US832121A - Telephone system. - Google Patents

Description

W W, BEAN. TELEPHONE SYSTEM;

MPLIOATION FILED Dgo. 23, 1902,

UNTTED STATES PATENT ernten.

WILLIAM WV. DEAN, .OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SW ITCHBOARD AND SUPPLY COMPANY, .O F CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented oct. 2, 1906.' A

Application filed December 23, 1902. Serial No. 136,332.

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Be it known that I, WILLIAM W. DEAN, a citizen of the United States of America, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements in Telephone Systems, of which the following is a specification.

My invention relates to improvements in telephone systems whereby the lines which are of the common-battery multiple-switchboard type are provided with only a single relay or electromagnetic signaling device. The apparatus for a telephone-line usually requires a line-relay to operate the line-signal and a cut-ofi relay actuated during a connection for conversation to rendersaid relay or signal inoperative. In my invention I provide a single device which is capable of performing all the functions of the two devices of the ordinary line.

My invention is shown in the accompanying drawing, which represents diagrammatically a telephone system embodying my improvements and in which the same reference characters are used throughout to designate similar parts.

The subscribers lines L and L2 extend from their respective substations A and C to the central ofiice, where they are fitted with the usual spring-jacks or connection-terminals, such as J, J2, and J3, in any desired number and with a line-signal S, which is preferably in the form of a small incandescent lamp having its circuit controlled through the normally open contacts of the relay R. The line conducton2 includes a hi hresistance winding 4 ofthe relay R an is then connected by conductor 5 with the live pole of a battery B, preferably common to the exchange or to a large number of lines thereof. A line conductor 3 includes the helix 6 of low resistance of said relay R and is thence connected to ground or the common office return. These windings or helices 4 and 6 are differentially disposed on the core of the magnet with reference to steady currents in the metallic line and arc preferably wound end on to prevent the passage' therethrough of the voice-currents. At the substation of the line any suitable common-battery outfit maybe employed and which is die, agrammatically indicated in the drawing.

This spcial apparatus includes a transmitter '7 vand receiver 8 in a bridge of the lineconductors, which is normally open at the switch-hook 9, while'an ordinary call-bell 10 and condenser 11 are connected, preferably, in'a permanent bridge 'of the line conductors. Both lines, and, in fact, all lines of the exchange, are ofv the same type, and hence the description ofone sufIices for al1.

The operators cord circuit, of which there may be as many as desired7 comprises a pair of plugs P and P2, each having tip and sleeve contacts adapted to register with the like contact-surfaces of. the spring-jacks or connection-terminals of the lines and the tipcontacts of which plugs are joined together by the strands t and t2 and the interposed condenser c, while the sleeve-contacts thereof are inductively joined by the similar fleXi-iLL ble strands s and s? and the condenser c2. At the answering end of the cord-circuit a air of supervisory relays r and r2 are bri ged across, and an intermediate point of the bridge is joined by a suitable conductor, such as 12, with the live pole of said'battery B. The tip-relay is preferably of one hundred ohms resistanceand the sleeve-relay of about iive hundred ohms. These relays control the circuit of the supervisory lamp S2, which is normally closed at the contacts of relay r and normally opened at the contacts of relay r2. A similar set of relays r3 and r4 are connected across the calling end of the cord-circuit, an intermediate point of which connection joined by conductor 13 with the live poleof said battery B. These relays similarly control the local circuit of the supervisory lamp S3, associated with the calling end of the cord-circuit.

For testing purposes the tip-strand t2 of the cord-circuit is severed at the spring 14 of sleeve relay r, which normally connects, Ithrough conductor 15, with the high-resistance and high -impedance test relay 1'5, which is grounded upon its other terminal. The operators transmitter 16 is connected together with a retardation-coil 17 in a conductor 13, leading to the common wire 5a, which is joined to the live pole of the battery B. The said transmitter is shunted by the primary helix of the operators inductioncoil 19 and by a suitablecondenser c3. The

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' bridge of the calling end of the cord-circuit to thereby ring the subscriber's bell.

The subscriber A desiring a connection takes up' his receiver', and thereby closes a path for current from the battery B through the differential windings of the relay R, which, owing to the difference in resistance of the two relays, is unbalanced and attracts its armature to close a local circuit of the line-signal. rThe operation of the signal at-A tracts the operators attention, whereupon the answering-plug P of her cord-circuit is inserted ink the answering-jack of the line. This act places the supervisory relay fr in shunt of the high-resistance winding 4 of the relay R and the supervisory relay r2 in series with the lowresistance helix 6 of the said relay R. These relays and windings are so proportioned that under these conditions the magnetic effects of the current flowing through the two windings 4 and 6 of the re lay R are equal and opposite, thus neutralizing the said relay and causing its armature to fall away and open the circuit of the lamp S to extinguish it.

Upon learning the number of the party wanted the line is tested in the usual way by touching the tip of the calling-plug to the test-ring of the multiple-jack before the operator. When the line is busy, the test-rings are raised to the potential of -the battery B and a flow of current results through the testrelay T5, which responds and closes the cir-A cuit for current through the primary helix of the operators induction-coil, and thereby causes a click in her receiver'. lf the line is idle, however, the test-rings are at the same potential as the tip of the plug, and consequently no fiow of current results and 'no click is received, Upon finding the line idle, the calling-plug P2 is inserted in one of the multiple-jacks of the line and the ringing-l ey depressed to call the wanted subscriber. The relay R of the called line does not respond to the ringing-current, so that the line-signal of that line remains unexposed and only the subscribers bell is operated. After ringing the subscriber and before his response current liows through the sleevestrand of the cord-circuit operating the sleeve supervisory relay r4; but the relay R is so adjusted that the current through the winding 6 is not now sufficient to operate the same, and therefore the line-signal of the line called does not respond. The supervisory lamp S3 is now lighted toindicate the failure of the calledsubscriber to respond. rl`he tip-strand` t2 is closed for talking purposes through spring 14 and its forward contact of the relay r4. Uponthe response of the called subscriber current flows over the metallic line and operates the supervisory relay rf to open the circuit of and extinguish the lamp S3.

During conversation the battery B furnishes current through the supervisory relays r and yr and over the telephone-lines for transmission purposes, the return-path for current being through the low-resistance winding 6 of the relay R. The line resistance is shunted by that ofthe sleeve supervisory relay or r4; but with an average line a sufficient margin is obtained for satisfactory operation.

At the termination of the conversation the return of the receivers to the hooks opens the line-circuits, thereby deenergizing the tip supervisory relays and permitting the supervisory-lamp circuits tobe closed. Uponobserving these signals the operator takes down the connection and restores all parts to normal condition. It will be understood that the relays 12 and 1f* remain energized when the line-circuits are open by current through the local path, including said relays and the winding 6 of the line-relay, the latter, as before explained, being adjusted so as not to respond to this current.

While the resistances mentioned are notI intended to be arbitrary, good results have been secured., as before explained, when the supervisory relays are 100 and 500 ohms re-v sistance and the windings of the relay R of 100 and 500 ohms, respectively. Under these conditions a sufficient margin is obtained when the total line resistance varies between 0 and 1300ohms,the other apparatus being of the usual or desired dimensions. rl`he grounds mentioned may be one and the saine or the common ofiice return, and the substation apparatus maybe of anydesired common-battery type.

I claimi l. In a telephone system, the combination with a telephone-line, ofan electromagnetic line signaling device having differentiallydisposed windings and of different magnetic effects when calling-current from the substation flows through said windings, and means for equalizing the magnetic effects of said windings' when a connection is established with the line to render the same inop erative, substantially as described.

2. In a telephone system, the combination with a telephone-line, of an electromagnetic line signaling device therefor having differential windings capable of developing different strengths of magnetic field when traversed by current in series, and means for equalizing the magnetic effects of said wind IIO ings when a connection is established with the line, substantially as described.

3. In a telephone system, the combination with a tele'ihone-line, of a line signaling device having two windings capable of producing dil'erent magnetic eli'ects when traversed by the same current, a common source of current at the central oliice, means to operate said device by causing the same current to traverse said two windings in series, and means to render said device inoperative by causing a different current to traverse the two wind ings, substantially as described,

4. In a telephone system, the combination with a line signaling device having two diilerential windings disposed in the path ol cur-'l' ront when the subscriber is calling the central o'lllce, said windings being adapted to produce different magnetic effects" as said current passes therethrough, and means for rendering said device inoperative when connection is established with the line, substaiitially as described. i

5. In a telephone system, the combination with a telephone-line, of a line-relay therefor having two differential windings serially disposed in the path of current when the subscriber is calling the central ollice and responsive thereto, and means for rendering the same inoperative when a connection is established with the line, substantially as described.

6. In a telephone system, the combination with a telephone-line, of a/-line signaling device therefor having' unequal di'li'erential windings disposed serially in the path of current when the subscriber is calling the central o'tlice, 'said device being responsive to such current, and means for rendering said device inoperative when a connection is established with the line, substantially as described. i

7. In a telephone system, the combination with a telephone-line, of a linevsignaling device therefor having two dil'erential windings, ineans for causing a current to iiow through both said windings so as to produce a magnetic field in each and operate the same when a subscriber is calling central oilice, and means for causing current to flow through said windings so as to neutralize each other and render the same inoperative when a connection is establishedwith the line, substan tially as described.

8. In a telephone system, the combination with a telephone-line, of a-line signaling device therefor having two unequal windings differentially' disposed with reference to current in the line when the subscriber is calling the central oilce?, said device responding to such current and means for causing current through said windingsto produce equal and opposite 'effects when a connection is established with the line, wherebythe same is rendered inoperative, substantially as described.

9. In a telephone system, the combination with a telephone-line, of a line signaling device therefor having two unequal windings differentially disposed with reference to current in the line when the subscriber is calling the central ollice, whereby the same responds to such calling-current, a-cord-circuit to establish conversational circuits with the line, supervisory apparatus associated therewith, and means whereby when a connection is established. by the cord-circuit with the line, the magnetic effects of the two windings of the said device are neutralized and the supervisory apparatus is suitably actuated, substantially as described.

l0. In a telephone system, the combination with a telephone-line, of a line signaling device having two windings, a cord-circuit to establish connections 'with the line, supervisory apparatus associated therewith including a pair of electromagnetic windings, means for connecting one of said windings in parallel with one of the windings of said device in the line-circuit, and means for connecting the other electromagnetic winding in a local circuit in series with the other winding of said device, substantially as described.

11. In a telephone system, the combination with a telephone-line, of a line signaling device having a high-resistance and a lowresistance winding, a cord-circuit to establish connections with the line, a supervisory apparatus, having a high-resistance and a loweresistance electromagnetic winding associated therewith, and means when the cordcircuit is connected with the line to connect said low-resistance supervisory winding in shunt of the high-resistance winding of said device and the high-resistance supervisqry device in series with the low-resistance wi1iding of the line signaling device, substantially as described.

12."In a telephone system, the combination with a telephone-line, of a line signaling device therefor, an electromagnet having windings thereon capable of producing dif ferent magnetic effects when traversed by the same current,'a central battery, means to operate said magnet by current from said battery when a subscriber is calling the central oilice, and means to render said magnet inoperative when a connection is established with the line for conversation, said means being adapted to vary the current relation in said coils, substantially as described.

13. In a telephone system, the Acombination with a telephone-line, of a line signaling device having a high-'resistancewinding and a low-resistance winding, one in each side of the line-circuit, a cord-circuit having a pair of supervisory relays associated therewith,

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one of low resistance and the other of high resistance, a source of .current associated with said relays and means for connecting the low-resistance relay iii parallel with the lsaid high-resistance winding when a connection is established with said line, and ahighresistance relay in shunt with the line resistance and in series with said low-resistance winding, substantially as described.

14. n a telephone system, the combination with a telephoneline, 40i a magnetic line signaling device therefor, two windings for said device, means yto energize the device when equal current flows through said windin s and to denergize' the device by causing di erent currents to How through the two windings, substantially as described.

l15. In a telephone system, the combination with a telephone-line, of a line signaling device having a high-resistance winding and a low-resistance winding, one in each side of the line-circuit, a cord-circuit having apair of supervisory relays associated therewith, one of low resistance and thel other of high resistance, a source of current associated with said relays and havingone pole connected directly thereto, and means for con` necting the loweresistance relay in parallel with the said high-resistance winding when a connectionis established with said line, and the high-resistance relay in shunt with the line resistance and in series with said lowresistance winding,substantially as described.

Signed by ine at Chicago, county of Cook, State of Illinois, this 15th day of December,

WILLIAM W. DEAN.

Witnesses:

ROBERT LEWIS AMES,

GAZELLE BEBER.

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