US1551169A - Automatic telephone system - Google Patents

Description

Aug. 25, 1.925.-

W. T. POVJELL AUTOMATIC TELEPHONE SYSTEM Filed May 8, 19;?)

WWOIFUMZ ZOU INVENTOR WINFRED T POWELTL.

BY ,&

ATTORNE Patented Aug. 25, 1925.

UNITED STATES! PATENT i-oration.

WINFRED 'r. rowELnoE ROCHESTER, NEW Yonnnssmnon TO (THE STROMBEE,G GARLSON TELEPHONE MANUFACTURING COMPANY, 0E noonns'i nn, NEW roan, A.

CORPORATION 033 NEW YORK.

AU'IQMATIC TELEPHONE SYSTEM.

Application filed May 3,

To all whom it may concern:

,Be itknown that I, \Vmrnnn T. Pow LL, a citizen of the United States, residing in Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements inAutomatic ,"lelephoneSystems, of which the ;fol lowing is a full, clear, concise, and exact description.

This invention relates to telephone systems, and more particularly to that class of telephone systems which employs automatic switches in completing a connection between a calling anda called party.

The present, invention has for its purpose the design of improved and simplified cir cuits for operating a distributor switclrand for the CQ'OPBI'ZLtlOH of this switch with other automatic switches. Other features not specifically enumerated will appear from the detailed description and from the appended claims.

The drawings diagrammatically represent a portion of the telephone system; only so much of this system is shown as is necessary for, a complete understanding of the present invention. At the lett of the drawing there is represented a calling substation, while within the d-otted rectangle there is represented the operating circuits of a line switch or distributor switch. At the rightof the dotted rectangle near the center; of the drawing the operating circuits of a connector switch are shown, while at the extreme right of the drawing a called sub-station is represented.

.The'linc orldistributor switch which will be reterred'to in the detailed description, comprises -a flat rotary switch in -which there are live series of contacts arranged to form an arcuate bank. Five brushes are provided; each one of these brushes cooperating with one of the five series of contacts. These brushes are rotated only in one direction; that is, the brushes of the switchare advanced to select anidle trunk leading to a selector or connector switch and when the connection is d-ises-tablished the brushes continue to rotate in the same directionuntil the normal position of the switch is reached.

The connector switch which will be referred to in the.description,.may;be oiithe type sul'astanti'a-lly the same as that shown 1919. ,ScriaLNo. 295,7d2.

in the patent to Keith et al. 815,176,,issuedi March 13,1906.

ltis believedithat the operation of this system will'sbestobe UDClQlShOOCLby v:descriloing the method of completing apcall from,

ers line, upper armature. andqback contact of the cut-oifrelay C0,.through the,resist anceil ,to ground.

It should be noted that the linearelay is of the differential type, that is ,,it is',d.e signed to attract its armature when either of its windings are energized, but name-.1-

diately-retracts its arn iatures whenboth of its windings are simultaneously-energized.

Since the opposing'right hand winding of thelinel relay LRisnot energized at this time, whilethe left hand windingis operated, this relay attracts. its, armatureto complete a circuit from ground through the,

lower back contact, and armature of the cut-- off relay CO, through ,the back contact,

armature and winding ofthe stepping or motor magnet MM, to groundedbattery.

Underthe control of this circuit, the motor magnet advances the five brushesrof the switch from their normal position.

It will be understood that as soon as the brushes have been HI'OVBCliflOlil normal position, that is, whenbrush5-encounters one of the, contacts 10 whiclrare connectedto groundafter the manner of an off normal, switch, the right hand windlng of the drftest brusl1-6,,tln'ough the testterininals 1-1 of busytrunks to ground at the armatures and front contacts of line relays associated with line switches that have seized these trunks; Then, however, an idle trunk found, the cutoff relayCO, isencrgized in relay at its left hand contact and armature series with the motor magnet MM, through brush 4, through terminal 9, normally closed contact 13, to ground. The motor magnet MM, however, will not operate in series with the cut-off relay. As soon as the cutoff relay G0. has operated to interrupt the circuit including the left hand winding of the line relay LR, the circuit including the right hand winding of this last named relay is effective to cause the attraction of its armature to apply a guarding potential to the selected trunk.

As soon as the idle trunk is seized, the stepping relay 'SR of the selector or connector, as the case may be, is energized over a circuit traceable from grounded battery,

winding of this relay, terminal 8, brush 3,

inner front contact and armature of the cutoff relay, through the calling subscribers sub-station circuit, upper armature and front contact of the cut-off relay, brush 2, terminal 7 of the selected trunk, winding of impedance coil 14, to ground. The stepping relay SR attracts its armature and at its front contact completes an energizing circuit for the slow releasing relay15. This completes a holding circuit for the cutoff relay CO. V

' The subscriber at A now operates his dial switch in accordance with tl e first digit of the desired number and since it has been deemed necessary to show only a connector switch, this first digit will be of the tens order. In response to the interruptions in circuit of the stepping relay corresponding to the tens digit of the wanted number, the armature of the stepping relay SR will be caused to vibrate and at its back contact, completes a circuit for the primary stepping magnet PM from grounded battery, through the winding of the magnet, side switch wiper 16 in its first position, wind-- ing of the second slow releasing relay 17, right hand front contact and armature of relay 15, back contact and armature of stepping relay SR to ground.

In response to each interruption of the line circuit, the primary magnet attracts its armature and advances its wipers one step in the primary direction. VVllen the ener' gizing circuit of the primary magnet PM was first completed, the relay 17 was energized and since this relay is slow to releaseit does not retract its armature during momentary inter "uptions of its energizing circuit. As soon as the relay 17 is energized, a circuit for the escape magnet ESC is closed and maintained, from grounded battery, resistance, winding of the escape magnet, conductor 18, make-before-break contact spring and armature of the relay 17 to ground.

the energizing circuit of the stepping relay SR will be maintained energized for a relatively long interval, so that the series circuit of the primary stepping magnet PM and the slow releasing magnet 17 is held open at the back contact and armature of the stepping relay SE. The slow releasing relay 17 under these conditions, deenergizes and thereby interrupts the energizing circuit of the escape magnet. This escape magnet, as is well known, operates on dccnergization to move the side switch wipers into their second position. The circuits of the connector are now in condition to receive the units series of impulses. In response to this series of impulses, the stepping relay SR again vibrates its armature, but in this instance controls the secondary stepping magnet SM- over a circuit completed from grounded battery, winding of the magnet SM, lower armature and back contact of the test relay 19, side switch wiper 16 in its second position, winding of the slow releasing relay 17, right hand front contact and armature of relay 15, back contact and armature of relay SR- to ground.

As soon as the relay 17 attracted its armature in response to the first of the units series of impulses, theescape magnet ESC is again energized over a circuit completed from grounded battery, resistance, winding of the escape magnet ESQ, conductor 18, makebefore-break contact spring and armature of relay 17 to ground.

When the slow releasing relay 17 deenergizes at the close of the units series of impulses, the energizing circuit of the escape magnet ESC is interrupted, if the desired line is idle, and the side switch wipers are then moved into their third position.

In thisposition or" the side switch wipers ringing current is transmitted to the called sub-station over a circuit traceable from grounded battery, through the resistance, ringing machine 23, ringing interrupter 45, the lamp 2%, winding of the slow releasing relay 25, side switch wiper 26, brush 27, through the called subscribers circuitincluding the call bell, brush 28, side switch wiper 29 in its third position, to ground. The slow releasing relay 25, which is commonly known as the ringing trip relay, is marginal and does not operate until the receiver at the called sub-station is removed from its switchhook, whereupon it receives suliicient current to operate.

As soon as the side switch moved into its third position, the escape magnet ESC was energized over a circuit extended from grounded battery, through the resistance, winding of this magnet, side switch wiper 30 in its third position, back contact and armature of release magnet REL, to ground.

The escape magnet is held energized in this At the close of the tens series of impulses,

circuit until the ringing trip relay 25 is energized on the called partys response. At

that time the escape magnet is short circnited at-thefront contact and armature of the relay 25, causing theesca-pe magnet to deenergize and move its side switch wipers into their fourth, .or talking position.

The subestations .A and YB arenow in telephonic connection, the talking battery for the calling sub-station being supplied through thewinding of stepping relay SR and impedance coil 141-, andthetalkin-g current for the called subscriber is supplied through the windings of the impedance coil 31.

It was assumed in the foregoing description that the called sub-station was unengaged. If at the timewhen the connector switch had moved its brushes 22, 27 and 28 into engagement with the terminals of the called linethis linewas busy, abusy tone would have been applied to the calling line and the connection would have failed of completion. It will be remembered that during the units series of impulses, the escape magnet ESC was energized over a circuit closed from grounded battery, through the resist ance, winding of this magnet, conductor 18, spring contact of the relay 17, to ground. At the close of this series of impulses when the relay 17 retracts its armature, a. substitute circuit for the escape magnet is completed which now extends from conductor 18,

spring and contact 20, winding of test relay 19, spring and contact of this relay, side switch wiper 21 in itssecondposit-ion, test brush 22, through the terminals of the busy line to ground at side switch wiper 21 in their third or fourth positions ,at: busy connect-ors. The test relay 19 is energized in this circuit and attracts its armature-s, and at its upper armature closes a locking circuit for itself to ground at contact 32, and off normal spring. At the uppermost armature of the test relay 1.9, a circuit is completed for applying a busytone to the callin'g line from the busy machine indicated atBZ.

At the close of theconversation when the callling subscriberreplaces his receiver on its switchhook, the stepping relay SR which :has'been maintained energized during the conversation, retracts its armature too-lose an energizing circuit for the release magnet REL, from grounded battery, winding of this. magnet, spring and off normal contact 33, right hand back contacts and armatures of relays 15 and SE, to ground. The re lease magnet is energized and operates in the well known manner to restore the connector switch to its normal position. It will be seen that as soon as the relay 15 deenergizes, that the holding circuit of the cutofl. relay CO is broken at the left hand front contact and armature of the relay 15. As soon as the cut-off relay deenergizes, the motor magnet MM is operated over a circuit extending frOlIl grounded batter" ,winding, arm atnre and back contact of the motor magnet MM, lowerarmature and back contact of the cut-,oifrelay, front contact and armature of line relay-LR, to. grounded battery. The line switch continues to advance its brushes in the same direction in which it moved to select. an idle trunk untilthe brush 5 engages the normal contact 13, whereupon the line. relay LR retracts its armature to interrupt the operating circuit of the motor magnet. in condition to receive another call.

In the present disclosure the circuits of the invention have been shown associated with a line switch which operates to select idle trunks leading to connector switches, but it will be understood that. these circuitsmay be employed with any distributor switch,

and if utilized as a line switch, maybe. em-.

ployed to select idle trunks leading toxselec tor switches instead of to connector switches as herein disclosech. It will be readily understood that the distributor circuits here disclosed may be employed to apportion calls .1

to operators on a call distributing system. lVhat I claim is: 1. In a telephone system, ,anincioming line, a. plurality of. out-going lines, a differential line relay individual to each incomingline.

and controlled in part thereover, a-"cutofi relay individual to each incoming line, a switch for connecting said incoming line to any outgoing line, an operating.magnetior said switch, and a circuit for saidimagnet The apparatus is now jointly controlled by said line andcut-oii relays.

2. In a telephone system, an incom ng l ne,

outgoing lines, a switch for interconnecting said incoming line with any of said outgoing lines, said switch having a normal position, controlling means for said switch including a line relay initially energized over said incoming line, n'ieans for 'deenergizing said line relay as soon as theswitch ismoved from its normal position, a cut-cit relay operative when-an outgoing line is seized, a magnet for advancing said switch, and a circuit for said magnet jointly controlled by said line and cut-oft relays.

Inan automatic telephone system, an incoming circuit, a plurality of outgoing circuits, a switch for interconnecting said incoming circuit with any of said outgoing circuits,a cut-off relay'individual to said incoming circuit, a line relay having contacts cooperating in the control of said switch, a circuit for said line relay normally connects ing it to said incoming circuitthrough con.- tacts of said cut-.oiii' relay, means for energizing said line relay and said cut-cit relay when said switch seizes an outgoing circuit, and a busy potential for said selected outgoing circuit applied at contacts of said line relay.

Jil

' 4. In a telephone system, an incoming line,

a plurality of outgoing lines, a normaling non-numerical switch for interconnecting said incoming line with any of said outgoing lines, a line relay cooperating in the control of said switch, means-to energize said line relay, means responsive to the energization interconnecting said incoming line with any,

of said outgoing lines, a line relay cooperating in the control of said switch, and means controlling said line relay for energizing the same to initiate the operation of said switch, for deenergizing the same during the outgoing line selection operation of said switch and for energizing the same again during the holding of said outgoing line and during the release movement of said switch.

6. In a telephone system, an incoming line, a plurality of outgoing lines, a switch for interconnecting said incoming line with any of said outgoing lines, a line relay and a cut-oil relay cooperating in the control of said switch, means for energizing said line relay to initiate the line selectin operation of said switch, for deenergizing said line relay during the line selecting operation of the switch, means for operating said cutoff relay when an outgoing line is seized, and means including a portion of said first mentioned means and controlled in part by said cut-off relay for energizing said. line relay to effect the release of said switch.

7. In a telephone system, an incoming line, a plurality of outgoing lines, a switch for interconnecting said incoming line with any 01 said outgoing lines, a line relayand a cut-off relay individual to each line, a motor magnet for advancing said switch, said line relay having windings diilerentially arranged, a circuit for one winding of said line relay completed over said incoming line, a cir cuit for the other winding of said linerelay completed as soon as said switch is advanced, operating circuits for said motor magnet controlled in part by said line and cut-oft relays, and a circuit for said cut-ofi relay in shunt oi the operating circuits of said motormagnet completed while busy trunks are being tested.

8. In a telephone system, an incoming line, a plurality of outgoing lines, a switch for interconnecting said incoming line with any 01 said outgoing lines, a. motor magnet for advancing said switch, a line relay cooperating in the control of said motor magnet, said line relay having two windings, a circuit completed through one of the windings of said line relay to cause said motor magnet to advance said switch, means to cause said motor magnet to continue the advance of said switch, and a circuit completed through the other winding of said line relay until said switch is in its normal position for caus- .ing said motor magnet to restore said switch to normal, position. i

9. In a telephonesystem, a plurality of points, means for making points unselectable, a non-numerical point finder, a relay having one winding for initiating the movement of said point finder, means for continuing the movement of said point finder, a second'winding on said relay for causing an additional movement of said point finder, means for stopping the point finder in engagement with a selectable point, means including a circuit through one winding of said relay to energize the same and means to complete a circuit through another winding of said relay to deenergize the same.

10. In a telephone system, an incoming line, a plurality of outgoing lines, a switch for interconnecting said incoming line with any of said outgoing lines, an oil-normal contact on said switch, a difi'erential line relay individual to eaclrincoming line and cooperating in the control of said switch, said relay having two windings, one winding of said relay being energized over the incoming line to start said switch, a circuit for the other winding of said relay completed through said oil-normal contacts, means for advancing the said switch, and a circuit for said means controlled in part at said line relay.

11. In a telephone system, an incoming telephone line, aplurality of outgoing trunks, means for characterizing said trunks by a busy or idle condition, av switch for interconnecting said incoming telephone line with any idle trunk, a dillerential line relay arranged to be energized over two sides of the talking conductors of said telephone line in series, means for deenergizing said line relay while busy trunks are being en countered and for energizing said line relay when an idle trunk is seized, means for advancing said switch, and an operating circuit for said means completed by said line relay.

In witness whereof, I hereunto subscribe my name this 7th day of May A. D. 1919. VVINFRED T. POWELL.

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