US849336A - Signaling system for telephone-exchanges. - Google Patents

Description

No. 849 336. PATENTED APR. 2, 1907.

y P. R. McBERTY. SIGNALING SYSTEM FOR TELEPHONE EXCHANGES.

APPLICATION FILED JAN.20.1905.

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PATENTED APR. 2, 1907.

F. R. MoBBRTY; SIGNALING SYSTEM FOR TELEPHONE EXCHANGES.

APPLICATION FILED JAN. 20. 1905.

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V UNITED snares PATEN T OFFICE.

FRANK R. McBERTY, OF EVANSTON, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLI- NOIS.

SIGNALING SYSTEM FOR TELEPHONE-EXCHANGES.

Specification of Letters Patent.

Patented April 2, 1907.

Original application filed July 11,1902, Serial No. 115,131. Divided and this application filed January 20,1905. Serial No. 241,962.

To aZZ whom it may concern:

Be it known that I, FRANK R. MoBnR'rY, a citizen of the United States, residing at Evanston, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Signaling Systems for Telephone-Exchanges, of which the following is a full, clear, concise, and exact description.

My invention relates to a signaling system for telephone-exchanges, and has for its object to provide an improved and simple arrangement of circuits and apparatus to be associated with the telephonelines for control- I 5 ling the operation of the visible signals adapted to indicate to the central-oflice operator calls for connection and disconnection.

My invention contemplates a number of telephone-lines each provided at the central office with a ground branch from one line conductor including a magnet adapted when energized to effect the display of a visual callsignal. A branch at the central ollice leads to earth from the other line conductor, and

the substation telephone-switch is adapted when closed to unite said line conductors and complete a circuit for said magnet, including a source of current. A connection-switch is provided at the central o'l'lice adapted when closed to unite the link conductors of the operators cord-circuit with the telephone-line and apply current thereto from a battery associated with the link conductors, which effects the energization of a magnet adapted to 3 5 withdraw said visual signal.

The operator is provided with a supervisory visual signal or signals associated with the link conductors of her cord-circuit, having an indicator-displaying magnet, which upon the closure of the connection-switch to unite the link conductors with a telephoneline is included in a circuit with a source of current independent of the telephone-switch of such line, while the indicator-restoring magnet of such signal is included upon the closure of said connection-switch in a circuit controlled by said substation telephoneswitch. It will thus be seen that upon the closure of the connection-switch the line-sig- 5 nal is Withdrawn and the supervisory signal brought under the control of the telephoneswitch.

I will describe my invention more particularly by reference to the accompanying drawings, wherein Figure 1 is a dia ram of a telephone-exchange system embodying my invention. Fig. 2 is a side elevation of the visual-signal device which I prefer to employ. Fig. 3 is a plan view thereof. Fig. 4 is a front elevation of the signal with the indicator c011- cealed, and Fig. 5 is a rear view thereof.

The telephone-line shown in the drawings extends in two limbs 1 2 from a substation A to the line-springs and test-thimbles a a respectively, of multiple spring-jacks a at the central oliice. A branch conductor 3 leads .from the limb 1 between the spring-jacks and the substation to earth through the magnet I) of the electromagnetic signal device 1) and central-ol'lice battery B, while a branch 4 ex tends to earth through the armature c and its back contact 0 of a magnet c, forming part of said signal device.

The magnet b is adapted when energized upon the closure of the substation telephoneswitch to effect the display of a visual indicator (Z, which in the device shown is carried by a lever I)", normally overbalanced by the armature b of said magnet I), so as to maintain the indicator concealed. Said magnet c is adapted upon its energization to effect the concealment of the indicator (Z and open the ground branch 4,1eading from the conductor 2, the said armature c engaging the indicator and moving it back to its normal concealed position. The magnet c is included in conductor 1 between the ground branch including the indicator-displaying magnet and the spring-jacks and may be shunted by the usual non-inductive resistance.

The apparatus and circuits of the tele phone-line from station C are precisely identical with those just described.

The operator is provided. with a pair of link conductors 5 6, terminating in tip and ring contacts a e and c 6 respectively, of answering and calling plugs c c, each of the con ductors including the usual condenser f. The plugs and spring-jacks together constitute connection-switches adapted when closed to unite the operators cord-circuit with the two telephone-lines. A grounded battery B is associated with the link conductors, its grounded pole being connected by a conductor 7, including the in(licator-displaying magnet b of an electromagnetic supervisory-signal device g similar to the line-signal, with the tip-strand 5 of the cord-circuit, while the free pole of said battery is connected by a conductor 8, including the restoring-magnet c of the said signal device, with the ring-strand 6. The windings of both magnets of the supervisory signal may be of one hundred ohms, but SllOllld have high impedance. In a like manner conductors 7 8 lead from the poles of the battery B through the magnets b c of the supervisory signal 7b to the tip and ring strands 5 6, respectively, the condensers f being interposed between the points where the conductors 7 7 a and 8 8, associated with the plugs e e, join their respective link conductors.

It will be understood that the operator is rovided with the usual listening and ringing {6Y5 for connecting her telephone set with the cord-circuit and for applying ringing-current to the called line. W hile l have shown three batteries in the drawings, it will be understood, of course, that in practice these may be and usually are one and the same battery.

Referring now to Figs. 2 to 5, I will clescribe the mechanism of the visual signal which I prefer to employ in carrying out my invention. The armature b of the indicatordisplaying magnet b is pivoted beneath its center of gravity, so that the armature tends to fall away from the magnet, and in this position is adapted to engage the short end of a pivoted lever b carrying the indicator (Z to normally maintain the same concealed. The indicator-arm is nearly balanced bya small weight at its rear extremity; but the indicator is of such weight that it tends to pass to its lower position upon the attraction of the armature b. The armature c of the restoringmagnet c is pivoted above its center of gravity, so that it also tends to fall away from the poles of the magnet. Said armature carries a short stud 0 adapted upon the attraction of the armature to engage the indicatorlever between its pivotal support and the indicator to force the indicator to its upper or concealed position. The indicator is covered when it lies in its, upper position by a plate i, but when in its lower position lies before an opening 7) in the plate. The armature c is pro vided with a back contact 0 against which it bears whenin its unattracted position. Thus when the magnet c is excited its armature is attracted, breaking contact with its anvil and engaging the lever-arm to restore the indicator to its concealed position.

The visual-signal device shown forms no part of the present invention, but constitutes the subject-matter of my application filed July 11, 1902, Serial No. 115,131, of which this application is a division.

The operation of the system may be briefly outlined as follows: While the apparatus is ,station A desires connection with the subscriber at station C, he first removes his tele phone from its hook, thereby completing a circuit from the central-ofiice battery B, branch conductor 3, through the winding of magnet b of the line-signal device I), over limb 1 of the line to the subscriber, returning over limb 2 of the line, through ground branch 4, including the armature c and back contact 0 of signal-restoring magnet c. The magnet 6 thus becomes energized and attracts its armature b thereby relieving the indicator-arm of its overbalancing-weight, whereupon said arm moves downwardly into a position to display the target (1 before the opening in the plate i. The operator upon observing the signal inserts her answeringplug 0 into answering-jack a of the line and operates her listening-key in the usual way, inquiring the number of the subscriber with whom connection is desired. The closure of the connection-switch a 6 applies current from the battery B, associated with the link conductors, to the line, which current flows from the positive pole of said battery B through the indicator-displaying magnet b of the supervisory signal to the link conductor 5, through contacts a e of the connection-switch, to the limb 1 of the line, through the indicator-restoring magnet c of the linesignal to the substation, returning over limb 2 of the line through the alternative contacts a e of the connection-switch, link conductor 6, branch 8, through the signal-restoring magnet of the supervisorysignal device 9 to the ngative pole of the battery. The magnet c of the line-signal device now being energized attracts its armature c, which engages the indicator-lever and moves the same to withdraw the indicator, at the same time opening the ground branch from the limb 2 of the line to remove the ground connection from the test-piece a of the spring-jack a, a test-potential being created at the thimbles of the jacks by current from battery B. The supervisory-signal device 9 would not, of course, be operated, since current from battery B is traversing both of its magnets b 0, its operation, however, being under the con trol of the substationswitch, which controls the restoring-magnet 0 thereof. A circuit from battery B is now completed through both magnets of the line-signal, contacts a e of the spring-jack a, and plug 6 through the indicator-displaying magnet b of the supervisory signal 9 to earth, the circuit being independent of the telephone-switch at station A.

Assuming that the subscriber with whom,

ICC

multiple jack of the line to station C, whereupon a circuit is completed from the linebattery' B, associated with the called line through the magnet I) of the line-signal device thereof to limb 1 of the line, thence through the indicator-restoring magnet c of the line-signal, through contacts of the calling-plug and multiple jack to strand 5 of the cord-circuit, and thence through the indi cater-displaying magnet of the supervisory signal h to earth. Said magnet thereupon becomesenergized and efl'ects the display of the target of said supervisory signal; but the line-signal of the called line remains inert, since both of its maonets are simultaneously energized. The operator now of course applies the usual ringing-current to the called line to operate the bell at the substation B.

When subscriber at station C removes his telephone from its book, a circuit is co m pleted from battery B to the called station, including both the magnetsof the supervisory signal it similar to the circuit traced with relation to the calling-line, whereupon the indicator is withdrawn.

It will be apparent that the movement of the telephone-switches will control the corresponding supervisory signals, either signal being displayed when the telephone at the station to which it refers is placed on the switch-hook. Neither of the line-signals, however, is displayed after connection has been established.

When the subscribers hang up their telephone-receivers at the termination of the convcrsation, the circuits from battery B, including the restoring and displaying magnets of both supervisory signals 9 h, are broken but the grounded circuits from battery B, including the indicator-displaying magnets of the said supervisory signals 9 it, remain completed, whereupon the indicators of both signals are displayed. The operator upon withdrawing the plugs e e restores the apparatus to its normal condition, the armatures of the indicator-displaying magnets in retracting overbalancing the indicator leverarms and withdrawing the indicators.

It will be observed that while the apparatus is in its idle or inert condition the testrings of the multiple jacks are reduced to the potential of the earth, the line conductor 2, with which they are connected, being grounded through the switch-contacts c of the linesignals of the respective lines. \Vhen connection is made with any line, however, the battery B becomes connected with these test-rings, while at the same time the earth branch from the line conductor 2 is broken. Thereafter the test-rings are electrified to a considerable potential above the earth, so that they will test busy at the other sections of the multiple switchboard in the usual way.

I claim- 1. The combination with a metalliecir cuit line, and means for closing the line at the substation, of a line-signal indicator and a controlling-magnct there'l'or in a permanent ground branch from one of the line conductors, a ground branch'lrom the other line conductor, a magnet adapted to eflace the indicator when displayed, and switch-contacts actuated by said last-mentioned magnet for breaking said ground branch, and means for exciting the said last-mentioned magnet in making connection with the line, as described.

2. In combination with a metallic-circuit line and means for closing the line at the sub station, of spring-jacks in a multiple switchboard ior the line, the test-rings of the springjacks being connected with one of the line conductors, a ground branch from said line conductor, a signal controlling magnet in a permanent ground branch containing a bat tcry from the other line conductor, a magnet adapted to restore the signal, and means for exciting the said last-mentioned magnet in making connection with the line, and switchcontacts operated by said last-mentioned magnet for breaking the ground branch from the test-rings, as described.

The con'ibination with a telephone-line and a spring-jack thereof, and a plug and plug-circuit therefor, of a line-signal-con trolling magnet in a ground branch from the line including a battery, a magnet adapted to el'l'ace the indicator of said signal when displayed, said last-mentioned magnet being serially included in the line between the branch and the spring-jack, and a ground branch from the conductor ol the plug circuit which is connected with said serial magnet, as described. 1

4. The combination with a metallic-circuit line and a switch at the station for closing the circuit, a spring-jack for the line and a plug and plug-circuit for making connection therewith, of the line-signal in a ground branch from one of the line conductors together with a battery, a ground branch from the other line conductor, an indicator-rcstoring magnet for resetting said line-signal serially included in the line between the spring-jack and the ground branch, said indicator-restoring magnet being adapted to break the ground branch connected with the other conductor of the line, and a bridge of the cord-circuit containing a battery, as described.

5. In a supervisory system for telephonelines having telephone-switches for closing the lines, a supervisory signal associated with the plug comprising a pivoted weighted indicator, an overbalancing-armature and a magnet therefor, and a restoring-armature and a magnet therefor adapted to conceal said indicator, of a circuit independent of the telephone switch containing the magnet of said overbalancing-armature, and a switch ICC for closing said circuit and acircuit including said restoring-magnet, said last-mentioned circuit being controlled by the telephoneswitch, as described.

6. In combination with a telephone-line and a telephone-switch at the station thereof, a spring-j ack for the line, and a plug and plugcircuit, a supervisory signal having an indicator, and means for displaying it, an armature engaging said indicator to counteract said means, and a magnet for said armature, a circuit for said magnet closed in registering contacts of the spring-jack and plug, and independent of the telephone-switch, a restoring-armature adapted to counteract said means to conceal the indicator, and a magnet therefor, said lLStfln611tlO118d ,magnet being in a circuit of the line controlled by the telephone-switch, as desired.

7. The combination with a telephone-line extending from a substation to a central office, of a source of current at the central office, of a telephone-switch at the substation controlling said circuit, a visual-signal device for the line at the central oflice, a magnet, an armature therefor normally overbalancing the indicator of the signal device to conceal the same, said armature when attracted being adapted to display the indicator said magnet being controlled by the substation. telephone-switch, link conductors at the central oflice, a connection-switch for uniting said link conductors with the line, a magnet adapted to withdraw the indicator of said signal device, and a circuit for said magnet completed upon the closure or said connection-switch.

8. The combination with a telephone-line extending from a substation to a central office, of a source of current at the central office, of a telephone-switch at the substation controlling said circuit, a visual-signal device for the line at the central oflice, a magnet adapted to display the indicator of said signal device, a circuit controlled by the substation telephone-switch, link conductors at the central oflice, a connection-switch for uniting said link conductors with the line, a magnet adapted to withdraw the indicator of said signal device, a circuit for said magnet completed upon the closure of said connection-switch, a supervisory visual signal associated with the plug-circuit, an indicatordisplaying magnet there-for included in said lastmentioned circuit, and a restoring-magnet for said supervisory signal in a circuit controlled after the closure of said connectionswitch by the substation-switch; whereby the indication of the line-signal is eflaced and the indicator of the supervisory signal is made responsive to the telephone-switch upon the closure of said connectionswitch.

9. In a supervisory system, the combination with a telephone-line and a telephoneswitch at the station thereof, a spring-jack for the line and a plug and plug-circuit, of a signal-controlling magnet in a ground branch from the line with a source of current, a signal-restoring magnet serially in the line between said branch and the spring-jack, a ground branch from the other line conductor, said last-mentioned branch being controlled by the restoring-magnet, a su ervisory visual signal associated with the p rig-circuit, an indicator-displaying magnet thereof in a ground branch from said side of the line containing the signal-restoring magnet, a restorlug-magnet of the supervisory signal in a ground branch from the other side of the plug-circuit, said last-mentioned branch containing the source of current whereby the indication of the line-signal is effaced and the indicator of the supervisory signal is made responsive to the telephone-switch to be displayed when the switch opens the linecircuit, as described.

10. The combination with a telephoneline extending from a substation to a central source of current and a telephone-switch at the substation controlling said circuit, of a visual-signal device for the line at the central oflice comprising a pivoted weighted indicator, an overbalaiicingarmature therefor, a magnet controlling said armature responsive to said substation-switch, a restoring magnet and armature for said indicator, link conductors at the central oflice, a connectionswitch for uniting said link conductors with the line, and a circuit for said restoring-magnet completed upon the closure of said connection-switch.

In witness whereof I hereunto subscribe my name this 27th day 'of December, A. D.

FRANK R. MOBERTY. Witnesses:

W. S. DUNCAN, E. F. BEAUBIEN.

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