US1245748A - Telephone-exchange system. - Google Patents

Description

A. E. LUNDELL.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JULY 5,1916.

Patented Nov. 6, 1917.

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UNITED STATES PATEN '11 FFEQEQ ALBEN E. LUNDELL, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY INCORPORATED, OF NEW YORK, N. 1., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed July 5, 1916.

To all whom it may concern:

Be it known that 1, Annex E. LUNDELL, a citizen of the United States, residing at New York, in the county of Bronx and and State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description. 7

This invention relates to telephone eX-. change systems, and more particularly to systems in which machine switching is employed.

An object of this invention is to provide simple testing means for the switches at the ends of a double switch-ended trunk.

An additional object of the invention is to provide simple testing means for hunting switches in a system in which means are provided for indicating to an operator the class of service to which a calling subscriber is entitled.

In a well-known type of class of service indicating device, a high voltage battery is used, its purpose being to intermittently send impulses to operate an indicating device. If a hunting finder should be passing over the terminals of a line at the instant an impulse is being sent by the class of serrice indicating device of such line, the test relay of the finder would be energized and the finder would stop on the terminals of a non-calling line, unless means are pro vided to prevent such action.

A feature of the invention is the use of a single test relay to control both the line finder switch and the cord selector switch of a connecting cord circuit.

A further feature of the invention is a relay having a double winding, themagnet-ic effect of these windings being differential when the brush set of a finder is passing the terminals of a non-calling line at the instant an impulse is being sent by the class of service indicating device of such line.

A still further feature of the invention is the provision of a centering brush which is in electrical connection with a commutator segment at the time the brushes are centered on a terminal set,-the circuit of such centering brush being through one winding of a test relay.

In the embodiment shown the finder switches, cord selector switches and con- Specification of Letters Patent.

Serial No. 107,551.

trolling sequence switches may be of the type disclosed in Patent No. 1,168,319, issued January 18, 1916 to Alben E. Lundell.

It is thought that the invention will best be understood from the following detailed description, reference being had to the accompanying drawing.

In the drawing, the portion to the left of the dotted line indicates schematically the substation apparatus of a calling subscriber and a connecting cord circuit including a line finder switch anda cord selector switch. The portion ofthe drawing to the right of the dotted line indicates an operators cord circuit and the substation apparatus of a called subscriber. 7

When the subscriber at substation S desires a connection, he removes his receiver from the hook, whereupon line relay 1 is energized in the-well-known manner and closes a circuit for relay 2 from grounded battery A, contact 3, lamp 8, armature and front contact of relay 1, and the winding of relay 2, to ground, provided that conta' t 3 is closed at this time. If contact 3 is open, contact 6 W111 be closed as will be later described, and the circuit of relay :2 under this condition is from grounded battery B, contact 6, resistance 7, lamp 8, to ground over the path just traced. Relay 2 is energized and attracts its armature, closing a circuitv from ground, armature and front contact of relay 2, sequence switch contact 102, and the winding of power magnet 100 of the connecting cord sequence switch SS, to grounded battery A. The sequence switch SS moves from position 1 to position lunder the con-' trol of its normal contact 101. its the sequence switch SS passes through position 2 and comes to rest in position 4, a circuit is closed from grounded battery A, winding of lip-drive magnet 103, sequence switch conk tact 10%, to ground at the right-hand armature and back contact of test relay 105. Under the control of magnet 103, a brush set 106, 107, 108, 109 and a centering brush 110 are moved upward, the brush set passing over terminal sets 111, 112, 113, 114 and the centering brush passing over a commutator strip 115.

At this time it mightbe well to describe the operation of a device for transmitting impulses to a class of service indicating means at an operators position, suchdevice Patented Nov. 6, 1917.

being indicated at 4 and 5. 1 and 5 are coir stantly rotating cams operating spring contacts 3 and 6. The relation of the cams and switch springs is such that just before contact 3 is opened, contact 6 is closed. Ii we assume now that battery A is of low voltage, for instance, twenty-four volts, and battery B is of high voltage, for instance, forty-eight volts, an in pulse of high voltage will be transmitted to terminal 111 on each revolution of the shaft driving the cams 1 and 5, the circuit being from grounded battery 13, contact resistance 7, lamp 8, conductor 9, to terminal 11. By suitable arrangement and cutting of the cams 4 and 5, any desired number of impulses per revolution may be sent.

WVhen the brush set 106, 107, 108, 109 arrives on the terminals or the calling line, a circuit is closed from grounded battery, lefthand winding of relay 105, sequence switch contacts 116, 117, conductor 118, brush 106, terminal 111, conductor 9, armature and front contact of relay 1, winding of relay 2, to ground. When the brush set is centered on the terminals, a parallel circuit is closed from grounded battery A, right-hand winding of relay 105, resistance 119, sequence switch contact 120, a conducting segment of commutator 115, and brush 110, to ground. The windings of this relay are so arranged that the energy supplied through the righthand winding and the circuit just traced, is insufficient to operate the relay, but when in addition, energy is supplied to the left-hand winding through the circuit previously traced when the wiper 106 comes in contact with the terminal 111 of the calling line, it is sufficient to operate the relay 105. Relay 105 thereupon attracts its armatures, opening at its right-hand armature the previously traced circuit of the up-drive magnet 103, thus causing the brush set to come to rest on the terminals of the calling line. At its left-hand armature and front contact, relay 105 establishes a locking circuit for itself from grounded battery A, left-hand windin and left-hand armature and front contact of relay 105, sequence switch contact 121, brush 107, terminal 112, and cut-0E relay 10, to ground. Message register magnet 15 is included in the parallel branch of this circuitbut is not energized at this time since it is marginal and will not energize in series with a resistance when subjected only to current from low voltage battery A.

Cut-off relay 10 is energized in this cir cuit and remains energized until the conclusion of the conversation, its circuit being maintained while the sequence switch is moving from positions 4:3 to 10 by sequence switch contact 155 over a circuit from grounded battery A, resistance 156, sequence switch contact 155, brush 107, terminal 112, winding of relay 10, to ground. In positions 10 to 1st of the sequence switch SS, relay 10 is maintained energized in series with a relay 139, as will be described later.

It should be noted at this point that if the brush set passes the terminals oi a non-calling line at the instant a high voltage impulse is being sent by the class of service impulse transmitting device C, a circuit will be closed from high voltage battery B, contact 6, resistance 7, lamp 3, conductor 9, terminal 111, brush 100, conductor 113, sequence switch contacts 116, 117, left-hand winding of relay 105, to low voltage battery A, to ground. This current, however, flows through the left-hand winding of relay 105 in a direction such that the magnetism set up by said current opposes that set up through the right-hand winding of relay 105, by the engagement of centering brush 110 with a conducting segment of commutator strip 115. Relay 105 will, therefore, not be encrgized and the brush set will pass the tcrminals of such undesired line.

When relay 105 attracted its right-hand armature, a circuit was closed from ground, through the right-hand armature and front contact of relay 105, sequence switch contact 122, and the winding of power magnet 100 to grounded battery A. The energization of power magnet 100 moves the sequence switch from position at to position 9.

lVhen the sequence switch leaves position 4-, the circuit of the right-hand winding of relay 105 is broken at sequence switch contact 120, and when the sequence switch leaves position 13;, the locking circuit of relay 105 through its left-hand winding is broken at sequence switch contact 121. Re lay 105 is deenergized and releases its ar1natures.

sequence switch SS passes through position 8, a circuit is closed from grounded battery A, through the winding or" up-drive magnet 123, sequence switch contact 12 1, to ground at the righthand armature and back contact of relay 105. Under the control of the up-drive magnet, the brushes 125, 126, 127, 123 of a cord selector are moved upward over terminal sets 129, 130, 131, 132. A centering brush 133 is also carried upward by the brush carriage and moves over a commutator segment 13%. When the brush set arrives on the terminal set of an idle cord, as indicated by the presence of ground on the test terminal 129, a circuit is completed from grounder battery A, through the left-hand winding of relay 105, sequence switch contacts 116, 135, conductor 136, brush 125, terminal 129, and operators sequence switch contact 200, to ground. A circuit is also completed from grounded battery, through the right-hand winding of relay 105, resistance 119, sequence switch contact 137, a conducting seg ment of commutator 134-, and brush 133, to

ground. Relay 105 thereupon attracts its armatures, completing, at its right-hand armature and front contact, a circuit from ground through sequence switch contact 122 and the winding of power magnet 100, to grounded battery, for moving the sequence switch out of position 9 and into position 14. WVhen relay 105 attracted its righthand armature, it broke the circuit of the up-drive magnet 123 which deenergizes and allows the brush set to come to rest on the desired terminal set.

lVhen the cord selector CS came to rest on the terminals of an operators cord circuit, a circuit was completed from grounded battery, power magnet of sequence switch 210, contact 212, terminal 131, brush 126, relay 139, contact 138, brush 107, terminal 112, winding of cut-off relay 10 to ground, for moving the operators sequence switch 210 from position 1 to position 7, under the control of its normal contact 211.

In position 7 of the operators sequence switch SS, a circuit is closed from ground, winding of cutoff relay 10, terminal 112, brush 107, sequence switch contact 138, the winding of relay 139, brush 126, terminal 130, operators sequence switch contact 201, spring contact 202 of relay 209, and the winding of a relay 203, to grounded battery A; Relay 139 is energized and remains energized until the conclusion of the conversation. Relay 139, in energizing, completes an impulse circuit as previously described, from grounded high voltage battery B, contact 6, resistance 7, lamp 8, conductor 9, terminal 111, brush 106, conductor 118, left-hand armature and front contact of relay 139, sequence switch contacts 140, 135, conductor 136, brush 125, terminal 129, operators sequence switch contact 204, key 205, and the winding of relay 206, to grounded low voltage battery A. The higher voltage of battery B overcomes the potential of low voltage battery A, and current flows in the direction in which the circuit was traced. The impulses intermittently sent successively operate counting relays in the wellknown manner to operate a device for indicating to the operator the class of service to which the calling subscriber is entitled. The counting relays and indicating device controlled by relay 206 may be similar in construction and operation to those described in Patent No. 1,200,788, issued October 10, 1916, to S. B. \Villiams, Jr. Relay 206 has a high resistance winding and the lamp 8 is not lighted at this time. The operator by depressing key 205 may complete a circuitfrom high voltage battery B, resistance 207, key 205, operators sequence switch contact 204, terminal 129, brush 125, conductor 136, connecting cord sequence switch contacts 135 and 140, left-hand armature and front contact of relay 139, conductor 118, brush 106, terminal 111, conductor 9, lamp 8, contact 3, low voltage battery A, to ground. This circuit will be intermittently completed by the operation of contacts 3 and 6, the object of the lamp 8 being to inform the operator of the number of the calling subscriber, if for any reason she wishes to checkthis information.

The operator then extends the connection to the wanted subscriber by means of a con-- nector switch whose brushes are indicated at 300 and 301, the connector being of any wellknown type.

When the called subscriber answers, the operator is informed of his answering by means of a well-known supervisory signal (not shown) and depresses a key208 to con trol the message register device operated by the magnet 15. When the key 208 is depressed, acircuit is closed for a relay 209 from grounded battery, winding of relay 209, and key 208 to ground. Relay 209, in attracting its armature, connects battery directly to terminal 131'instead of through the resistance of the winding of relay 203. The increased current flow allows the marginal relay 1.5 controlling the message register device to operate and the call is recorded.

At the completion of conversation, the operator is informed by the operation of wellknown supervisory signals that both subscribers have replaced their receivers. The operator then depresses key 215 to complete a circuit from grounded battery, power magnet of sequence switch 210, contact 216, closed contacts of key 215 to ground, for moving the oper ators sequence switch out of position 7. Then the operators sequence switch leaves position 7, the holding circuit of relay 139 is broken and relay 139 is cleenergized. Relay 139 in falling off completes a circuit from ground, right-hand armature and back contact of relay 139, connecting cord sequence switch contact 141, and the winding of power magnet 100 to battery, for moving the connecting cord sequence switch SS out of position 14 and into position 15. In position 15 a circuit is com pleted from grounded battery, through the winding of down-drive magnet 142, conductor 143 and sequence switch contact 144, to ground. Under the control of magnet 142 the line finder brush carriage is moved downward. On arrivingin its normal position, a circuit is completed from ground, a brush 145, conducting segment 146, conductor 147, sequence switch contact 148 and the winding of power magnet 100, to grounded battery, for moving the connecting cord sequence switch out of position 15 and into position 16. In position 16, a circuit is completed from grounded battery, downdrive magnet 149, sequence switch contact 150, to ground. Under the control of the downdrive magnet the brush set of the cord selector CS is returned to normal. On its arrival in normal position, a circuit is completed from ground through a brush 151, a conducting segment 152, conductor 1523, sequence switch contact 15% and the winding of ower magnet 100, to grounded battery, for moving the sequence switch SS from position 18 to position 1. The connecting cord circuit is now restored to normal and is ready to receive another call.

he operators cord circuit is restored to condition for receiving a call in a wellknown manner which it has not been con sidered necessary to describe.

\Vhat is claimed is:

1. In a telephone exchange system, the combination with a connecting circuit provided at its incoming end with a switch for establishing connection to a calling line, and at its outgoing end with a switch for extending the connection, of a single relay for controlling the hunting operation of either one or both of said switches.

2. In a telephone exchange system, the combination with a connecting circuit provided at its incoming end with a switch for establishing connection to a calling line, and at its outgoing end with a switch for extending the connection, of a single relay for controlling the hunting operation of either one or both of said switches, and means for transferring the test circuit of said relay from the first of said switches to the second of said switches.

3. In a telephone exchange system, the combination with a connecting circuit pro vided at its incoming end with a switch for establishing connection to a calling line, and at its outgoing end with a switch for extending the connection, of a device for indicating to an operator the class of service to which a calling subscriber is entitled, and a test relay common to said switches.

In a telephone exchange system, a connecting circuit provided at its incoming end with a switch for establishing connection to a calling line, and at its outgoing end with a switch for extending the connection, subscribers lines terminating in a contact bank of the first of said switches, a brush carriage for the first of said switches, a device for indicating to an operator the class of service to which the calling subscriber is entitled, a test relay common to both of said switches, and means to prevent the energization of said. relay at the time the finder brush set is passing over the terminals of a line whose class oi service indicating device is operating.

5. In a telephone exchange system, a connecting circuit provided at its incoming end with a switch for establishing connection to a calling line, and at its outgoing end with a switch for extending the connection, subscribe-rs lines terminating in a contact bank of the first of said switches, a brush carriage tor the first of said switches, a device for indicating to an operator the class of service to which the calling subscriber is entitled, a test relay common to both of said switches, and a double winding for said relay, the magnetic effect of said windings being differential to prevent the energization of said relay when a brush set passes over the terminals of a line at the instant the class of service indicating device of such line is operating.

in a telephone exchange system, a connecting circuit provided at its incoming end with a switch for establishing connection to a callin line, and at its outgoing end with a switch for extending the connection, subscribers lines terminating in a contact bank or the first of said switches, a brush carriage for the first of said switches, centering brushes for said switches, commutator segments to be traversed by said centering brushes, said centering brushes being in electrical connection with a conducting segment at the time a brush set is positioned on the terminals of a calling line, a device for in dicating to an operator the class of service to which the calling subscriber is entitled, a test relay common to both of said switches, said relay having a double winding, the circuit oi? one of said windings extending through the centering brush of whichever of said switches is operating, means for causing the magnetic effect of said windings to be differential when the brush set is passing the terminals of an undesired line, and means for causing the magnetic effect of said windings to be cumulative when the brush set arrives on the terminals of a calling line.

In witness whereof, I hereunto subscribe my name this 3rd day of July, A. D. 1916.

ALBEN E. LUNDELL.

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

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