US1386689A - Telephone system - Google Patents

Description

R. D. CONWAY.

TELEPHONE SYSTEM.

APPLICATION FILED JUNE 6. 1918.

156,689., Patented Aug. 9,1921.

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"entree ears ROY I). CONWAY, OF CHATHAM, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. 1., A CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

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Application filed June 6, 1918.

To all whom it may concern Be it known that I, ROY D. CONWAY, a citizen of the United States, residing at Chatham, in the county of Morris, State of New Jersey, have invented certain new and useful Improvements in Telephone Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems but more particularly to such systems of the central energy type as employ service observing means.

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

In accordance with a feature of the invention a voltmeter relay is provided which, when current flows through its winding in one direction, upon the connection of the cord circuit with the line circuit, will be energized to cause the operation of other relays which will in turn cause the illumination of a lamp at the service observing operators desk and which later, upon the disconnection of the cord circuit from the engaged line,.receives a current in the opposite direction to deenergize the relays, thereby causing the effacement of the lamp.

For a more complete understandlng of the invention reference should be had to the following description taken in connect on with the accompanying drawing, in whlch Figure 1 showsonly such portion ofa telephone system as is necessary for the proper understanding ofthe inventlon; and Fig. 2 illustrates a second embodiment of the in- ,vention.

Referring-now to Fig, 1, at A is .shown a subscribers station whose line. B terminates at a central office at which a cord circuit C is located for the purpose of extending the telephone lineB- Associatedwith the line B is the usualline relay 4 which controls the actuation of the line signal 5. A cutofi relay 6 of the ordinary type is also provided for severing the energizing circuit of line relay 4:. A voltmeter relay 7 is shown-connected with the sleeve conductor of jack 8 for controlling the operation of relays 10 and 11 and in turnthe service observing lamp 12.

Assume that subscriber A initiates a call by removing the receiver from the switchhook, thereby causing the operation, of line Specification of Letters latent.

Patented Aug. O, 1921.

Serial no. 238,495.

relay 4; to'establish a circuit for the line lamp 5, which is thereupon illuminated. The operator, upon observing the lighted condition of this lamp, inserts the answering plug 9 of the cord circuit G into the line jack 8, thereby causing the operation of cutoff relay 6 which opens the energizing circu t for line relay 4 for causing the extinguishment of the line lamp 5. Since the contacts of the switchhook at station A are closed, supervisory relay 13 operates to short-circuit the supervisory lamp 522 which is prevented from being illuminated. A circuit including the winding of the voltmeter relay 7 is also established upon the insertion of the plug into the line jack, extending from battery through the alternate contact of supervisory relay 13, sleeve contacts of plug 9 and jack 8, winding of relay 7 and resistance 14, to ground. The current flow ing through the winding thereof is in such a direction, and .the permanent magnet thereof is so poled, thatthe contact arm of relay 7 is caused to'swing into engagement with contact 16, thereby establishing a circuit for relay 10 extending from. battery through resistance 18, contact 16 and winding of relay 10, to ground. The operation of relay. 10 completes an energizing circuit for relay 11 extending from battery, through the winding of relay 11 and contactof relay 10 to ground- Relay 11 on being energized accomplishes two results, first, the establishment of a circuit for the lamp 12, located at the service observing operators desk, and second, establishes a locking circuit for relay 10 extending from battery through resistance 18, the middlelalternate contact of the relay 11, winding of relay 1O to ground. The operation of theselast men- 'lilOIlGd relays completes a circuit which in conjunction with the other apparatus associated therewith, forms what is wellknown in the electrical art .as a Wheatstone bridge with the winding of the voltmeter relay 7 forming the bridged connection. The resistances of the several branches are so proportioned that the current flowing through the bridged connection is thereby reduced to zero, causing the deenergization of voltmeter relay 7. The subscriber at A. in restoring the receiver to the switchhook upon the completion of the conversation, causes the deenergization of relay 13 which shortdirection which is opposite to that of the inicircuits resistance 21. The short-circuiting of this resistance thereby causes the operation of supervisory lamp 22 which serves as a disconnect signal. The resistance of the supervisory lamp 22 is approximately the same as resistance 21 so that the balance of the bridge circuit, as previously described, is maintained even though resistance 21 is short-circuited.

The operator upon receiving the usual disconnect signal withdraws the plug from the jack 8 and in so doing, causes a current to flow through the winding of relay 7 in a tial energization thereof. This circuit may be traced from batterythrough the left-hand contact of relay 11, resistance 15, winding of voltmeter relay 7 and cutoff relay 6 to ground, thereby repelling the armature so as to engage contact 17 which in turn short-circuits the winding of relay 10 which releases to restore all of the apparatus associated there'- with to normal.

Referring now to Fig. 2, which shows in detail the respective branches of the circuit employed in connection with the service observing part of the system, the loop of four resistances which make up the Wheatstone bridge are represe'ntedby' the resistance R, which in Fig. 1 represents the resistance 21, R representing the winding of cutoff relay 6, R and R representing the predetermined resistances 1A and 15, with Y the winding oftheyvoltmeter relay 7 forming th bridged connection which is usually termed the galvanometer branch of such an arrangement. The operator upon inserting a plug into alink jack closes the contacts 19 and 20 whichare represented by the sleeve contacts of the plugand jack, which causes a current to flow through the alternate contact 'of relay 13, resistance R to the junction "point of the bridge, where it. divides, a portion flowing through the winding of "relay -7 and resistance R to ground, but the larger "percentage thereof flowing through resistance R toground, causingan unbalanced condition to exist, which causes the displacement of the contact arm of the voltmeterrelay 7 "from its normal unactuated position into engagement with contact 16. Theen- The operation of relay, 11 not only es-,

tablishes'a lockingcircuitfor relayf10 but also closes thecircuit for connecting in circuit resistance R which forms the fourth branch of the Wheatstone bridge. The resistance R is so proportioned that when it is connected in circuit with the other branches the current flow through the winding of relay 7 is thereby reduced to zero, which allows thec ontact arm thereof to be restored to normal.

v v e a second mentioned relay, gagement of thls contact establishes anen- When the operator removes the plug from the jack, contacts 19 and 20 are opened so that a current is caused to flow from battery through the left-hand contactof relay 11 resistance R winding of relay 7 and re sistance R to ground. A large portion of the current however, flows through resistance R but due to the sensitiveness of the voltmeter relay the amount flowing through the winding thereof is sufficient to cause a deflection of the contact arm. The flow of current through the winding of relay 7 is now in a direction which is opposite to-that previously traced. Contact arm of relay 7 is thereby deflected to engage with contact 17 for short-circuiting the winding of relay 10, which is thereupon deenergizechto restore all other apparatus associated therewith to normal. I What is claimed is: l

1. A telephone exchange system comprising a telephone line, a cord circuit'therefor,

a voltmeter relay energized upon the connection of the cord circu t Wlth tllfi l1ne,a

signaling device, a resistance, and means controlled by the energization of the relay to operate the signaling device and to'connect said resistance in circuit with the relay to the second relay to operate the signaling device and to establish a locking circuit for the second relay. A

.3. A telephoneexchange s stem comprising a telephone line, a cord circuit therefor,

a Wheatstone bridge comprising in two legs thereof cut-off relay and a resistance included in the cord circuit, and in the other legs thereof two predetermined resistances"; a relay, signal control means, a signal associated therewith, and a second relay actuated upon the operation of. the first'meri tioned relay to. energize the signal control means and to formxa locking. circuit for the :4. A telephone exchange system ico p'riing a telephoneline, a cord circuit therefor,

a lVheatstone bridge comprising-fin two legs thereof a cutoff relay andla resistance included in the'cord circuit, inith'e other I legs two predeterminedresistances, a relay in the bridge; a signaling.device, andmeans controlled by the 'relay to operate the signaling device and to equalize 'thepotential at the terminals of the second mention ed relay.

. *5. A service observing system comprising 'a telephone line, a cord circuit therefor, a

relay energized upon the connection of the cord circuit with the telephone line, a predetermined resistance associated therewith, a service observing signal, means controlled by the energization of the relay to actuate the signal and to connect said resistance in circuit with the relay to thereby cause the release thereof.

6. A telephone exchange system comprising a telephone line, a cord circuit, a Wheatstone bridge comprising in the branches thereof a cutoff relay, a resistance included in the cord circuit, and two predetermined resistances, a voltmeter relay in the bridge, an operating circuit therefor completed upon the connection of the cord circuit with the line, a service observing signal, and means operated upon the energization of said voltmeter relay for causing the display of said signal and the equalization of the potential at the terminals of said voltmeter relay for effecting the release thereof, and a second operating circuit for said voltmeter relay established upon the disconnection of the cord circuit from the line for again energizing said relay for causing the release of said means and the effacement of said signal.

7. In a telephone exchange system in combination, a switch having an open and a closed position, a source of current, a relay having arwinding traversed by current of one polarity from said source upon the closure of the switch and by current of an opposite polarity from said source upon the subsequent opening of the switch, and a signaling device energized upon the operation of the relay by current of the one polarity and deenergized upon the subsequent operation of the relay by current of the opposite polarity.

8. A telephone exchange system comprising a telephone line terminating in a jack, a link circuit terminating in a plug for extending the line, a signal, a relay, a normally ineffective operating circuit therefor rendered effective and completed through the contacts of the plug and jack upon the connection of the link circuit with the line to operate the relay thereby causing the operation of said signal, and a second normally ineffective operating circuit for the relay independent of the contacts of the plug and jack and rendered effective upon the disconnection of the link circuit from the line for again operating the relay to effect the extinguishment of the signal.

9. A telephone exchange system comprising a telephone line, a link circuit for extending the line, a signal, a relay, a normally ineffective operating circuit therefor rendered effective upon the connection of the link circuit with the line for causing the energization of said relay, means operated upon the energization of said relay for causing the operation of said signal and the deenergization of said relay, and a second normally ineffective operating circuit for said relay rendered effective by the disconnection of the link circuit from the line for again energizing said relay to effect the release of said means and the extinguishment of said signal.

In witness whereof, I hereunto subscribe my name this 31st day of May, A. D. 1918.

' ROY D. CONWAY.

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