USRE12156E - Telephone system - Google Patents

Description

RBISSUED SEPT. a, 1901i I J. w. LATTIG & c. L. GOODRUM.

TELEPHONE SYSTEM.

APPLICATION rILnD- we. 20, 1903.

Reissued September 8, 1903.

"UNITED STATES PATENT OFFICE.

JACOB WILLIAM LA'FTIG, OF \VEST BETHLEHEM, AND CHARLES LANEGOOD- RUM, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNORS TO'EASTERN TELE- PIIONE MANUFACTURING COMPANY, OF lVESTCHES'IER, PENNSYLVA- NIA, A CORPORATION OF PENNSYLVANIA.

TELEPHONE SYSTEM.

SPECIFICATION forming part of Reissued Letters Patent N 0. 12,156, dated September 8, 1903. Original No 722.367. dated March l 1903. Application for reissue filed August 20,1903. Saris-1N0. 170.105;

To all whom it mag concern:

Be it known that we, JACOB WILLIAM LAT- TIG,1eSiding at W est Bethleheni,in the county of Lehigh, and CHARLES LANE Goonnon, re-

5 siding at Philadelphia, in the county of Philadelphia, State of Pennsylvania, citizens of the United States, have invented certain new and useful Improvements in Telephone Systems; and we do hereby declare the following to to be a full, clear, and exactdescription of the invention, such as will enable others skilled in the art to which itappertains to make and use the same.

Our invention relates to telephone-exchange.

[5 systems, and has for its object the production of a system such that all the exchange functions may be more perfectly performed bysimpler apparatus than heretofore.

In telephoneexchange systems, even of small size, it is now customary to employ a centralized or common source of electrical energy from which current is derived for use at the subscribers stations as well as at the central station. Such centralization of the power- 2 5 supply has rendered it possible to employ automatic signals throughout-that is, signals which do not require separate acts specially performed by subscriber or operator for their actuation or restoration to normal, but which respond directly to conditions as they are produced or changed in initiating, setting up,- responding to, and terminating at conversational connection.

ing, but simply removes his receiver from its hook and places it to his ear ready to converse and to listen, giving no thought to the signal, which, nevertheless, has responded to his closure of the line-circuit. Then the operator'has set up the desired connection, she need use no switch to ascertain the wishes of thejsubscribers or the condition of the lines by listeningor otherwise,for each co rd-cir'cuit is provided with telltale-signals, (usually two in'number, one for each subscriben) which respo nd faithfully to each change in condition of the line as it is aifected by the use or disuse of the subscribers talking apparatus.

Such systems are called supervisory sys-. 5o toms, the automatic signals aifording an opsimilar. parts ,are pointed out by the' same portunity for constant and perfect supervision Thus in modern I systemsa subscriber performs no special act in call-.

simultaneously of all the connected lines controlled by each operator,-

three-conductor cord but this disadvantage is considered preferable to cutting off in the jack, which is the alternative method. We employ neither method, but avoid the disadvantages of both-by using shunts closedwhen the plugs are inserted. r '70 In most common battery'systenisthe'supervisory signals are'controlled by ordinary neutral magnets which when brought into connection with the lines respond to the flow. of current therein to conceal theirsignals and whendeenergized cause the .display of their signals. Obviously when the cord-circuits are disconnected and out of use some provision must be ma'de to prevent the continued display of the signals. This is usually ac- 8o 'complished either by switches in the plugas supervisory signals might very well have other functions-for instance, replacing linesignals or trunk-signals. lVe desire it'to be expressly understood that we consider ourselves to be thebriginators of this polarized type of signal controlled by the differential action of divisions of asinglc battery or generator or of separate units employed in the same relations.

Other features of our invention will appear hereinafter from thedeseription and'claims.

In; the accompanying drawing, wherein characters throughounthe'figure is a diagram illustrating*ourinvention; v I

In thed'rawing, A and B represent two subscribers stations, each connected to the.

.centralofljce-L'O byline-wires 1.and'2. As these-stations are alikein their equipment and connections, we will describe the station- A for both. At this stationthe litre-wires 1 and 2 a.re normally connected for alternating currents through the condenser P, ringer Q, and switch-hook- H, the hook'being down. When the receiver isremovedfrom the hook,- the hell or ringer circuit is broken and the talking-circuit is completed thro'ughthe transmitter T and the receiver R.

I At the central office the main battery B is connected betweenbus-bars 38 and 539. The line-wire 1 is connected to the bus-bar 39 through the choke-coil8 and wires 'i27 and 28.

Line-wire 2" is connected to the bus-liar 38- through the line-relay winding9, the choke coil 7, and wires and 30. Line-wires 1 and 2 terminate, respectively, in jackf springs 3 and 4 of the spring-jack J A test ring or thimble 6 is also provided in the jack, and this is connected, as shown, to the same thimble in all the multiple jacks of the same line and by stem 5 and wire 29 to' a point a: -intermediate the line-relay 9 and the c hokeFcoil-T. The spring 4 is so positioned with regard to the thimble 6 that when a plug is inserted the sleeve thereof will cross the springi and thim ble ogether. The purpose ofthis will be pointed out later: 1

The resistance of the coil 8 we usually malie we make thirteen hundred ohms, andlof the coil 7 we maketwelvehundred ohms? .Tlie

relay 9 controls an armature 24, which closes on a contact-point 25, connected by wire 26 to the bus-bar 39: The armature or its equivalent, which may be a twin contact to is connected by wire 16 to the line-signal lamp 10 and thence by wire 17 to" the other side of battery at bus-bar 38. It will be understood that these wire connections are not necessarily carried individually to the power-board, but that common wires may form continuations of the bus-bars.

The multiple jacks (representediby J are in every respect duplicates of the jack J and are connected in parallel .therewith to the wires 1, 2, and 29.

Interconnection of the lines for conversation is effected through the cord-circuit 18 19 23 23. This cord-circuit terminates in plugs M M and is conductively divided, but inductively completed by the condenser-s13 and 14.

For continuous cur-rents,therefore, a complete conversation-circuit consist-sof two independent sections which are fed separately. Each I plug M or M is provided with a tip-contact 20, connected to one side, 18 or 19, of. the cord, and with a sleeve-contact '21, connected with the other side, 23, ofthe cord. v

For each cord-circu't t'wo supervisory relays R R are provided. 7 We will describe 'theone,

' call. ing-plug M, by the mere insertion of which three results are produced, viz: The cord-con V R, for both. This consists in the present case of a horseshoe permanent'magnet- 11, having windings upon its two poles of approximately seven hundred and fifty ohms resistance, c'onnected by wires 22 and 34 to the cord-conductor 23 on one side and to bus-bar 340 on the-other. This'bus-bar 340 is a third busbarv of the main battery, being connected thereto at such a point that the difference of potential. between it? and the bus 38 will be much less than that between it and bus 39, the former being, for instance, six volts and the latter thirty-four volts where the total voltage of the main battery is forty. All the.

supervisory relays are connected to this third busba r.. Its purpose will be referred to in the statement of operation.

Pivoted to swing between-the poles of the permanent magnet 11 is an armature 36,which forms one terminal of a normally open circuit 35, whose connection istothe main. bus-bar 39 andwhose continuation 33 passes from bus 38 to a lamp12 and so by Wire 32,130 the contact-point 31,wh.ich lies in the path of the armature 36. A spring 37 gives the armature a normal bias to the right; but it is obvious that this may be accomplished in other ways,

and, in fact, the entire construction of the relay may be varied in a hundred ways without departing from the spirit of the invention. We reserve to ourselves the right to make this relay in any convenient way, therefore.

The operation of the system so described is as follows: The subscriberA,we will suppose, wishes to converse with subscriber B. He removes the receiver R from the hook H, which thereupon rises and closes the circuit through the talking set and permits direct current from the main battery to pass through the following circuit bus bar 39 wire 27 choke-coil 8, wire 28, line-wire 1, talking set R T H, linewire 2, wire 15, relay 9, choke-coil 7, wire 30',

to bus-bar 38"., This energizes. the relay 9,

whichthereupon attracts its armature 24: and

j closes the local-line lamp-circuit as follows:

bus-bar 39, wire 26, point 25, armature 24,wire

16, lamp 10, wire 17 ,to bus-bar 3,8. The lamp 10 then lights, informing the operator of the She responds by inserting the answerductors are brought intoconneetion with the line-wires, the relay 9 is shunted by the wire thus causing the relay-armature v.to fall away and extinguish'the lamp 10, and the supe'rvisory relay is connected to the jack-thimble 6 through the sleeve-conductor of the cord by the following path) to battery: wire 22, cord-conductor 23, plug-sleeve 21, jack-thimble 6, stem 5, wire 29, coil 7, wire 30, to bus 38 and battery B, through the-upper division 40 of the battery to the bus 340, and by wire 34 back to the relay. This current flowing through the relay-coils under an electromotive force'of, say, six volts, if unopposed would suflice to overcome the spring 37 of the armature 36, drawing the latter over to the left and closing on the contact 31, thus lighting the lamp 12 bycurrent flowing in. circuit 39 35 36 31 32 I2 33 38to battery. The lighting of the lamp inanswering the call is prevented, how;

ever, by an opposing current that flows in the following circuit: bus-bar 39, wire 27, coil 8,

7 divided battery connected so that there are calling-plug M 011 oneside by the path 51, K,

bus-bar 340.

opposed electromotive forces through the windings of the relay R, and as they are unequal the resultant-current is ina direction to reinforce the spring 37 and morn) opposeit'. Thus the supervisory lamp. does not light for,

the calling-line! Having received the number wanted, the operator proceeds' to test to determine if the wanted line is free; This she does by throwing over the listening-key K to listening position, andthereby bringing her head-phone into connection with the ti'p'cf the 52, l 9, and 20- and into connection with the bus-bar 38 of the main battery on the other side by the path 53, choke-coil 54 '55 to bus 38. Now when the tip 20 is touched to the thimble 6 of the wanted line, if thesubscriber has called. from station B and has not yet been answered a circuit will be completed from the tip through the thimble 6 to line and back and by conductor 28, coil 8, and wire 27 to the busbar 3.), the current flowing in this circuit producing a characteristic busy click in the operators car. If the subscriber has not answered a previous call, but another operator has already made connection with'his1ine,then a click will be obtained by current in a circuit through the thim ble 6 to the corresponding thimble of the multiple jack alreadyin use and over the sleeve of the plug therein and its cord conductor 23 to the polarized relay R and to If a cord atanother section has already been brought into connection with the v wanted subscribers line and he has answered the call, then both the paths traced will be available and the click will be heard, as a matter of course. If the line is idle, however, no click can be obtained, because the tip 20 and sleeve or thimble 6 will be at the same potential.

It will be observed that connection is made to but one side of the cord from the battery 1 and. a word of explanation is here in place concerning the currenhsupply for talking. The battery has the permanent branches 27 and 30, including the choke-coils 8 and 7, respectively, by which direct current is fed to the lines in parallel, the choke-coils preventing any propagation of the changes due to speech in the battery-bridge, but forcing all speech-currents to go across through the cord from line to line past the battery branches. The branch 22 34 througlwjhe supervisory rc- We thus have a',

lays is solely for the purpose of supplying current to said relays; but ineidently'it also carries part of the line-supply.

The relays R and-R having been described, it will now be understood how they perform their dual function under three conditions.

Each spring "37-is strong enough to keep the we claim, and desire to secure by Letters Patline-circuit interconnecting them, a source of. current at the central station, connected to the line, a spring-jack for the line, a cordcircuit and plugs cooperatingwith said springjack, a polarized-signal magnet connected on one side to one side of said cord-circuit, and on the other side to the said source of current at a point intermediate of its terminals so as divide the available electromotive forceinto two parts, and means at the subscribers station tocontrol the flow of current in the line, whereby the signal is connected to the line and also in a local circuit to be operated by current in one direction from a portion of the source, in making connection to the line, and is thereafter adapted to be'controlled by current in the line in the other direction from the other portion of the source, substantially,

as described.

2. In a telephone-exchange system, a sub scribers circuit and a subscribers station with means to determine the flow of current in the line, asource of current bridged across the line, a spring-jack and a cord-circuit with a plug to cooperate with the spring-jack, a polarized signal-magnet connected from an intermediate point of the source to one side of the cord-circuit, a signal controlled bythe magnet, and means for normally keeping the signal retired, substantially as described.

3. In atelephone-exchange system, a sub-' scribers station andacentralstationandalinccircuit interconnecting them, a source of current connected to the line in a bridge thereof, a cord-circuit for making connection with the line, and a polarized signal-magnet connect ed from an intermediate point of said source of current toone side of said cord-circuit, with means at the subscribers station to determine the flow of current in the line, whereby the said signal-magnet may first receive current from one side of said source as connection is made with the line, to operate the signal, and may receive current from the izo other side of said source at the will of the subscriber, to con trol the signal, substantially as described.

4. In a telephone-exchange system, a subscribers station, a central station, and a linecircuit connecting them, a main battery at' the central station connected in a bridge of the line-circuit, means at the subscribers station to determine the flow of current in the circuit, a terminal device for the line, and

a cord-circuit for making connection therewith, at the central station, and apolarized signal-magnet connected on-one sideto an intermediate point of said main battery, and on the other side to one side of the cord-circuit,

.Whereby the said signal-magnet may be put in circuit with one side. of the line and division of the battery by the act of making connection with the line, andwith the other division of said battery-at the Will of the subscriber, to receive current in one direction or the other, substantially as described.

' 5. In a telephone-exchange system, a line and a bridged battery, a polarized signal-controlling magnet having its windings connected on one side to a point-in the battery intermediate of its terminals, and nearer one terminal than the other, means operable in making connection with the line to complete the circuit of said magnet through the smaller division in the battery, and means under the control of a subscriber to connect the said magnet with the larger division of the bat- .tery, whereby the efiect of the first current may be overcome at will, substantially as de scribed. Y

6. In a telephon e-exchange system, a subscribers station and a central station, and a line interconnecting them, a main battery in a bridge of the lineat the central spring-jack connected to the line, aplng and cordcircnit for making connection therewith, a polarized signal-controlling magnet connected on one side to an intermediate point of the main battery, differences between operable upon inserting the plug in the jack to bring said magnet .into connection on its other side with one division of the line, whereby its circuit is closed to oneside of battery, and further means controlled by the subscriber, to connect the two sides of line together whereby the circuit is closed to the other division, substantially as described.

In testimony whereof we affix our signatures in presence of two witnesses.

JACOB WILLIAM. LATTI G. CHARLES LANE GOODRUM. Witnesses L., A! POTTEIGER, TILLm I. MAOCAULEY.

such that the potential said points and the terminals'of the battery are unequal, and means station, a

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