US827787A - Telephone system. - Google Patents

Description

PATENTED AUG. 7, 1906.

B. R; GORWIN. TELEPHONE SYSTEM. APPLICATION FILED DEO.15, 1904- 2 SHEETS-SHEET 1.

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BIO-827,787. PATENTED AUG. 7, 19.06. E. R. GORWIN. TELEPHONE SYSTEM.

APPLICATION FILED DBO. 15, 1904.

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"UNITED s'rArns ELMER R. CORWVIN,

PATENT orrron OF CHICAGO, ILLINOIS, ASSIGNOR TO MONARCH TELEPHONE MANUFACTURING COMPANY, OF CHICAGO. ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Aug. 7, 1906.

Application filed December 15,1904. Serial No. 236,958.

1'0 alt 1071,0711, it may concern.-

Be it known that I, ELMER R. CoRwIN, a citizen of the United States of America, and a resident of Chicago, county of Cook, and

State of Illinois, have invented a new and useful Improvement in Telephone Systems, of which the following is a specification.

My invention relates to that class of telephone systems in which signals are set before the operators at a manual switchboard b the removal of the receiver of the subscri ers telephone from its hook, energy being thus supplied to the line for all purposes of signaling and speech transmission from a source in the central o'l'lice, and in which the line, if desired, may be terminated in a plurality of line-jacks in a multiple switchboard at the central oflice.

In many standard systems in use at the present time of the general type which I have just indicated the cord and plug circuits of the switchboard are of three conductors. In my system I limit these conductors to two. In many systems involving supervisory lampsignals associated with the plugs of the cordcircuit either a strand in the cord is utilized to energize the lamp upon the plug being placed in use and a relay is associated with the cord-circuit and the lamp-circuit to open the latter upon the answer of the called subscriber, or two sets of relays are employed, two for each lamp, one serving to place the lamp in action upon the connection of a plug with the line and the other to extinguish it upon the answer of the called subscriber. In my system but one relay per supervisorylamp is required, this receiving its energy in series with the line associated with it, and yet in such a manner as not to interfere by the inductance which it containswith the proper transmission of speech over the line, as is true in other systems in which a series-relay is'involved as a function of the cord-circuit.

l /Iy invention is illustrated in the accompanying drawings, in which- Figure 1 illustrates a pair of lines and a cord-circuit adapted to connect them. Fig.

2 illustrates an alternative form of cord-circuit for use with such lines; and Fig. 3 illustrates in a schematic manner the connection of two stations through their lines and the cord-circuit shown in Fig. 1.

Similar characters refer to similar parts throughout the several views.

Referring now to Fig. 1, 1 is a station on a calling-line formed of the limbs 2 and 3. 4 is a station on a called line formed of the limbs 5 and 6'. Upon the removal of the receiver at station 1 from its hook, current will flow from the battery B, through the line-relay 7, over the limb 2, through station 1 to the central office on limb 3, through the contact-piece 8 to the armature 9 of the relay 7, through the contact-piece 10 to the armature 11 of the relay 12 to ground. The relay 7 will thus be energized and by a construction which adapts the armature 9 to make contact with the piece 13 before breaking from the piece 8 a circuit will be closed through the line-lamp 14 before the ground is removed from the limb 3 at the point 8. Current will then flow from the battery B, through the relay 7, the lamp 14 via 13, 9, 10, and 11 to ground. This illuminating the lamp 14 will be a signal to the operator that a call requires to be answered, as the lamp 14 is adapted to be brought to a proper signaling brilliancy by the voltage of the battery B, while in series with the Winding of the re lay 7. The operator in answering by inserting the plug composed of the elements 15 and 16 into a jack, as 17, of the calling-line will energize the relay 12 by current from the battery B over the conductor 18 via the armature 19 and the contact 20 of the relay 21, through the lamp 22, the sleeve 16 of the plug, the sleeve 23 of the jack 17 or another quite like it, similarly connected to and through the winding of the relay 12 to ground. By attraction of its armature 11 this relay will break contact between it and the point 10, which will extinguish the linelamp 14. It will be observed that unless a plug is in a spring-jack of the callingline, as 17 the attraction of the armature 9 has left no path for the current to flow over the line after the setting of the line-signal until the answering of the call by the operator, when this current may again fiow through the line, being, as before, from the battery B, through the relay 7 over the limb 2, through the telephone and to the oflice on .the limb 3, but now passing from this limb by contact of the spring 24 of the jack 17 to the tip 15 of the answering-plug, through the relay 21,

thence by the sleeve 16 of the plug and the bushing 23 of the jack 17 to ground through the relay 12. It will be seen that this se ries of elements includes all three relays 7, 12, and 21. These are all of such nature as to be energized by series current through the line,

the telephone, and themselves and will beaffected as has been particularly described above. :Contact between elements 19 and 20 of the relay 21 will be broken, extinguishing the lamp 22, signifying that the calling subscriber is at his telephone. In addition such a portion of thetotal voltage of the battery will exist and the difierence of potential between the bushing 23 (and others connected to it) and thefearth as is controlled by the drop of potential through the relay 12. This will providecondition s for a busy test later to be described. Upon learning the number of the called subscriber the operator will insert the other plug ofthe cord-circuit (designated asawhole 25) in an accessible jack of the called line, will ring by means of the rin ingkey 26, and upon the answering of the b subscriber, this being shown by the extinguishrnent of the lamp '27, will abandon connection for conversation until such time as the relighting of the lamps 22 and 27 shall indicate the fact that both parties to the conversation have hung up their receivers, whereupon she will disconnect the 'plugs from the jacks. Preliminary, however, to inserting the plug 25 into the jack, as

' 28 of the called line, formed of limbs 5 and 6,

ftheoperator will rnake the usual busy test ,bytouching the tlp of the plug 25 to the ex- ,posed bushing of the jack desired to be taken.

If that jack is one of a line elsewhere con- 'nected with a potential above that of the earth, it;willbe found busy, and a click will be,observed inher telephone. This will be because the ground connection with the operators telephone-receiver 29 enables her to 'percelve the presence of such test-potentials, the circuit when such a click isheard being as follows; Ifthe subscriber whose line is being tested has his receiver from the hook, current will beflowin'g through the relay 30, connected. to ground from the test-bushings of the 1 test bushing w1ll cause current to flow from line, The potential existing at the touched j thetip 31 of the plug 25 through the ringingkey in the manner usual in such circuits, and, as the listening-key 32 is operated at that V through his receiver, but will exist'by current from, the,battery B over the conductor 18, through the contact of the piece 36 with the armature 37 of the relay 38, thence via the ground at the relay 30.

called lamp 27, through conductor 42 and the ringing-key to the sleeve 39, thence to the various testbushings of the called line, and to In the description of this path, beginning with the conductor 18, it is to be understood that the various numerals indicate homologous parts in a distant cord-circuit which is causing the called line to be busy. It will be seen that under the two sets of conditions which may cause the called line to busy test the same result is achieved, and whenever one of them does not exist'the other will, and no unguarded interval will exist at any time. During the operated condition of the listening-key 32 not only will the test conditions described between the tip 31 and the plug 25 and the ground connection of her receiver exist, but the operators telephone-circuit as a whole will be bridged in series with the condenser 40 across the conductors 41 and 42 of the cord-circuit. It will be observed that the release of the listening-key 32 connects the limbs 41 and 42 of the cord-circuit directly through to the terminals of the plug 25 for unimpeded conversation, although during the operation of the -key such conversation could have taken place through the additional path, including the condenser 40, one of which only exists per operators set. The ringing-key 26, which is ofv the usual type, adapted to connect the terminals of the ringing generator G'to the conductors '31 and 39 of the plug 25, also isconnected, through im pedancecoil 43, with the live pole of the battery 'B. When such connection is made by the operation of the ringing-key 26, current will flow from'the battery B through the coil 43 via the sleeve 39 of theplug 25, over the conductor from the jack-bushing to and through the relay'30 to ground. This, by

breaking the contact between the armature 44 and its point 45, will isolate the limb 5 of the line from any connection with the battery or the ground and will thus permit ringingcurrent to pass over the line through the condenser 46 and the" ringer 47 at the called station, again to the central ofliceov'er the limb 6, through'thecondenser 48, again to the ringing-generator 'at its opposite conductor.

There will thus be no tendency to set a false signalbefore the distant operator by an act of ringing on the part of any operator upon any line, as whatever motions might be caused on the part of the armature of the re lay 49, due to accidental conditions of potential, the circuit of the-lamp 50 is open at the contact 45.

Referring now to Fig. 3 and comparing therein the reference characters which it contairis withsimilar reference characters in Fig. 1, a clear idea may be gained of the circuit rela- ,tions' which exist during the time of conversation. Inasmuch as it'is the'oflice of the relays 21 and 38 to respond to a flow of direct current for the control of the supervisory signals, they must be of such dimensions electrically and mechanically as will enable them to indicate with decisiveness Whether or not the receivers of the calling and called subscribers are on or off their hooks. This, however, is a function of direct current flowing through the relays in question. The alternating or otherwise fluctuating currents pro duced by speech at the substations need not flow through these relays, and the best conditions of transmission aresecured when they do not. A suflicient impedance in the relays 21 and 38 for a very large prevention of short-circuiting voice-currents may be accomplished, together with a-low resistance to direct currents, by a sufliciently generous design involving the use of enough iron and copper. The condensers 52 and 53, being relatively transparent to voice-currents, permit conversation between the connected stations.

Fig. 2 illustrates an alternative arrangement of apparatus in a cord-circuit adapted to be used with the line-circuits shown in Fig. 1. All that has been described with reference to the listening-key 32 and its relation to the operators telephone-circuit, the ringing-key 26 and its relation to the giving of a signal to the called subscriber apply equally to the arrangement here shown. The condensers 52 and 53 and the relays 21 and 38 are omitted, however, from this circuit, their offices being served by the re eatingcoils 54 and 55. The repeating-coil 54 has two windings, one of them composed of the conductor (indicated as 56 and 57) outside of the coil, being connected to the terminals 15 and 16 of the answering-plug. The other winding of the repeatingcoil 54 (indicated as 58 and 59) is connected directly in series with one of the windings of the coil 55. The second winding of the latter coil makes eXit as the conductors 60 and 61. The winding connecting the conductors 56 and 57 in the coil 54 establishes such a bridge upon the callingsubscribers line as is established in Figs. 1 and 3 by the relay 21, and the winding connected to the conductors 60 and 61 stands in a similar relation to the line of the called subscriber. As there is no other path, such as that through the condensers 52 and 53 in the other figures, all current circulating in the calling-line must pass through the winding of the repeating-coil 54. In so far as these currents are direct they will energize the core of the repeating-coil, attracting the armature 62, and opening at the point 63 the circuit of the lamp 64, so that during all the time of conversation no path will be provided from the battery B through the lamp 64 to the sleeve 16 of the answering-plug, and thus over the path previously described to permit the illumination of the signal. The clo sure of the armature 62 upon the point 63 at the termination of the conversation will perconstituting a series portion of the called line.

The mechanical construction of the relayarmature 9 shall be such that it responds promptly to controlling changes of energy in its core 7, while the mechanical construction of relay-armature 11 shall be such that it responds sluggishly to controlling changes in its core 12. Armature 9 thus becomes a quick armatureand armature 11 a slow armature. The necessity for this arrangement of armature speeds arises from the condition of circuits permitting the relighting of the signal-lamp 14 after the withdrawal of the connecting-plug if contact 10 11 should close before contact 9 13 has opened. With this arrangement of armature speeds the sequence of events following the disconnection of the plug from the jack is as follows: Quick armature 9 makes contact 8 9, then breaks contact 9 13. Then slow armature 11 makes contact 10 11, and all parts remain in their normal position.

While I have herein shown and particularly described specific connections for the condensers inthe line-circuits and particular forms of signaling circuits and devices, I do not wish to be limited in all embodiments of the invention to the precise apparatus specifically illustrated.

It is obvious that various changes may readily be made in the system of the invention herein shown without departing from the spirit of my invention.

Having thus described my invention, what I claim is 1. In a telephone system, the combination with two telephone-substations and their connecting-lines, of relays and condensers so arranged as to give a conversation condition in which the line-relay, cut-oil relay and supervisory-relay in series with each other and with the line and substation equipment furnish path for current-supply for that line to which the relays pertain, and in which path for the fluctuating speech-currents passing from line to line is furnished through condensers but not through any winding of any relay, substantially as described.

2. In a telephone system, the combination with two telephone -substations and their connecting-lines, of relays and condensers so arranged as to give a conversation condition in which the line relay, cut-off relay and supervisory relay, in series with each other and with the line and substation equipment 1 with each other,substantially as described.

cut-oil relay adapted to e'l'lace the visual sigfurnish path for current-supply for that line to which the relays pertain, the line and cutoil relays being permanently parts of the equipment of the line, and the supervisory equipment being a part of the equipment of the cord-circuit used to connect the lines, and in which path the fluctuating speechcurrents passing from line to line is furnished through condensers but not through any winding of any relay, substantially as described.

3. In a telephone system, the combination of a telephone-line, a line-relay adapted to give a visual signal when the circuit of said line is closed at the substation and as long as no plug is inserted in any jack of the line, a

nal when a plug is inserted in a ack of the line, the windings of the two relays being permanently connected to one of the conductors of the line, a condenser inserted in the conductor of the line between the point of connection of the line-relay and the point of connection of the cut-off relay, and a ground upon the remaining conductor of the line through a contact of the cut-oil relay, substantially as described.

4; In a telephone system, the combination of a telephone-line having line and cut-ofl relays, with a cord-circuit plug having a supervisory relay, giving a circuit for the supply of current to the line, through the line-relay, cut-oil and supervisory relays, the two members of the line and the telephone-substation, all of the parts named being in series with each other, substantially as described.

5. In a telephone system, the combination of two telephone-lines each having line and cut-off relays, with a cord-circuit having two supervisory relays, forming circuits, when connected, for supply of current to each line from a common current source through the line and cut-off relays of that line, the supervisory relay pertaining to that lines plug, the two members of that line and the substation-telephone of that line, all in series 6. In a telephone system, the combination of .two telephone-lines each having line and cut-ofl' relays, with a cord-circuit havingtwo supervisory relays, forming a circuit, when connected, for supply of current to each line from a common current source through the line and cut-off relays of that line, the supervisory relay pertaining to that lines plug, the two members of that line and the substation of that line, all in series with each other, and forming a circuit, when connected, for the passage of fluctuating speech-currents from line to line through condensers but not through the winding of any relay, substantially as described.

7. In a telephone system, the combination of a telephone-line with multiple jacks,- a

to ground through the winding of a cut-ofi" relay permanently connected between the test-rings and ground; and a second busytest circuit extending from ground through a battery, a winding of a relay 49, the limbs of the-line and the substation-telephone, the

jack, the tip of the plug, the two talking-conductors of the connected cord and a bridged supervisory relay, and the sleeve of the plug, to the test-ring of the jack, and extending thence as in said first busy-test circuit to ground through the winding of a cut-off relay permanently connected between the test-rings and ground; said two busy-test circuits being alternative, the first being complete when the circuit between the linelimbs at the substation-telephone is open and the second being complete when the circuit between the line-limbs at the substationtelephone is closed, substantially as described.

8. In a telephone system having telephone-lines with multiple jacks, the combination of a busy-test circuit a portion of which at all times is formed by the circuit from the test-ring of the multiple jacks of a line through the cut-0H relay to ground, said busy-test circuit being completed prior to the answering of the called subscriber through circuits local to the telephone central office, and after the answering of the called subscriber through circuits involving telephone-substation apparatus, substantially as described.

9. In a telephone system having telephone-lines with multiple jacks, the combination of a busy-test circuit a portion of which at all times is formed by the circuit from the testrings of the multiple jacks of a line through the cut-ofl' relay to ground, said busy-test circuit being completed rior to the answering of the called subscri er by a circuit entirely local to the central o'l-Iice and including one of the conductors of the connecting cordcircuit, with means by which upon the answering ofthe called subscriber the busy-test circuit is changed automatically to be completed throughthe two conductors of the connecting cord-circuit, the supervisory relay, the two limbs of the line, the substationtelephone and the line-relay, substantially as described.

10. In a telephone system having telephone-lines with multiple jacks, the combination of a busy-test circuit a portion of which at all times is formed by the circuit from the test-rings of the multiple jacks of a line through the cut-off relay, said busy-test circuit being completed prior to the answering of the called subscriber by a circuit entirely local to the central ol'lice and including one of the conductors of the connecting cordcircuit, with means by which upon the answering of the called subscriber the busytest circuit is changed automatically to be completed through the two conductors of the connecting cord-circuit, the supervisory relay, the two limbs of the line, the substation-telephone, and the line-relay, substantially as described.

11. In a telephone system with multiple jacks, the combination of a busy-test circuit existing prior to the answering of the called subscriber, said circuit comprising one of the conductors of the connecting cord pair, the cut-off relay and other connecting parts, with means operative upon the answering of the called subscriber by which said busy-test circuit is destroyed and a current-supply circuit established for the substation-telephone through the line-relay, the two limbs of the line and the substation-telephone, the two conductors of the connecting-plug and its supervisory relay and the cut-oii relay of the line, said current-supply circuit forming also a busy-test circuit for said lines multiple jacks, substantially as described.

12. In a telephone system having telephone-lines with multiple acks, the combination of a telephone-line and substationtelephone, the multiple jacks of said telephone-line,a line-relay, a cut-0H relay, a plug adapted to connect with any one of said multiple jacks, circuits associated with said plug, and a busy-test circuit existing when said plug is inserted into any one of said multiple jacks, said busy-test circuit being at all-times partly in a circuit from said multiple jacks through said cut-off relay, and adapted to be completed either through said circuits associated with said plug, or through said line-relay, telephone-line and substationtelephone and the said circuits associated with the said plug, alternatively, substantially as described.

13. In a telephone system having telephone-lines with multiple jacks, the combination of a telephone-line and substationtelephone, the multiple jacks of said telephone-line, a line-relay, a cut-off relay, a

plug adapted to connect with any one of said multiple jacks, circuits associated with said. plug, a busy-test circuit existing when said plug is inserted into any one of said multiple jacks, said busy-test circuit being at all times formed. partly of a circuit from said multiple jacks through said cut-off relay, and adapted to be completed when the substation telephone-circuit is open through said circuits associated with said plug, and means adapted to change said busy-test circuit automatically when the substation-telephone circuit is closed to be completed through the line-relay, the telephone-line and substation-tele hone, and the circuits associated with sai plug, substantiallyv as described.

14. In a telephone system having telephone-lines with multiple jacks, the combination of a telephone-line and substationtelephone, multiple jacks. connected with said telephone-line, testrings forming parts of said multiple jacks, a cut-off relay, circuits from the said test-rings to and through the said cut-ofl relay, a line-relay, a plug adapted to connect with any one of said multiple jacks, a plug-circuit of two conductors connected to said plug, a bridged supervisory relay and a signal device, and a busy-test circuit when said plug is inserted into any one of said multiple jacks, a portion of said busytest circuit being at all times formed by the circuit from the test-rings of said multiple iacks to and through the cut-off relay, said busy-test circuit being adapted to be completed when the substation-telephone circuit is open through the signal device and one of the said two conductors of said plug-circuit, and adapted to be completed when the sub station-telephone circuit is closed through the line-relay, the telephone-line and substation-telephone and the circuits associated with said plug, substantially as described.

15. In a telephone. system, the combina tion of a telephone-line and substatiomtelephone, multiple jacks connected with said telephone-line, a plug adapted to connect with any one of said jacks, circuits associated with said plug comprising two conductors and a bridged supervisory relay, a line-relay adapted to give a visual signal when the substation-telephone circuit is closed, a cut-off relay adapted to efface the line-signal when the plug is inserted into any jack of the telephone-line, and a source of current, the line and cut-off relays being permanently connected to the telephone-line and adapted to connect said line permanently to said source of current and adapted when said plug is inserted into any one of said jacks to complete a circuit for current from said source through said telephone-line and substation-telephone and said circuits associated with said plug, comprising two conductors and a bridged supervisory relay, substantially as described.

16. In a telephone system, the combination of the battery B, relay 49, the two limbs of a telephone-line, the substation telephone,

relay 38 and relay 30, all being connected in having three relays, one relay as 21 or 38 of each line being of high impedance and the two remaining relays of each line being connected in series with each other, with the high-impedance relay and with the line, with two condensers 52 and 53 connecting the two lines at the terminals of the high-impedance relays, and with a condenser as 48 or 65 for each line connected about the two remaining relays of each line, adapted to form a speechtransmission circuit between the two substation-telephones through the four condensers but not throu h the winding of any relay, substantially as escribed.

.18. In a telephone system, the combination of two substation-telephones and two telephone lines connected. therewith, each having'a source of'current and three relays,

Inanently to the two limbs of said line, mu1ti ple jacks connected with said telephone-line, test-rings connected with said multiple jack's,' aplug adapted to connect with said multiple onerelay as 21 or 38 of each line beingof high impedance and the two remaining relays of each line being connected in series with each other, with the high-impedance relay and with the line, with two condensers 52 and 53 connecting the two lines at the terminals of the high-impedance relays, and with a condenseras 48 or for each line connected about. the two remaining relays and the source of current of each line, 'adapted to form a speech-transmission circuit between the two substation-telephones through the four condensers but not through the winding of any relay, substantially as described.

19,. The combination in a telephone sys tem, of a telephone-line of two limbs, a substation-telephone, two relays connected perjacks, conductors associated with said plug, a signal 5 device connected with said plug, a source of electric potential, a test-circuit when the substation-telephone circ uit'is open and said plug is connected with one of said multiple jacks adapted to give testcurrent from said battery through said signal device and conductors of s aid plug to the test-rings of the, m ultiple jacks, a test-circuit when the substation-telephoneis closed, and said plug is connected with one of said multiple acks, adapted to give test-current from said battery through one of saidrelays, the two limbs of said linefthe substation-telephone and the conductors associated'with said plug to the test-rings ofthe jacks, and means adapted to change the test condition from the one testcircult to the other as the substation-tele phone circuit may beopened or closed,'sub

stantially as described. I

.20. The combination in a telephone sys 'tem of a telephone-line of two limbs, a sub station-telephone, two relays connected p'ermanently to the two limbsof saidline, multiple jacks connected with said telephone-line, test-rings connected with'said multiple jacks,

a plug adapted to connect with said'multiple jacks, conductors associated with plug, a source of electric potential, a test-circuit when the substation telephone circuit is open and said plug is connected with one of said multiple jacks adapted to give test-current from said battery through conductors of said plug to the test-rings of the multiple jacks, a testeircuit when the substation telephone is closed and said plug is connected with one of saidmultiple acks adapted to give test-current from said battery throughone of said relays, the two limbs of saidline, the substation-telephone and the conductors associated with said'plu'g to the test-rings of the jacks, and means adapted to change the test condi tion from one test-circuit to the other as the substation-telephone circuit may be opened or closed, 'substantially as described.

21. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means'at the exchange for uniting lines in conversationflineand supervisory or disconnect signal circuits, and condensers in talking sides of said telephonedinesserving to separate said signaling circuits.

22. A telephone-exchange system including a' plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines'for conversation, line-signal and cut-ofl relay circuits, and condensers in talking sides of said telephone-lines serving to separate said line-signal and cutoff relay-circuits.

23. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, line and supervisory or disconnect signal circuits, condensers in talking sides of said telephone-lines serving to separate said signaling-circuits, and cut-off relays for the telephonelines each adapted for inclusion, bysaid conn'ecting'means, in a supervisory or disconnect signal circuit.

24. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting cuits including relays, and condensers in talking sides of said telephone-lines serving to separate s aidline-signal and cut-off relay circuits. I u i 26. A telephone-exchange system includ- III) ing a plurality of telephonedines extending I from substations to an exchange, connecting means at the exchange for uniting lines in conversation, line and supervisory or disconnect signal circuits, said line-signal circuits including line-relays, and condensers in talking sides of said telephone-lines serving to separate said signaling-circuits. 1

27. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines for conversation, line-signal andcutbfi relay circuits, said line-signal circuits including linerelays, and condensers in talking sides of said telephone-lines serving to separate said linesignal and cut-oft relay circuits.

28. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, line and supervisory or disconnect signal circuits, said line-signal circuits including line-relays, condensers in talking sides of said telephone-lines serving to separate said signaling-circuits, and cut-off relays for the telephone-lines each adapted for inclusion, by said connecting means, in a supervisory or disconnect signal circuit.

29. A telephone-exchange system includ ing a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, line and supervisory or disconnect signal circuits each including a relay, and condensers in talking sides of said telephone-lines serving to separate said signalingcircuits.

30. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, line and supervisory or disconnect signal circuits each including a relay, condensers in talking sides of said telephonelines serving to separate said signaling-circuits, and cut-ofi relays for the telephonelines each adapted for inclusion, by said connecting means, in a supervisory or disconnect signal circuit.

31. A telephone-exchange system including a plurality o'f telephone-lineS extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, a line-signal circuit and an additional signal-controlling circuit for each telephone-line and connected with the same talking side of the telephone-line, and a con denser in said talking side of each telephoneline located between the connections of the corresponding circuits with the corresponding talking side of the corresponding telephone-line.

32. A telephone-exchange system including a plurality oftelephone-lines extending from substations to an exchange, connecting means at the exchange ior uniting lines in conversation, a line-signal circuit and an additional signal-controlling circuit including a cut-oii relay for each telephone-line and connected with the same talking side of the telephone-line, and a condenser in said talking side of each telephone-line located between the connections of the corresponding circuits with the corresponding talking side of the corresponding telephone-line.

33, A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, a line-signal circuit including a relay and an additional signal-controlling circuit for each telephone-line and connected with the same talking side of the telephoneline, and a condenser in said talking side of eachtelephone-line located between the connections of the corresponding circuits with the corresponding talking side of the corresponding telephone-line.

34. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, a line-signal circuit including a relay and an additional signal-controlling circuit including a cut-oii' relay for each tele phone-line and connected with the same talking side of the telephone-line, and a condenser in said talking side of each telephoneline located between the connections of the corresponding circuits with the corresponding talking side of the corresponding telephone-line.

35. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, line and supervisory or disconnect signal circuits, and condensers in talking sides of said telephone-lines serving to separate said signaling-circuits, said circuits corresponding to each telephone-line includ-- ing a source of current common thereto.

36. A telephone-exchange system incluling a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines for conversation, line-signal and cut-off relay circuits, and condensers in talking sides of said telephone-lines serving to separate said line-signal and cut-oil relay circuits, said circuits corresponding to each telephone-line including a source of current common thereto.

37. A telephone-exchange system. including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, line and. supervisory or disconnect signal circuits, condensers in talking sides of said telephonelines serving to sepa- IIC IIS

I rate said signaling-circuits, and cut-oil relays for the telephone-lines each adapted for inclusion, by said connecting means, in a supervisory or disconnect signal circuit, said circuitscorresponding to each telephone-line including a source of current common thereto.

38. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, line and supervisory or disconnect signal circuits including relays, and con densers in talking sides of said telephonelines serving to separate said signaling-circuits, said circuits corresponding to each telephone-line including a source of current common thereto.

39. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, line-signal and cut-o'fi" relay circuits including relays, and condensers in talking sides of said telephone-lines serving to separate said line-signal and cut-oil relay circuits, said circuits corresponding to each telephone-line including a source of current common thereto.

40. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, line and supervisory or disconnect signal circuits, said line-signal circuits including line relays, and condensers in talk ing sides of said telephone-lines serving to separate said signaling-circuits, said circuits corresponding to each telephone-line including a source of current common thereto.

41. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines for conversation, line-signal and cut-ofi relay circuits, said line-signal circuits including line-relays, and condensers in talking sides of said telephone-lines serving to separate said line-signal and cut-oil relay circuits, said circuits corresponding to each telephone-line .in cluding a source of current common thereto.

42. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, line and supervisory or disconnect signal circuits, said line-signal circuits including line-relays, condensers in talking sides of said telephone-lines serving to separate said signaling-circuits, and cut-off relays for the telephone-lines each adapted for inclusion, by said connecting means, in a supervisory or disconnect signal circuit, said circuits corresponding to each telephone-line including a source of current common thereto.

43. A telephone-exchange system includ ing a plurality of telephonedines extending from substations to an exchange, connecting means at the exchange for uniting lines-in conversation, line and. supervisory or disconnect signal circuits each including a relay, and condensers intalking sides of saidtelephone-lines serving to separate said signalingcircuits, said circuits corresponding to each telephone-line including a source of current common thereto.

44. A telephoneexchange system includinga plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting linesin conversation, line and supervisory or disconnect signal circuits each including a relay, condensers in talking sides of said telephonelines serving to separate said signaling-circuits, and cut-oil relays for the telephonelines each adapted for inclusion, bysaid connccting means, in a supervisory or disconnect signal circuit, said circuits corresponding to each telephone-line including a source of current common thereto.

45. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, a line-signal circuit and an additional signal-controlling circuit for each telephone-line and connected with the same talking side of the telephone-line, and a con denser in said. talking side of each telephoneline located between the connections of the corresponding circuits with the corresponding talking side of the corresponding telephoneline, said circuits corresponding to each telephone-line including a source of current common thereto.

46. A telephone-exchange system includ ing a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, a line-signal circuit and an additional signal-controlling circuit including a cut-oil relay for each telephoneline and connected with the same talking side of the telephone-line, and a condenser in said talking side of each telephone-line located between the connections of the corresponding circuits with the corresponding talking side of the corresponding telephone-line, said circuits corresponding to each telephone-line including a source of current common thereto.

47. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, a line-signal circuit including a relay and an additional signal-controlling circuit for each telephone-line and connected with the same talking side of the telephoneline, and a condenser in said talking side of each telephone-line located between the connections of the corresponding circuits with the corresponding talking side of the corresponding telephone-line, said circuits corresponding to each telephone-line including a source of current common thereto.

48. A telephone-exchange system including a plurality of telephone-lines extending from substations to an exchange, connecting means at the exchange for uniting lines in conversation, a line-signal circuit including a relay and an additional signal-controlling circuit including a cut-off relay for each telephone-line and connected With the same talking side of the telephone-line, and a condenser in said talking side of each telephoneline located between the connections of the corresponding circuits With the correspond ing talking side of the corresponding telephone-line, said circuits corresponding to each telephone-line including a source of current common thereto.

49. In a telephone-exchange system, the combination With telephone-lines extending from substations to an exchange, means for from substations to an exchange, means for connecting telephone-lines in conversation, signalcircuits corresponding to each telephone-line, and a condenser in one side of each of said telephone-lines serving to separate the corresponding signaling-circuits, said signaling-circuits including a common source of current. a D

Signed by me at Chicago, county of Cook, State of Illinois, in the presence of tWo Witnesses.

ELMER R. OORWIN.

Witnesses:

EVA A. GARLOOK, DAVID S. HULFISH

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