 to ground at the station Y. Currentnolongerpassingthrough the connecting-circuit, the magnet N releases its armature and the signal n is retired, thus apprising the A operator of the fact that the subscriber Y has'answered the call. 7

Referring to Fig. 3, which is a diagram of the instruction-circuits of three A girls and three B girls with their signals, the A girls positions are shown at O, 0 and 0 the symbols which are so lettered being supposed to represent, diagraphically, operators headphones with the caps removed to show the coils 0 and 0. From eachAgirls position to each B girls position (the latter shown at 0, O and 0 extends an instruction-circuit. That from girl 0 is numbered 11 12, and, as clearly shown, it passes to the B girls positions, crossing all their circuits, which are numbered 13 14, 13 14, and 13 14. The circuit from the position 0 is lettered 11 12 and that from position 0 is 11 12 each of these likewise crossing all the B girls circuits at the left of the figure, but all being nor- Conversely to the above the circuits 13 14, 13 14 and 13 14 pass from the head-phones O, 0 and O to the A girls positions, where each of them is carried across or past all the A girls circuits. At the place of intersection of the circuits 11 12 and-13 14 at the right-hand side of the figure we have shown a pair of bent lines, which are intended to represent a switch which may be turned to connect wire 11 with wire 13 and wire 12 with wire 14. In reality these switches, which are lettered C, are made as shown in Fig. 1, where a plunger 0 acts upon springs c and c to cross the operators circuits. These switches are all located at the trunk-jacks on the A sections, but the trunklines are omitted from Fig. 3 and the switches reduced to their simplest elements in order to prevent confusion. Obviously when any switch 0 is actuated the operator 0, 0 &c., has crossed her circuit with that of the corresponding B operator, according to which switch is used. From a point midway of the windings of the telephone 0 the Wire 17 is led out and passes to theB operators positions, where it forms a common return for the annunciator-coils to, 10, and 10 located, respectively, opposite the B girls, whose headphones are indicated at O, 0 and O Similarly a wire 17 passes from the middle point of the windings of operators telephone 0 and forms a common return for the three coils w, 10 and 10 while the wire 17 passes from a telephone 0 to form a common return for-the windings 10 10 and 20 Thus there is an annunciator-coil opposite eachB girl for each A girl. From the middle point of the windings of telephone 0 the wire 16 is led out to form a common return for the three coils w, w, and 20 From the telephone 0 a similar wire 16? is connected to three coils 10, to and @0 while from telephone 0 the wire 16 forms a common return for the coils 10 10 and 10 Now suppose the operator at O is using a trunk-line to actuate the left-hand switch 0 at her position- She thereby connects the wires 11 12 with the wires 13 14, and not only are the telephones 0 and 0 connected on the metallic circuit, but the following circuit is completed: from battery S by wire 17 to telephone O, and thence by wires 11 12 in parallel to switch 0, thence by wires 13 14 in parallel to telephone 0 by wire 16 to the annunciator w, and by wire 17 back to the battery. The annunciator thereupon displays its signal, telling the first B girl that the first A girl is calling her. By manipulating the other two switches O opposite the telephone 0 the first A girl can send current from the batteries S and S at will through the annunciators 10 and 20 Similarly the girl 0 can work any one of the annunciators w, 10 and 20 according to which operators circuit she connects herself with.

The switches 0 enable the B operators to connect their circuits with those of the A operators for further instructions, &c.

Fig. 4 shows in the simplest possible way the distribution of current upon which de pends the operation mentioned. In this figure X and Y are the subscribers stations, having switches H each adapted to ground the line. The cord-circuit, includinga trunkline when a connection has been completed, is shown extending from J to J, and the supervisory signal is indicated by a galvanometer N. Supposing X to have called, current is flowing from battery M through the left-hand line 1 2 and to ground at station X, and thence back to battery. The operators have made the connection from J to J and the subscriber Y has not yet answered-i. 6., he has not yet worked his switch to ground the line. Current from battery M will now find two paths, one from the battery direct to station X and ground via the point J, and the other by way of point J across through the galvanometer N to point J, and then out to station X and ground. The internal resistance of the battery being small, enough current flows through the branch containing the signal to operate the same. hen subscriber Y answers the call by grounding his line, it must be obvious that a true Wheatstone bridge is produced. The galvanometer N is in the bridge-wire, and as long as the resistances of lines 1 2 and 3 1 are approximately the same there will be no current in the bridge when both lines are complete. If either subscriber should hang up his telephone, and thereby remove the ground from his line, we evidently have a break (or an infinite resistance) in one side of the bridge, and whichever side it is the bridge-wire with galvanometer N will receive current. In applying this to the diagram Fig. 1 it must be borne in mind that for signaling purposes the component wires of the metallic circuit 1 2 and 3 4: are one. The cord and trunk circuits are also single conductors, so that for signaling purposes the conditions are exactly as shown in Fig. 4. One advantage of this bridge construction is that whenever both subscribers have finished a conversation and hung up their receivers the magnet N will not respond, but both line-signals will show for clearing out.

Having thus described our invention, what we claim, and desire to secure by Letters Patent, is-

1. In a telephone-exchange system, operators metallic instruction-circuits for conversation normally disconnected, a separate circuit containing battery and a signal extending between the operators, said circuit composed in part of the different instruction-circuits, whereby when an operator connects her instruction-circuit with anothera correspond ing signal is thereby given to the other operator, substantially as described.

2. In a telephone-exchange system a series of metallic instruction-circuits adapted to be crossed at will to permit communication between operators, a series of signaling-circuits cross-connecting the operators in such a manner that each instruction-circuit forms a common return for all the signaling-circuits leading to any operator, together with suitable signals and batteries in said circuits, substantially as described.

3. In a telephone-exchange system operators metallic instruction-circuits adapted to be crossed together at will, and each containing one operators telephone, signaling-circuits, each containing battery and connected to an operators telephone at one end and branched to a number of other operators telephones, together with a signal in each branch, whereby the crossing of one operators instruction-circuit with another will operate the signal indicatory of the first operator in front of the other operator, substantially as described.

4. In a telephone-exchange system, operators divided into two sets, conversation-circuits between each operator of one set and all the operators of the other set, a signalingcircuit associated with and completed through the circuit of each operator of the first set, and branched through annunciators distributed before the operators of the second set to their circuits, whereby when the circuit of an operator of the first set is crossed with that of one of the other set, the appropriate signal before the second operator is automatically displayed, substantially as described.

In testimony whereof we have hereunto set our hands, this 15th day of August, A. D. 1808, in the presence of two witnesses.

WM. D. GHARKY. EDWARD E. CLEMENT.

\Vitnesses:

ROBERT OSBORNE, J12, EMERSON CONRAD.

ICC

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