US1271322A

US1271322A - Telephone-exchange system.

Info

Publication number: US1271322A
Application number: US16417217A
Authority: US
Inventors: Charles W Keckler
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1917-04-24
Filing date: 1917-04-24
Publication date: 1918-07-02
Anticipated expiration: 1935-07-02

Description

c. WQKECKLER. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED APR. 24. [EU- Patented July 2,1918.

rmm

' Afiy.

S A A NT cries/IT CHARLES w. KECKLEBI, OFYNEWARKVNEW JERSEY, nssreivon r0 wnsrnnnnnncrnrc COMPANY, INCORPORATED, or NEW YGRK, N. Y., A CORPORATION on NEW YORK.

To all whom it may concern: Be it known that'I, GHARLEs VV.;K.E0KLER, a citizen of the United States, residing at 'Newarlqin the county of Essex and State of New Jersey,- have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact dBSCIlPtlOII. This invention relates to telephone ex change systems, and more particularly to such systems of the centralene'rgy type,its object being to improve the service rendered by such systems. c In accordance with a feature of thisinventi on, a "link circuit employed for connecting'together telephone lines terminating at a central office is provided with meansfor automatically connecting an operators tele-. phone set thereto upon connection of the link circuit with a calling line.- Preferably the means employed is an electromagnetic relay common to a plurality of link circuits.-

Inaccordance with another feature of this invention, means are provided for the link circuits by which it is impossible to connect the operatorstelephone set to more than onelink circuit at a time;

'This invention is illustrated in the accompanying drawing in which allapp'aratus is in its normal'p'osition with the 'operators telephoneset disconnected'from-the link circuits; 4

In the-drawing there are shown two ordinarytelephone lines A and B extending from subscribers stations and terrninating at a central office where there are locateda plurality' of link-circuits G and D forinterconnecting the telephone lines. Only so much of the link circuits as is necessary "for a proper understanding of this invention is shown. i 1 I Thegconnection of'an operators telephone .set with the link circuitiscontrolled by a relay 5=common to the link circuits. This relay 5 is in series witha polarized relay 6, across a Wheatstone bridge having three arms common to the li'nkcircuits, the fourth arm being provided in the separate link circuits. The arms common to' the 'linkcin cuitsare 7, 8 and 9'; The resistances of these arms are so proportioned that, when none of the link circuits are inuse, there isfa flow of current'from battery through the contact of key 11 to a point 12 where it divides, a portion going through resistance arm 7 to a I e Specificationof Letters Patent.

App1icati0nfi1edApri124, 1917. Serial No. 164,172.

TELEPHONE-EXCHANGE sYsrnivr, 7

Patented July 2, 1918.

point 18, and another portion going through resistancearnl 8 and the windings of polarized relay 6 and relay 5 to the point 13 and thence through resistance'arm 9' and ground. The polarized relay 6is so poled that-it does not attract its'armature when traversed by current flowing in the direction just traced.

Relay 5, however, is operated,- maintaining the operators telephone set disconnected from the link circuits. When the answering end of any-link circuit, as C, is connected with a telephone line, the resistance 10C is connected with the Wheatstone bridge and forms the fourth arm thereof. The bridge is now balanced and relay 5 releases its armatures, connecting the operators telephone set with the link circuit. Should the answering ends of two link circuits be connected with two telephone lines simultaneously, resistances l0- C and lO-D will be connected in parallel to form the fourth arm of the bridge, and'when so connected the bridge will be unbalanced. Relay 5',will, therefore, be operated, disconnecting the operators telephone set from bothlink-circuits. The direction of flow ofcurrentthro'u h relays 5 and 6 will be such that polarize relay 6 attracts its armature causing the operation of a lamp 14, indicating to the operator that the answering ends of two link circuits have been connected with two telephone-lines, while the calling'end of neither link circuit is engaged. f "y Operation: Assuming that the subscriber of telephone line A has initiated a call in the usual manner, the operator in answering inserts answering plug 25 of the cord circuit G into line jack 26, whereupon answering sleeve relay 27,-vand cutoff relay 28 are operated. The operation of relay 27' connects answering supervisory relay 29 to the talking strands of the cordcircuit, which is thereupon operated to prevent the lighting arethereupon operateda The subscriber of telephone line B may be signaled" in any Well-known manner. The operation of relay 'ssui'scoimee ts"-tlie' conini'oii" circuit leads 35and 36 frcnrthe talking stiaiids of cord circuit C, and also disconnects resistance 10 from the VVheatstone bridge, thereby destroying the balance, and permitting the V i l The eii'ei giz'ation of relay 5 disconnectsthe operators telephone set from the common loads 35 and 36. The operation of relay 33also connectsica'lli1ig .-superyisory relay 89 to the talking strands of cord circuit C, and causes the operation of, calling supervisory. lamp 40. In'gresponse; ,to t he operation of the call bell at station B, the subscriber removes the receiver-from ,the switchhook,thereby causing'gthe operation of the ca li g s u r relay}? to extinguish the calling supervisory lamp-40. At the. conclnsi on' of the conyersation the restoration of the receivers touthe switchhooks causes the denergi-zation of thegsupervisory relays 29*and 39,: Where'- uponihe lamps 3 0 and 40 are lighted to furniish disconnect "signals. 7 The operator may vno;remove theplugs from the jacks, re storing li ll' apparatus to normal.

Should the operator have inserted the a11sWering p*lu-g25 of cord circuit D int-o tl ej ack of another calling line before the calling plug 31- of the cord circuit C was insertedinto the jack 32 of'line D, the resistance 10+Dwould be connected in parallel ryith the resistance :10'C, whereby the resistance-of the fourth arm' of the \Vheatstone bridge circuit would be reduced, destroying the balances Current would then flow frorn -battery through the contact of key ll, ,bridge arm ;7 and the, windings of relays ti andfi'e and the bridge arm 8 in parallel therewith and the resistances, 10-C in parallel 'to ground. 'IZ hecur rent in this path operates relay -5,,thereby disconnecting the operators telephoneyset from the common leads 35 and 36. Polarized relay .6 is also operated, causing the lighting of'the lam p -ld, which is a signal to the operator that theanswering-endsof two cord ,circ uitsha've been connected With two telephone lines, Whilethe calling end of each'ofthe 'cord circuits is not in use. VV'hat isclai nedis: I a telephone exchange system.comprising telephone lines, a plurality of cord rcuits, an operators telephone set, and i a normallyenergized relay "common to the cord circuits denergized uponthe connection 'of o ne end of one of; the 'cord circuits with one telephone line ;to connect there- Withgthi oprators telephone set and energized n'ponthe connection ofthc otherv end of the cord icircuit i ithanother telephone "to disconnect. the 'opera'tors telephone 2; 'A t'lephon"exchangefsysteni dee en "\iiitlr'oii'e er the telephone lines to complete-,-

the fourth arm' of the bridge circuit, and a stritc'hi'ng'device in the bridge responsive to the completion of tvhe fourth arm thereof to connect the operators telephone set with the engaged link circuit.

3. A, telephone exchange systenr comprising telephone lines, a plurality of linlcycircuit's, an, operators telephone set,- a VVheatstone-bridge circuit common tothe link circuits,, mfeans actuated uponconnection. of one of the link circuits with one of thelines to; alter the electrical condition of the Wheatstone bridge-circuit, and a switcl'ring device in' thebridge:responsive to the altered condition thereof to, connect the operators telephone set with the engaged link circuit.

4. A telephone exchange system compris in-g telephone lines, a plurality of link cir-- cuits, an operators telephone set, a VVheatstone bridge circuit having three arms con i'n'on to the circuits, a resistance in each link circuitadapted to form the fourth arm of the bridge, a relay perating upon connection of one of the link circuits with one of the telephone lines to connect the associated resistance with the bridge, and a relayin the bridge responsive to the connection of the resistance with the bridge to connect theoperators telephone set With the engaged link circuit.

5. A telephone exchange system comprisingtelephone lines, a plurality of link cir- Cults including talking conductors forinterconnecting" the lines, an operatofls telephone set, circi'iitleads common to the link circuits and normally connected to the talking conductors thereof, and means common to the link circuits for connecting the operators telephone set to the common circuit leads.

or '6. A telephone exchange system} comprisi-ngtelephone lines, a plurality of link circuits including talking conductors for inte'rconnecting'the lines, .an operatofls telephone set, circuit leads common to the link ing conductors thereof, means coiirmon =to tlie' link :circuits for connecting the operetors telephone set 'to the common circuit leads, and means associated with an cn gaged link circuit for disconnecting the common circuit leads from the vtalking con-.

thereto, c a relay common to the link circuits responsive to the connection of one end of one of the link circuits with a telephone line to connect the operators telephone set with the common circuit leads, and a relay responsive to the connection of the other end of the engaged link circuit with another telephone line to disconnect the common circuit leads from the engaged link circuit.

9. A telephone exchange system comprising telephone lines, a plurality of link circuits, an operators telephone set, a Wheatstone bridge circuit common to-the link circuits, means actuated upon connection of one end of one of the link circuits with one of the telephone lines to alter the electrical condition of the Wheatstone bridge circuit, a switching device in the bridge responsive to the altered condition thereof to connect the operators telephone set with the engaged link circuit, and means responsive to the connection of the other end of the engaged link circuit with another telephone line to restore the VVheatstone bridge circuit to normal condition to thereby disconnect the operators telephone set from the engaged link circuit.

10. A telephone exchange system comprisciated resistance with the bridge, a relay in the bridge responsive to the connection of the resistance with the bridge to connect the operators telephone set with the engaged link circuit, and a relay associated with the second link circuit operating upon connection thereof with a second telephone line to connect its associated resistance with the bridge and in parallel with the resistance of the first link circuit, the relay in the bridge being responsive 'to such connection to disconnect the operators telephone set from the engaged link circuits.

11. A telephone exchange system comprising telephone lines, a plurality of link circuits, an operators telephone set, a'Wheatstone bridge circuit having three arms common to the link circuits, a fourth arm for the bridge connected therewith upon connection of one of the link circuits with one of the telephone lines, and a switching device in the bridge responsive to the connection of the fourth arm to the bridge to connect the operators telephone set with the engaged link circuit.

12. A telephone exchange system comprising telephone lines, a plurality of link cir cuits, an operators telephone set, a Vheatstone bridge circuit having three arms common to the link circuits, a fourth arm for the bridge connected therewith upon connection of one end of one of the link circuits with one of the telephone lines, a switching device in the bridge responsive to the connection of the fourth arm of the bridge to connect the operators telephone set with the engaged link circuit, and means responsive to the connection of the other end of the engaged link circuit with another telephone line to disconnect the fourth arm from the bridge. i

'In witness whereof, I hereunto subscribe my name this 20th day of April, A. D. 1917.

CHARLES W. KE OKLER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washington, D. G.