US895166A - Telephone system. - Google Patents

Description

PATENTED AUG. 4,' 19o8.- y

W. Vw. DEAN. TELEPHONE SYSTEM APPLICATION FILED DBC. 22.1902.

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UNITED STATES PATENT oFFToE..

WILLIAM W. DEAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO KFLLOGG SWITCIIBOAHD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, (TORIORTIOX OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Lettels Patent.

Patented Ang. 4,A 1908.

Application led December 22, 1902. Seal No. 136,095.

To (1Z t/fzom it may concern.'

Be. 1t known that I, WILLLm W. Deax, a

citizen of the Ltnited States, and residing at Chicago, in the county of Cook and State` of Illinois, have invented new and useful Improvements in Telephone Systems, of which the following is a specification.

My invention relates to telephone systems and particularly to the supervisory apparatus associated with the multiple switch connections of the lines at. the central oflice.

It issometimes desirable to use supervisory signals that are negativein character, that is, such as are visible during conversation and are extinguished to give the disconnect indication. It is moreover desirable with such signal to employ a pilot relay that is positivo in character and which becomes lighted when the other signals are rendered inert.

)Iy invention consists in the several features of the line circuit and the supervisory apparatus hereinafter described A and particularly pointed out in the ppended claims.

In the accompanying drawing forming a part of this specification and in which the figure is a diagram of a telephone system embodying my improvements, the same reference characters are used throughout to indicate like parts.

L and I,2 represent telephone lilies extendingr from their respective substations in two limbs 2 and 3 to the central oflice. At the sub-stations, station A for example` a call bell 1t and condenser 5 are preferably permanently connected between the line conductors, while the receiver 6 and transmitter 7 arel in a bridge of the line normally open at the switch-hook S. Any other arrangement or type of common battery sets may be employed. Atthe central otlice a plurality of jacks such as J and J2 are provided for each of the lines, the line conductor 3 being extended through series contacts 9 in each of the jacks to ground while the tip conductor extends through the series contacts 10 thereof and thence by conductor 11 to the line signal S which is joined upon its other terminal by conductor 12 with the central and common battery B. The line signal shown is of the mechanical type preterably such as have a grating 13 in front of the target 1t of the signal. The target is provided with colored strips, preferably white, normally behind the bars of the grating 13 but which when the signal is actuated l are moved into line with the openings in the grating so as to be readily seen. \\'itl1 this arrangement a slight movement of the target serves to give a fulland readily visible signal.

The cord circuit is provided with an answering plug I) and a calling plug P adapted to register with the contact surfaces of the jacks and when inserted to lift the tip springs thereof so as to open the contacts 9 and 10 and thereby cut-oill the ground connection and the signal S. The tip contacts of the plugs are joined by strands t and i2 connected together inductivcly through the plates of the condenser' c, while the sleeve contacts of the plugs are inductively joined by the strands s and s2 and the condenser cf. A supervisory signal Sl of the mechanical type just described has two balancing windings 15 and 1G connected in the conductors 1T and 1S leading respectively from the strands t and s to the grounded and live poles of thehattcry B. similar supervisory signal for the calling end of the cord circuit 1s connected by means of conductor 19 between the strand t" and the grounded pole of the battery B. A relay r has winding 20 connected in a conductor 2 between the live pole of the battery B and the sleeve strand s? of the cord circuit. l pilot lamp or similar signal S* has its circuit completed from the battery B, by conductor 22 through the pilot relay r2, which conductor leads to the spring 23 of said relay r, the. forward contact of which is tact or armature 25 of the signal S", which is connected by conductor 2G with the grounded conductor 17. A third contact 2T is )rovided upon the calling plug I2 and whiclh is adapted to be electrically connected with the ordinary sleeve contact of said plug by means of the test ring or sleeve contact of the jack of the line. A conductor 2S leads from said contact 2T through a retardation coil '29 which is preferably located upon the core of said relay r. The tip strand of the cord circuity is open atv the front contact of spring 30 of `relay r and the forward portion of said strand is connected through said spring and its back contactv with a conductor 31 leading to the high impedance and high resistance test relay r3, the opposite pole of which is grounded. The operators transmitter 32 is connected in a conductor 33 leading from the live pole of battcrv B through a retardation coil 34 to ground. The primary windjoined by conductor 24. with the back coning of the operators induction coil 35 and the condenser c3 are connected in a shunt of the transmitter 32. The operators receiver, the secondary of her induction coil 35 and a condenser are adapted to be bridged across the cord circuit by the springs 36 of any suitable listening key. The generator 3T having one pole grounded is arranged to be connected with the tip side of the cord circuit by the springs 38 of a suitable ringing key while at the same time the sleeve cord is grounded. This connection of the generator serves to operate the call bell located at the station C while a depression of the springs 3D of the ringing key connects thc said generator similarly with the other side ot' the cord circuit to ring the bell at the station D. Owing to the series contacts of thc jacks, no cut-oli relays are required for the lines.

In connecting subscribers for conversation the line signal S is actuated in the usual way by the removal of the receiver at the substation for conversation. Seeing tl.e line signal the operator connects her cord circuit with the line, thereby cutting oli the line signal and the\ground coniiect-ion and causing the opera-tion of the su ervisory signal S through thcniediuin of tiie current from the battery B which is now ilowing over the calling line. Thejwanted line is tested in the usual way. If idle the test rings are connected to ground through the series contacts 9 of the jacks, but if isysuch ground is cut-olf and they are conne vted with the live pole of the battery, whereby the application of the tip of the testing plug permits a flow of current through the test rela-y 11.3 thus energizing the saine and causing it to complete a path for current through the primary windin 1r of the operators induction coil toA cause a cilick in the operators receiver.

Finding the line idle the plug is inserted and the ringing key operated. As before pointed out, either party may be rung by the actuation of the proper springs of the ringing key, the opposite line conductor being grounded to provide a low resistance return path for current in case the subscriber rcspoiidsduring ringing or in case a single subscriber is being rung. After ringing and before the subscribers response the relay r is actuated by current over the sleeve strand, through the winding 20, the sleeve contact, test ring of the jack, contact 2T of the plug and :hence by way of conductor 2S and through the 500 ohm winding 29 of relay 1 to ground. This relay is therefore operated to close the spring 23 upon its forward contact to complete the circuitl at one point of the )ilot relay and to disconnect the test relay by means of the spring 30 and complete the tip strand of the cord circuit for talking. The supervisory signal S3 has not yet rcs onded since there is no current tlowing over tlie metallic line. 'hen lthe subscriber re- 4of the relay r furnishes sufIicient retardation to prevent the, passage of the voice currents. The battery B furnishes current te both lines for transmission purposes and for the operation of the various relays. l.\t the termina- 7 tion of the conversation thc return of the receivers to thc hooksdeprivcs the signals S and S of operating current and the'signals are retired. The restoration ofsignaibi coinfil pletes the circuit of the pilot rclav i which` 50 is now energized to close the circuitof -t-he pilot lamp'S, in response to which thc operator takes down the connection and restores all parts to normal condition. It will thus be observed that av positive pilot signal is ob- 35 tained with the negati c supervisory signals. Of course, the mechanical signals may be replaced by relays and lamps.

Various modilications may be made in my invent-ion and I do not therefore desire to be limited to thcexact features shown and described cxcept when such is made necessary by the specific liinit-ations imposed herein. i

I claim. t

1. 'ln a telephone system, the coinbin'ationl 9 with a telephone line, of a cord circuit to establish conversational circuits' therewith, a supervisory signal associated with cach end of thc cor'd circuit and adapted to be rendeied inert at the termination of the couver 100 sation, and a supervisory signal common to a plurality of cord circuits displayed when the calling subscriber hangs up his receiver and again eflaced when the calling plug is removed from its connection with the called los line, substantially as described. 2. In a telephone system, the combination with a telephone line, of a central source of current, a pilot signal for the cord circuit, a

cord circuit to establish conve `sational circuit-s therewith, a relay connected between the said source and one side of the cord circuit, said rclay serving to control at one point the circuit of the pilot signal, and

means operated when the subscriber replaces his receiver for closing said circuit at ans other ioint, substantially as described. 3. n a telephone system, the combination with a telephone line, of a cord circuit to a central battery connected between the strands of the cord circuit a supervisory signal connected between said battery and one of said strands, a relay connected between establish convcisational circuits therewith,

said battery and the other of said strands,

said relay servingr to control the current path of said signal over its strand, substantially as described 4. Ina telephone systenr` the combination with a telephone line, of a cord circuit to es-"lg Liri-2 sagmal control,

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signal connected with the answering end of the cord circuit and responsive to current over the line, said signal being visible during conversation, a relay actuated over the .calling end of the cord circuit, and a pilot signal havingr its circuit controlled by said relay and said supervisory signal and adapted to be actuated when said signal is rendered invisible, substantially as described.

5. ln a telephonesystem, the combination g with a telephone line, of a cord circuit adapted to be connected therewith for conversational purposes,

a supervisory signal associ- 1 l l l l ated with one end of said cord circuit and 2 adapted to be actuated over the telephone line, a relay associated with the other end of said cord circuit and adapted to be actuated by current in a local circuit, a pilot signal adapted to be displayed when said supervisory signal is in its normal condition and when said relay is in its actuated condition, substantiallyvv as described.

(i. ln a telephone system, the combination with a pair of telephone lines, of a cord circuit adapted to connect said lines together for conversation, supervisory signals for said cord circuit, one under the control of each of the subscribers connected for conversation, a relay associated with the cord circuit and adapted tobe actuated during the connection of the calling end of the cord circuit with the called subscribei"s line, a pilot supervisory signal associated with the cord cir cuit and having its circuit normally open at contacts of said relay and normallyclosed at contacts of said supervisory signal, whereby said pilot signal is displayed only when said supervisory signal is inert and said relay is actuated, substantially as described.

7. In a telephone system, the combination with a `plir of telephone lines having jacks at the centralolliee, of a cord circuit adapted to connect said lines together for conversation, a callingfplug for said Cord circuit a pair f supervisory signals associated with the cold circuit, on" ol said signals being controll yd over the calling subscribei"s line and the other over the` answering subscribe1"s line, a. pilot signal associated pervisory signhls `and adapted to be displayed only when` said signal is inert, and means controlled through contacts of the plug and jack to prevent the display of said )lot signal when the connection is severed between the calling end of the cord circuit and the called telephone line, substantially as described.

S. In a tele )hone system, the combination with a pair oli telephonclines, of a cord circuit adapted [or conversation, a pair of supervisory sigwith one of said sute connect "said lines togethen aitsmaa nals associated, one with each of said lines during the connectionof the cord circuit therewith, said signals being adapted to be positively displayed during conversation and negatively displayed when the conversation has terminated, and a pilot signal associated with the cord circuit and adapted to bc negatively displayed during conversation' and iositively displayed when the conversation ias terminated, and means actuated by the removal of ther calling plugr from the jack for again ellacing the pilot signal, substantially as described.

- Signed by me at Chicago, county of Cook, State of Illinois, this 11th day of December WILLIAM W. DEAN. 'itnesscs:

ROBERT LEWIS AMES, GAZELLE BEBER.

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