US1337297A - Telephone-exchange system - Google Patents

Description

H. W. ULRICH.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED MAY1I,1918.

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Patented Apr. 20, 1920.

UNITED STATES PATENT OFFICE.

HORACE W. ULRICH, Oi EAST ORAIEGE, NEVT JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPENY, INCORPQRATED, 6F NEE/ YORK, N. Y A CORPORATION OE NEW YORK.

TELEPH ONE-EX CHANG-E SYSTEM.

assass n Application filed May 11, 1918.

To a "whom it may cont-cm.

Be it known that I, Henson "W. ULRICH, a citizen of the United States, residing at East Grange, in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in Telephone EX- change Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone eX- change systems, and morev particularly to such systems employing trunk circuits for completing connections between telephone lines terminating at different switchboards.

in object of this invention is the provision of improved signaling means for such systems.

In accordance with this invention, a trunk circuit is provided with a signal control relay whose operating circuit is partially established upon connection being made with the incoming end of the trunk circuit, and is coi'upletcly established upon the disconnection of a linl: circuit from the outgoing end, thereby to cause the operation of a signaling device associated with the link circuit connected with the incoming end.

For a more complete understanding of this invention, reference should be had to the following description considered in connection with the accompanying drawing illustrating one embodiment thereof.

As shown in the drawing, a telephone line A extends to and terminates at a switchboard at which is located a link circuit B, which may be connected with the telephone line A in any suitable and well-known manner. A trunk circuit C extends from this first switchboard to a second switchboard at which is located a link circuit D for estabishing connections between the trunk circuit C and a telephone line E terminating at the second switchboard. The link circuits B and D may, of course, be employed for interconnecting telephone lines similar to those which are shown terminating at the respective switchboards. The apparatus shown to the left of the dotted line 1-1 is located at the first switchboard which may be designated as X, and that shown to the right of this dotted line may be located at the second switchboard designated as Y.

The operator at switchboard X having actuated the listening key 6 to connect the telephone set with the calling telephone line Specification of Letters Patent.

Patented Apr. 20, 1920.

Serial No. 233,824.

A, receives instructions that connection is desired with a telephone line, for example, line H, which terminates at the switchboard Y. The listening key 6 may then be restored to normal position and plug 7 of the cord circuit B inserted in jack 8 of the trunk circuit C. Lamp 9 lights, and relay 10 and cutoti' relay 1?) operate ov r a circuit from battery through the lamp 9, winding of re lay 10, sleeve contacts of the plug 7 and the jack 8, and the winding of cutoff relay to ground. Relay 10, in operating, causes the energization of ringing relay 11 ov r a circuit from battery through resistance 12, winding of ringin relay 11, normal contact of relay 16, contact of trip relay 13 and the contact of relay 10 to ground. Ringing rell, upon being energized, connects the source of ringing current 14 with the trunk circuit for causing the operation of relay 56 over a circuit from the source of ringing current 14.- through the winding of trip relay 13, lower alternate contact of ringing relay 11, ring contacts of the plug 7 and the jack 8, lower normal contact of relay 17, condenser 18, normal contactand winding of relay 56, the lower contact of relay l9 and resistance to ground. Relay 56, in op erating, completes a locking circuit for itself from battery through the upper alternate contact and windin of relay 16, the lower contact of relay l9 and resistance 20 to groin d. The operation of relay 56 also causes lamp 21 to be lighted to furnish a si nal to the operator at the switchboard Y. 1 operation of the cutoff relay 15 disconnects line relay 22 from bridged relation to the talking conductors of the trunk circuit C.

The operator at switchboard Y, upon obsewing the lighted condition of the lamp 21, inserts plug 23 of cord circuit D into jack 2% of the trunk circuit C, whereupon relay 1S! and marginal relay 25 operate over a circult from battery through lamp 26, normal contact of supervisory relay 27, sleeve contacts of the plug 23 and the jack 24, and the windings of relays 19 and 25 to ground. The operation of relay 19 opens its lower contact, thereby releasing relay 56 to extinguish the lampZl. The closure of the lower contact of relay 25 connects resistance 28 in series with supervisory relay 29. to provide a low impedance path for ringing current for causing the operation of trip relay 13. This circuit may be traced from the source of ringing current 14: through the winding of trip relay 13, lower alternate contact of ringing relay 11, ring contacts of the plug '7 and the jack 8, lower normal contact of relay 17, winding of supervisory relay 29, lower contact of relay 25, resistance 28 and the upper normal contact of relay 17 to ground. Trip relay 18, upon operating, opens the short circuit about the winding of relay 16, which in turn is energized to open its normal contact in the previously mentioned short circuit, and to close its alternate contact, thereby establishing a short circuit about the winding of ringing relay 11 and providing a locking circuit for itself. Ringing relay 11 immediately releases its armatures, disconnecting the source of ringing current 14 from the trunk circuit. I

Upon the closure of the normal contacts of ringing relay 11, supervisory relays 29 and 33 operate over a circuit from battery through the winding of supervisory relay 33,

lower normal contact of ringing relay 11, ring contacts of the plug '7 and the acl; 8, lower normal contact of relay 17, winding ofisupervisory relay 29, lower contact of relay 25, resistance 28 and the upper normal contact of relay 17 to ground. Superrisory relay 33, in operating, establishes shunt circuit including resistance 12 about the lamp 9, thereby extinguishing lamp. Supervisory relay 29, in operati opens the short circuit about the winding of relay 17, whereupon this relay operates oi'er a circuit from battery through the upper contact of relay 19, resistance and the wind ing of relay 17 to ground. Upon the operation of relay 17, the normal contacts thereof are opened, and the alter ate contact closed, whereupon supervisory r lays 33 and 29 are maintained energized over a circuit from battery through. the winding of relay 33, lower normal contact of ringing relay 11, ring contacts of the plug 7 and the jack 8, lower left-hand winding of repeating coil 35, winding of supervisory relay 29, lower contact of relay 25, resistance 28, alternate contact of relay 17, upper lefthand winding of repeating coil tip contacts of the jack 8 and the plug 7, and the upper normal contact of ri gin 11 to ground. The operation oi? re the closure of its upper contact, eireo partially establishing an operating ('11 n1 for relay 36. The winding oi this relay 3 is normally short-circuited through tl middle normal contact of relay 1?, and whilrelay 17 is operated, he short circuit about the winding of relay 36 is maintainer through the alternate contact of sin ervisory relay 29, which operates prior to the operation of relay 17. The insertion or the plug 23 into the jack 24: also causes the operation (DID GB operator may thereupon actuate 1 of cord and trunk supervisory relays 27 and 37 over a circuit from battery through the winding cl supervisory relay 2? contacts of the plug 23 and the 3' lower right-hand winding of the re coil left-hand low resistance winding 0 the trunk supervisory relay 3?, left-hand contact of relay 86, upper rightl1and winding of repeating coil 35 and the tip contacts oi? the jack 2% and the plug 23 to ground. The operation oi cord supervisory relay 2? removes the short circuit from re sistance S8, and establishes a short circuit for the lamp 26. The resistance of the lamp 26 and the so that the exclusion of one from and the inclusion of the ther in the sleeve circuit, has no effect upon the relays 19 and The operation of the trunk supervi ory relay 3'? closes its contact which is in multiple with the iowercontact of relay 25.

The operator at switchboard Y may actuate listening key 39 to connect the o ators telephone set in circuit. The a ises the tion of this listening hey at sure of the middle contact thereof, whereupon marginal relay 25 releases its armatures. This is brought about by including resistance 41 in parallel with the windi g of relays 19 and :25, upon the closure of thmiddle contact of the listening lrey 39.

release of this marginal relay 2:? at this ti has no effect upon the apparatus of the trunk circuit. The reason for releasing this relay 2. 3 when the listening key 39 is actuated will more fully hereinafter appear.

llpou being advised that connection is desired with the line of subsc iber E, the operator at the switchboard restores the listening key 39 to normal cond'tion, whereupon marginal relay 25 attracts its armatures. The operator may then insert calling plug of the cord circuit D into jack to of the telephone line E, whereupn c lin supervisory lamp l? lights an d c o t off rel ay a8 operates over acircuit from battery through the lamp ll, normal rontact oi the calling supervisory relay lf), sleeve conlti. and

tacts of the plug 4.5 and the jack the winding of cutoii relay li-8 to The operation of the nects the line relay "from the 51' to connect the source of ringing current with the line for operating the usual cal bell at the station. Upon the removal oi: the receiver by subscriber in response to the operation of the call bell, sup relay 41-9 is operated to open the six about resistance 52 and to est 1 circuit for the lamp 4-? which tiuguished. versat'h, the subscribers restore v ers to the switchhoolzs, thereby can ing the appropriate supervisory lamps of the assoesistance coil So are about equal,

ciatecl cord circuits to furnish disconnect signals to the operators. The operators may thereupon Withdraw the plugs from the jacks restoring all apparatus to normal con clition.

' the operator at switchboard Y does not aituate th listening key 39, a 'ter inserting the plug into the eel: es, the answering operaters telephone set will not be connected in ci iit Wl en he originating oper- 's connected in circuit by the actuion of the listening key 6. it will be necessary, therefore, for the originating operator to rering or resignal the answering 5 operator This may be done by witliclrawing the plug 7 rroni and reinserting i into the l The uuthdrawai of the plug T jac i 8.

:"rom the jacl-c 8 causes the restoration of all the aoparatus the cert circ it, and the ct cutofi relay l5 and supervisory relay of the trunk circuit. Relay 29, in

using its armature, opens the short cireuit about the winding of relay 36, which weupon operates over a circuit from batthrough the upper contact of: in nal resistance and the winning oi 2-3-8 to ground. Relay 36, in 01 er-iting,

Jens its contacts. The opening of the lit-hand contact prevents the reestablish- 30 it ot the short circuit about its Winding n snpeuisory relay 29 again operates.

of the le'tt-hancl contact ot a opens the shor circuit about the itl ereby increasingthe resistance in with the cord supervisory relay ord suiervisory relay 2. thereupon re- 5 its arinatures n the lamp to remove the short cir- 26, and to establish a resistance 38.

' "lit" to T he uruish a signal to rater Qhe reinsertion of the jack 8 causes the open i0 illt'l ll of the cord cirthe source of ringing curn'i i' hereupon trip es causing the li iich releases ingin cur- Sugervisory pen operate. he tol'iboard Y, oliiseri'ing i oi": the lamp actu- 9 to connect tle operset at in circuit. The clone niiclclle contact of this listeireleases marginal relay 25., which 'ts upper conoict causes relar l pon the nosure t of relay 86, the aiout the winding thereof is "Giff established. The closure if the L'Ulliliiflb of relay 36 short-circuits resistance winding of the trunk 65 -Z Z}:)GT,1S )F:: relay to cause the operation the rile systein comprisfrom a first e he he second sivitihi operating ishecl upon ,econil link circuit il nieans rcspo Ive linl: circuit {G the hone hange syst uit extending sece suutchboarih a link ci vuit ,1 su'itchhoarc, a signaiingxlevice at the second switchboard operated upon conneci with trunk cirsecond switch the trunk circuit i- 3 ing the chang N i -v XiHhll i iboaiwl a ll swi' e c rcrating ciruit i means responsive to the connection or second nlt circuit with. the trunk circuit ior l act in the "i circuit, e to the {LL Jenner of the LL- '1'- L iiQiIl M16 blllil ulLbillu O iesi tance rcui thereby to ll and a sig a signal contri l therefor partially established 1 nection of the second linl: circ trunk circuit, means responsive to the lisconnection of the first link cir uit with "he c trunl: circuit for completing the partially 13 ond switchboard operated upon connection of ringing current with the trunk circuit, a link circuit at the second swi chboard, a signal control relay, an operating circuit there for partially established upon the connection of the second link circuit with the trunk circuit, means resoonsive to the disconnection oi the first link circuit with the trunk circuit for completing the partially established operating circuit, an operators telephone set at the second switchboard, a listening switch for connecting the operators telephone set with the second link circuit, and means responsive to the actuation of the listening switch for causing the opening of the operating circuit.

6. A telephone exchange system comprising trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard a source of ringing current, means in the link circuit responsive to the connection thereof with the trunk circuit for connecting therewith th source of ringing current, a signaling device at the second switchboard operating upon connection of the ringing current with the trunk circuit, a link circuit at the second switchboard, a relay in the trunk circuit, a low re sis-tance circuit connected in shunt of the relay, an operating circuit for the relay, a relay energized upon connection of the second link circuit with the trunk circuit for closing a contact in the operating circuit, means responsive to the disconnection of the first link circuit from the trunk circuit for opening the shunt circuit, thereby to cause the operation 01" the first relay, a signaling device in the second link circuit operating upon the operation of the first-mentioned relay, an operators telephone set at the second switchboard, a listening switch for con necting the operators telephone set with the second link circuit, and a shunt circuit for the second-mentioned relay established by the operation of the listening switch for causing the release of the second-mentioned relay, thereby to open the operating circuit of the first-mentioned relay.

7. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard, a source of ringing current, means in the link circuit responsive to the connection thereof with t 1e trunk circuit for connecting therewith the source of ringin current, a signaling device at the second switchboard operating upon the connection of the ringing current with the trunk circuit, a link circuit at the second switchboard, a signal control relay, a second relay in the trunk circuit responsive to the connection of the second link circuit therewith for causing the disconnection of ringing current from the trunk circuit, an operating circuit for the signal control relay partially establisher upon the response or" the second relay, and means responsive to the disconnection of the first link circuit from the trunk circuit for completing the partially established operating circuit.

8. A telephone exchan e system comprising trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard, a source of ringing current, means in the link circuit responsive to the connection thereof with the trunk cir cuit for connecting therewith the source of ringing current, a signaling device at the second switchboard operating upon the con nection of the ringing current with the trunk circuit, a link circuit at the second switchboard, a relay in the trunk circ iit responsive to the connection of the second link circuit therewith for causing the discomiection of the ringing current from the trunk circuit, a second relay, an operating circuit therefor partially established upon the response of the first relay, and a relay responsive to the disconnection of the first link circuit from the trunk circuit for completing the partially established operating circuit of the second relay, and'a signaling device in the connected second link circuit controlled by the second relay.

9. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, link circuit the first switchboard connected with the trunk circuit, a signal control relay in the trunk circuit, a link circuit at the second switchboard, an operating circuit for the signal control relay partially established upon the connection of the second link cir cuit with the trunk circuit, means respon sive to the disconnection of the first link circuit trom the trunk circuit for completing the partially established operating circuit.

10. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard connected with the trunk circuit, a signal control relay in the trunk circuit, a link circuit at the second switchboard, a second relay in the trunk circuit re sponsive to the connection of the second link circuit with the trunk circuit, an operating circuit for the signal control relay partially established upon the response of the second lOO relay, and a third relay responsive to the disconnection of the first link circuit from the trunk circuit for completing the partially established operating circuit of the signal control relay.

11. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard connected with the trunk circuit, a signal control relay in the trunk circuit, a link circuit at the second switchboard, a low resistance circuit normally connected in shunt of the signal control relay, an operating circuit for the signal control relay, a second relay in the trunk circuit responsive to the connection of the second link circuit therewith for closing a contact in the operating circuit, and a relay responsive to the disconnection of the first link cir cuit from the trunk circuit for opening the normally closed low resistance circuit, thereby causing the operation of the signal control relay,

12. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard connected with the trunk circuit, a signal control relay in the trunk circuit, a link circuit at the second switchboard, a low resistance circuit normally connected in shunt of the signal control relay, an operating circuit for the signal control relay, a second relay in the trunk circuit responsive to the connection of the second link circuit therewith for closin a contact in the operating circuit, a relay responsive to the disconnection of the first link circuit "from the trunk circuit for opening the normally closed low resistance circuit, thereby causing the operating of the signal control relay, a signaling device in the connectec second link circuit operating upon the operation of the signal control relay, an operators telephone set, a listening switch controlling the connection thereof with the s cond link circuit, and means responsive to the actuation of the listening switch for rendering the operating circuit ineffective.

in witness wher of I hereunto subscribe my name this 7th day of May, A. D. 1918.

HORACE W. ULnroi-i.

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