US1337714A - Automatic telephone-exchange system - Google Patents

Description

J. L. McQUARRlE. AUTOMATIQ TELEPHONE EXCHANGE SYSTEM.

APPLICKTION FILED JULY 2119!].

Patented Apr. 20, 1920.

//1ven/0/ James L. M Quark/e Q mobuzzou UNITED STATES PATENT OFFICE.

JAMES II- MOQUARRIE, 6F MONTCLAIR, IIE'W JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCGRPGRATEID, OF NEW YORK, N. 1., A CORPORATION OF NEW YORK.

AUTOMATIQ TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Apr. 20, 1920.

Application filed July 2, 1917. Serial No. 178,234.

To all whom it may concern:

Be it known that I, JAMEs L. MCQUAR- RIE, a citizen of the United States, residing at Montclair, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Automatic Telephone-Exchange Systems, of which the following is a full,iclear, concise, and exact description.

This invention relates to automatic telephone exchange systems, and more particu larly to an arrangement for controlling the operations of the selective switches employed in such systems.

It is the object of the present invention to provide means whereby a train of automatic switches may be controlled by a single auxiliary controlling switch.

A feature of the invention is the provision of an auxiliary controlling switch at the first switch of a train of selective switches, this auxiliary switch serving to control the various operations not only with the switch with which it is associated, but also of the succeeding switches with which it is successively associable.

The invention has been shpwn applied to a system of the well-known step-by-step full automatic type, but it is to be understood that the invention is not to be restricted to any particular system, since the inventive idea may be applied to a large variety of systems.

Referring now to the drawing, there is illustrated a circuit arrangement suitable for operating a train of automatic switches in accordance with the features of the present invention.

The structure of the auxiliary circuit con trolling switch has not been disclosed, the arrangement including merely a plurality of wipers mounted on a common shaft and arranged to be successively advanced into stopping positions under the control of an escapement magnet, upon each deenergization of such controlling escapement magnet. Since switches of this general type are well known, it has not been'considered necessary to specifically disclose the structure of this switch. The switch is arranged to be mechanically restored to normal when the first selector switch returns to its normal position.

The selective switches whose operating circuits are shown, may be in general any well-known type of step-by-step switch arranged for motion in two directions under the control of primary and secondary stepping magnets.

It is thought that the invention will best be understood by describing the operation of the circuits as utilized in setting up a call between a calling and a called subscriber.

If the subscriber whose substation is indicated at A desires a connection with a subscriber whose substation is indicated at B, he will remove his receiver from the hook, whereupon his line will be extended to the first selector shown in the drawing in any well-known manner, it being assumed in the present case that a line finder, whose brushes are indicated at l and 2, is utilized for this purpose.

As soon as the calling line is extended to the first selector, line relay 3 is energized by means of a circuit extending from grounded battery, right-hand winding of relay 3, finder brush 2 and its associated contact, the loop of the calling subscribers line finder brush 1 and its associated contact, lefthand winding of the line 3, to ground. The resultant energization of line relay 3 com pletes a circuit from grounded battery,

'inding of slow-release relay l, armature and front contact of relay 3 to ground. lVhen the subscriber operates his sending device indicated at 5 to transmit the first series of impulses, line relay 3 will be intermittently de'e'nergized in response to such impulses. Upon the first denergization of line relay 3 a circuit is closed from grounded battery, winding of slow-release relay 5, right-hand armature and front contact of relay 4, which being slow to release, maintains its armatures during the sending of impulses, armature and back contact of relay to ground. At the same time a parallel circuit is completed from grounded battery the primary stepping magnet 6 of the first selector, side-switch wiper 7 in its first position, right-hand armature and front contact of relay 4, armature and back contact of relay 3, to ground. Magnet 6 is energized in this circuit and moves the first selector brush shaft one step in a primary or group selecting direction. The energization of relay 5 completed a circuit from grounded battery, winding of escape magnet 8, side-switch wiper 9 in its first po sition, conductor 10, right-hand armature and front contact of relay 5, to ground. The escape magnet is energized but does not release the side switch. Relay 5 being slow to release retains its armatures during the sending of the first set of impulses in response to which the stepping magnet 6 is intermittently energized to advance the brush set into operative relation with the group of trunks leading to a second selector serving connectors through which the desired line maybe reached.

Upon the completion of the first series of impulses, line relay 3 remains energized for a comparatively long interval, and relay is deenergized, causing in turn the denergization of escape magnet 8, which upon deenergization releases the side switch into its second position. In the second position of the side switch, a circuit is completed for escape magnet 8 from grounded battery, winding of magnet 8, side-switch wiper 9 in its second position, conductor 11, sideswitch wiper 12 in its second position, and secondary off-normal contact 13, to ground. At the same time a circuit is completed from grounded battery, winding of secondary stepping magnet 14, its armature and back contact, conductor 15, side-switch wiper 16 in its second position, armature and front contact of line relay 3, to ground. Stepping magnet 14 interrupts itsown circuit to advance the brush set over the trunk terminals in the selected grpup until an idle trunk is found. If we assume that busy trunks are characterized by the presence of ground on their test contacts 17, escape magnet 8 will remain energized until an idle trunk is found, since although the path to ground by way of off-normal contact 13, which is opened as soon as the switch makes its first secondary step, is broken, an alternate holding path will be found by way of conductor 18, test brush 19 and test terminal 17, to ground. As soon as test brush 19 encounters a contact corresponding to 17 which is free from ground, escape magnet 8 will be deenergized and will release the side switch into position three, opening the circuit of stepping magnet 14 and bringing the brush set to rest on the terminals of an idle trunk. When the side switch moves into position three, ground is supplied to test terminal 17 from ground, side-switch wiper 12 in its third position, conductor 18 and brush 19, to render this line non-selectable to other hunting selectors. This protecting ground is maintained on terminal 17 through the successive positions of the side switch, and maintains the trunk busy until the side switch has been restored to its normal position.

The calling subscriber now operates his sender 5 to transmit a second series of impulses. As before, the first deenergization of relay 3 completes a circuit for slow-release relay 5, causing in turn the energization of escape magnet 8 over a circuit traceable from grounded battery, winding of magnet 8, side-switchwiper 9 in its third position, conductor 10, right-hand armature and front contact of relay 5, to ground. Primary steppingmagnet 20 at the second selector is intermittently energized in response to the vibration of the armature of line relay 3 over a circuit extending from grounded battery, winding of stepping magnet 20, contact 21, brush 22, conductor 23, side-switch wiper 7 in its third position, right-hand armature and front contact of slow-release relay 4, armature and back contact of relay 3, to ground. Upon the termination of the second series of impulses, relay 3 remains energized for a relatively long period of time, causing as before the deenergization of relay 5. When relay 5 deenergizes, escape magnet 8 is deenergized in turn, allowing the side switch to be released into its fourth position.

In the fourth position of the side switch, escape magnet 8 is energized over a circuit from grounded battery, side-switch wiper 9 in its fourth position, conductor 24, sideswitch wiper 25 in its fourth position, conductor 26, brush 27, contact 28, conductor 29, to ground by way of secondary off-normal contact 30. At the same time a circuit is completed for the secondary stepping magnet 89 of the second selector from grounded battery, armature and back contact of magnet 89, contact 31, brush 32, sideswitch wiper 16 in its fourth position, armature and front contact of relay 3, to ground. Stepping magnet 89 interrupts its own circuit and causes the second selector brush set to be advanced over a selected group of trunks in search of an idle trunk line therein. As soon as the second selector moves away from its normal secondary position, off-normal contact 30 is opened, but an alternate holding circuit for escape magnet 8 is found as long as test brush 33 encounters the test contacts of busy lines, which are characterized, as in the case of the first selector, by the presence of ground potential on their test contacts. This circuit extends from grounded battery, winding of magnet 8, side-switch wiper 9 in its fourth position, conductor 24, side-switch wiper 25 in its fourth position, conductor 26, brush 27, contact 28, brush 33, test contact 34, to ground. As soon as brush 33 encounters a contact 34 associated with an idle trunk line, the absence of ground allows the escape magnet 8 to denergize, moving the side-switch wipers from position 4 to position 5 and therefore opening at wiper 16 the previously traced circuit for stepping magnet 89. The brush set is therefore brought to rest on the terminals of the trunk leading to an idle connector switch serving lines including that of the desired subscriber. lVhen the side switch is moved into its fifth position, ground is supplied to test contact 34 from ground, side-switch wiper 25 is in its fifth position, conductor 26, brush 27, contact 28 and test brush 33, in order to render this line non-selectable to other hunting selectors. This ground is maintained throughout the succeeding positions of the side switch.

The calling subscriber now sends a third series of impulses to operate the seized connector switch in its primary movement. Upon the first deenergization of relay 3, slowrelease relay 5 is energized as before, causing in turn the energization of escape magnet 8. At the same time a circuit is completed from grounded battery, winding of primary stepping magnet 35 of the connector, contact 36, brush 37, contact 38, brush 39, conductor 40, side-switch wiper 7 in its fifth position, right-hand armature and front contact of relay 4, armature and back contact of relay 3, to ground. Stepping magnet 35 is intermittently energized in response to the vibration of the armature of line relay 3, to advance a connector brush set into operative relation with a desired group. Upon the completion of the series of impulses, line relay 3 is maintained energized for a relatively long interval and slow-release relay 5 dee'nergizes, causing in turn the cleenergization of escape magnet 8, which by deenergizing moves the side switch out of its fifth and into its sixth position.

When the calling subscriber sends the final series of impulses, slow-release relay 5 is energized to control escape magnet 8 as before described. In this case, secondary stepping magnet 41 of the connector is operated in response to the operation of line relay 3 over a circuit from grounded battery, winding of stepping magnet 41, contact 42, brush 43, contact 44, brush 45, conductor 46, side-switch wiper 7 in its sixth position, right-hand armature and front contact of relay 4, armature and back contact ofv relay 3, to ground. Upon the termination of this series of impulses, relay 5 is rle'energized, and if the desired line is idle, as will be assumed in the present case, escape magnet 8 will be deenergized to allow the side switch to be released into its seventh position.

In position 7 of the side switch, a circuit is completed from grounded battery, winding of escape magnet 8, side-switch wiper 9 in its seventh position, conductor 47, armature and back contact of ringing cut-off relay 48, to ground. A circuit is then completed from ground, ringing generator 49, winding of relay 48, armature and front contact of escape magnet 8, conductor 50,

sideswitch wiper 51 in its seventh position, brush 52, contact 53, brush 54, contact 55, brush 56, contact 57, the loop of the called subscribers line, contact 58, brush 59, contact 60, brush 61, contact 62, brush 63, sideswitch wiper 64 in its seventh position, to ground. lVhen the called subscriber responds by removing his receiver from the switchhook, the resistance of this circuit will be sufliciently lowered to allow relay 48 to energize, thereby opening the circuit of escape magnet 8 and allowing this magnet to deenergize and release the side switch into its eighth position. In the eighth position of the side switch, talking circuit is completed to the called subscriber by way of wipers 51 and 64, battery being supplied to the called line through the windings of a feed coil 65.

As soon as the side switch moved into its seventh position, guarding potential is sup plied to the test contact 66 of the called line from ground, side-switch wiper 67 in its seventh position, conductor 68, brush 69, contact 70, brush 71, contact 7 2, and brush 73, to render this line busy to other con-- nectors. This ground is also maintained in the final position of the side switch.

If the desired line had been busy, escape magnet 8 would not have been deenergized upon the completion of the final series of impulses, since a holding circuit would exist, from grounded battery, winding of escape magnet 8, conductor 74, side-switch wiper 67 and its sixth contact, conductor 68, brush 69, terminal 70, brush 71, contact 72, brush 73, and multiple contact 66 to ground. Escape magnet 8 would therefore not release the side switch into its seventh position.

In parallel with the above traced circuit, a circuit would be completed from grounded battery, left-hand armature and back contact of relay 5, winding of busy relay 75, conductor 74, to ground over the path described. Relay 75, upon energization, locks up through its left-hand armature and front contact to ground at the left-hand armature and front contact of relay 4. At the same time an induced alternating current is supplied to the windings of coil 65 over a path from ground,-busy tone apparatus 7 6,-righthand armature and front contact of relay 7 5, to ground through the right-hand winding of coil 65. The inductive action of this current on the windings of coil 65 causes alternating current to be transmitted through the condensers 77 and 78 to the calling subscribers substation, and will produce a characteristic tone in his receiver to inform him that the desired line is busy. He will thereupon replace his receiver upon the hook and cause the release of the switches in a manner now to be described.

When the calling subscriber replaces his receiver, relay 3 is decnergized and causes after a short interval, the deenergization of slow-release relay 4. Parallel circuits are then completed for release magnets 7 9, 80 and 81 respectively, by way of the righthand armatures and back contacts of relays 4 and 3. The circuit of release magnet 81 extends from grounded battery, winding of release magnet 81, off-normal contact 82, terminal 83, brush 84, contact 85, brush 86, oilnormal contact 87, right-hand armature and back contact of relay 4, armature and back contact of relay 3, to ground. The circuit of release ma et 80 extends from grounded battery, winding of release magnet 80, offnormal contact 88, contact 85, brush 86, to ground over the path described. The circuit of releasev magnet 79 extends from grounded battery by way of off-normal contact 87, to ground, as described. In each case the release magnet attracts its armature and locks itself to ground until the switch is fully restored, at which time the associated off -normal contact will be opened. The restoration of the first selector causes the restoration of the controlling side switch. The line finder switch whose brushes are indicated at l and 2, may be restored in any well-known manner in accordance withthe type of finder used.

It is to be observed that the release of the switches will be accomplished in the same manner regardless of the point of operation at which the calling subscriber desires to release the connection, since at any time that relays 8 and 4 deenergize, release circuits will be completed for the magnets of any switches which have been operated.

What is claimed is:

1. In a telephone exchange system, calling and called subscribers lines, a plurality of switch devices for interconnecting a calling and a called line, a test circuit for each of said switch devices, and a test relay common to said test circuits.

2. In a telephone exchange system, calling and called subscribers lines, a plurality of switch devices for interconnectin a calling and a called line, a test circuit Ior each of said switch devices, and a test relay located at one of said switch devices and common to said test circuits.

3. In a telephone exchange system, calling and called subscribers lines, a train of switch devices for interconnecting a calling and a called line, a test circuit for each of said switch devices, and a test relay associated with the first switch of the train and common to said test circuits.

4. In a telephone exchange system, calling and called subscribers lines, a first selector,

a second selector, a connector switch for interconnecting said lines, a test circuit for each of said switch devices, and a test relay associated with the first selector and common to said test circuits.

5. In a telephone exchange system, calling and called subscribers lines, a train of switch devices for interconnecting a calling and a called line, a test circuit for each of said switch devices, and an auxiliary switch and test relay common to said test circuits.

6. In a telephone exchange system, calling and called subscribers lines, a train of switch devices for interconnecting a calling and a called line, a test circuit for each of said switch devices, and an auxiliary switch common to said test circuits.

7. In a telephone exchange system, calling and called subscribers lines, a train of switch devices for interconnecting a calling and a called line, a test circuit for each of said switch devices, an auxiliary switch located at the first switch device of the train, and a test relay, said test relay and auxiliary switch being common to said test circuits.

8. In a telephone exchange system, calling and called subscribers lines, a train of switch devices for interconnecting a calling and a called line, a test circuit for each of said switch devices, a single test relay, and means for successively associating said test relay with the test circuits of the switch devices.

9. In a telephone exchange system, calling and called subscribers lines, a train of switch devices for interconnecting a calling and a called line, a stepping relay associated with the first switch of said train, a test circuit for each of said switch devices, a test relay common to said test circuits, a release magnet associated with each switch device, and release circuits for said switch devices independent of said test circuits, all including the armature of said stepping relay.

10. In a telephone exchange system, calling and called subscribers lines, a train of switch devices for interconnecting a calling and a called line, including a stepping magnet associated with the first device of said train, a test circuit for each of said switch devices, a test relay common to said test circuits, a release magnet associated with each switch device, and release circuits for said switch devices independent of said test circuits, all including the armature of the stepping magnet associated with the first switch device of the train.

In witness whereof I hereunto subscribe my name this 29th day of June, A. D. 1917.

JAMES L. MOQUARRIE.

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