US1497284A

US1497284A - Telephone-exchange system

Info

Publication number: US1497284A
Application number: US348566A
Authority: US
Inventors: Polinkowsky Lipa
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1919-12-31
Filing date: 1919-12-31
Publication date: 1924-06-10
Anticipated expiration: 1941-06-10

Description

June 10 1924.

,4 7,284 L. POLINKOWSKY TELEPHONE EXCHANGE SYSTEM Filed Dec. 31. 1919 s sheets-shed 1 mq f r in n v r 2f/ 202' 2037i W 10, mag, 1,497,284

L. POLINKQWSKY TELEPHONE EXCHANGE SYSTEM June 10 1924. 1,497,284

L. POLINKOWSKY TELEPHONE EXCHANGE SYSTEM Filed Dec. 31. 1919 5 Sheets-Sheet 5 4 5 40/ 402 U U l L L 4/ I] f 11 3400 77 4/7 4%0 r q c 106 m i 1 i L Q I 5 Sheets-Sh L. POLINKOWSI TELEPHONE EXCHANGE SYSTEM Filed Dec.

Fig. 4.

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June 10 1924.

ii-me 10 19 24 l... POLJNKOWSKY TELEPHONE EXCHANGE SYSTEM 5 Sheets-Sheet 5 //1 venfon' L/pa Pa/ /hlraws/ry.

Patented June 10, 1924.

- ESTATES Lira roLinnowsxr, or anrwnnr BELGIUM, Assrenon To wears-Rn nncrnrc COMPANY, iNoonronAr-np, or new YORK, N. Y., A CORPORATION on NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed December 31, 1919. Serial No. 348,566.

To all whom it may concern:

Be it known that I, LIPA POLINKOWSKY, a citizen of Russia, residing at 18 Rue .du Bastion, in Antwerp, --Belgium, have in vented certain new and useful Improvements in Telephone-Exchange Systems, of whiclrthe following is a full, clear, concise, and exact description.-

This invention relates to telephone exchange systems, and .more particularly to systems of the type in which automatic switching apparatus is employed for setting up connections.

In automatic telephone systems in which selective switches, operated in accordance with the revertive impulsecontrol principle, are used it is customary to provide register sending devices for the-purpose of controlling these switches. The required designations maybe recorded on the register senders in any suitable manner, as bygmeans'of an operators keyboard, impulse senders at the operators position .or impulse senders located at the subscribers substations. After the designation is recorded, the register sender becomes eilective to selectively control the several selective switches to establish the desired connection.

The object of this invention is the :provision, in a system of this character, of means whereby a selective switch .may be broughtunder the controloi anyone of a plurality of register senders :for the purpose of operatingthis switch to establish any one of a number ofdi-iierentclasses of connections.

A feature of theinvention relates to an arrangement inwhich connections are es tablisliedover a series of selective switches under the control of a register sender,flone of such switches having associated therewith a second register sender, which is normally inoperative during the time such switchis being controlled by the first-sender. According to. this feature, when the ,selectire switch having the registersender RSSO? ciatedthercwith, is taken foruse in theestablishment of a different class of connection, suchsender is automatically placed in condition to control the operation of said switch. d

Other features contemplated by this invention will'become apparent {from thefollowing description and the appended claims.

distant exchange.

shown diagrammatically whereas the .cir-

Rei erring'to the drawings, Figs. 1, 2,3

and at, taken in order from left toright with .Fig. 5 beneath F ig. ft, illustrate a telephone ig. ,1 shows the calling end of a toll opcrators cordcircult in a first exchange and also the outgoing end of a pair of trunks leading to a distant exchange. Fig. 2 shows system .in' which this invention is embodied.

the incoming ends of the trunks terminating in first group selector switches in the One 01": these switches is change. At the right of the vertical broken line in Fig. 3are shown the circuits and apparatus at a testing ope'rators position in the distant exchange. Fig. 4 shows gtW'Q final selector switches, one of which is illustrated diagrammatically and the other in detail. Fig. 5 illustrates a second register sender associated with the circuits of the final selector switch shown in Fig. .4.

In accordance with the arrangement shown in this system, the final selector switch serves both asa toll operators final switch for establishing connections to busy called lines, and also as a testingoperators switch for performing routine tests of the subscribers lines. *lVhen a call is extended to thewtoll operators position, she first inserts the plug of hercord circuit in a jack,

such as 2000f the trunk leading to .afirst group the called subscribers line belongs. The toll operator, by means of her impulse {sender 2.12thereu ion sets uo a re ister sender such as the one shown at the bottom of Fig. 2, in accordance with the required number. The register sender having been positioned, then becomes operative to control the selectiveoperations of the firstgroup selector 210, second group selector 215, and-the final selector 416, to. extend the connection through to thecalled line 420. lithe called line 420 is found busy, as by being engaged in la local connection, overwhich toll calls should be given preference, the toll operselector 210 in the exchange-to which a tween the testing ator removes the plug of her cord circuit from jack 200 and inserts it in the jack 202 of a special trunk circuit. She then sets up a connection over the special first group selector shown in detail in Fig. 2, second group selector 216 and the special final selector switch shown in detail in Fig. 4. This final selector switch is arranged not to make a test of the subscribers line and can, therefore, complete a connection through to a called line regardless of whether such line is busy or idle. The toll operator then informs the called subscriber that a toll call is waiting and instructs him to release the local connection which, at the time, is holding his line engaged. The toll operator now removes the plug of her cord circuit from the jack 202 of the special trunk and inserts it again in jack 200. The original connection is established once more through to the called line at which time the called subscriber will have released the local connection preparatory to receiving the incoming toll call. During the establishment of connections of this character the final selector switch as well as the first and sec- 0nd and such additional group selectors as may be required is controlled by the register sender associated with the circuits of the first group selector switch.

hen the testing operator wishes to make a test of the subscribers lines, he appropriates the use of one of the special final switches for this purpose. In this case the testing operator, by inserting plug 410 of his connecting circuit in either of the

jacks

401 or 402, extends a connection from his position to the special final selector switch The extension of this connection places the register sender, shown in Fig.5, in' condition to be set up by impulses transmitted from the testing operators position in accordance with the digits of the line that is desired to be tested. The register sender having thus been positioned, is then operative to control the selective operation of the final switch to complete a connection beoperators position and the desired subscribers line.

A detailed description will now be given of the operation of the system. Assume first that a toll connection, incoming through the toll operators position in the first exchange, is desired with the subscribers line 420 in the second exchange. The toll operator in serts a plug 201 of her cord circuit in jack 200 of an idle trunk leading to the second exchange. She then manipulates her impulse transmitter 212 to position a register sender (not shown) in accordance with the number of the called line. The register sender thereupon serves to control the operation of the first group selector 210, second group selector 215, and final selector 416.. to complete the connection to the called subscribers line 420. Assuming now that the called subscriber's line 420 is busy at thistime, this busy condition is indicated in any well-known manner to the toll operator who thereupon removes the plug 201 from jack 200 and inserts it in jack 202 of the

special trunk circuit

217, 218.

A circuit is then completed from battery through the winding of relay 204, resist ance 205, sleeve of plug 201, sleeve of jack 202, left-hand winding of relay 235 to ground. Relay 204 attracts its armature and closes a circuit for relay 206. Relay 206, being energized, connects the windings of relay 207 and retardation coil 208 respectively, to the ring and tip sides of the toll operators cord circuit. Relay 235 attracts its armatures and closes a circuit from battery through the supervisory lamps 209, contact 224 (1 to 2) of sequence switch 220, front contact and left-hand armature of re lay 235, to ground at contact- 223, (1 to 2). The lamps 209 indicate that the trunk circuit is busy. A circuit is also completed from battery through the winding of relay 222, contact and right-hand armature of relay 235, contact 225 (1), conductor 217,

tip of jack 202, tip of plug 201, upper closed contacts of key 211, left-hand arma ture and contact of relay 206, retardation coil 208 to ground. The relay 222 becomes energized and closes a circuit from ground over its armature and front contact, contact 226 (1), and winding of sequence switch 220 to battery and ground. Sequence switch 220 moves out of position 1 and into position 3 whereupon the relay 222 is deenergized. The supervisory lamps 209 are now illuminated in a circuit closed to ground at the sequence switch contact 227 (2 to 18).

In position 3 of sequence switch 220 a sender selector 280 of the sequence switch type is started in operation to associate an idle sender with the circuits of the first group selector switch. The circuit for operating the sender selector 280 may be traced from battery through the winding of said sender selector, contact 244 (3), back contact and armature of relay 232 to ground at contact 282, closed in positions 1 to 8.

It may be observed at this point that the sequence switch contacts included within the two horizontal broken lines in Fig. 2 are controlled by the sender selector 280. The sequence switch contacts above the up per broken line are controlled by sequence switch 220. The sequence switch contacts below the lower horizontal broken line are controlled by a sequence switch (not shown) of the register sender.

The sender selector sequence switch 280 commences to rotate and upon moving to a position corresponding to an idle register sender, the relay 234 is energized by means of a circuit from ground over the. contact 282, right-hand high resistance winding of relay 234,. contact 228 (3),. conductor 293, contact 327, and thence by way of lead 328 to battery and ground. The manner in which battery potential is applied to the lead 328 at the: register. sender, is not shown in this.

disclosure; For a full and complete description of testing and: seizing a register sender of. the type illustrated in this disclosure, reference is made to the British patent to lVestern Electric Company, Limited No. 141,081, accepted April 15, 1920. It is suflicient to state herein that an idle register sender will be identified by means of full battery potential on the lead 328. Therefore, when the above traced circuit is closed the relay 234 is energized and completes a circuit through its left-hand low resistance winding and the winding of reconductor 293' that other searching sender selectors will not be able to seize this reg i'ster sender; Relay 232 becomes energized and opens the circuit of the sender selector switch 280, causing the latter to come to rest. Relay 232 also closes a circuit from battery through the winding of sequence switch 220, contact 226 (3), front contactand armature of relay 232, to ground at contact 282. Sequence switch 220 advances from position 3 into. position 4. In position 4 of sequence switch 220, the following circuit is completed: battery, through the winding of relay 207, at the toll operators position, contact and right-hand armature of relay 206, lower closed contacts of key 211, ring of plug 201, ring of jack 202, conductor 218, contact 229 (4), conductor 329, right-hand winding of stepping relay 325, contact and left handarmatureof relay 339 to ground. Relay 207 attracts its armatureand opens the circuit of lamp 214. The lamp 214, by ceasing to glow, indicates to the operator that an idle register sender has been found and associated with the first group selector.

The operator by depressing the listening key 203, closes a circuit from battery through the left-hand winding of stepping relay 325, conductor 330., contact 225 (4 conductor 217, tip of jack 202, tip of plug 201, upper closed contacts of key 211, upper contact of listening key 203, through the operators telephone set (not shown), the lower contact of listening key 203, lower closed contacts of key 211, ring of plug20l, ring of jack 202, conductor 218, contact 229 (4), conductor 329, righthand winding of relay 325, contact and left-hand armature of relay 339 to ground. When the register sender sequence switch (not shiown) has lates the sender 212 to position the registers of the register sender in accordance with the designation of the called line. After the registers have been positioned, the fundamental circuit is closed for controlling the brush-selecting operation of the first group selector as follows: battery, through the winding of relay 222, contact and right-hand armature of relay 235, contact 247 (4), 0011- ductor 296, contact 361, winding of stepping relay armature and contact of relay 357, to ground at contact 362. The relay 222 completes a circuit from ground over its armature and front contact,contact 226 (4), through the winding of sequence switch 220 to battery and ground, for driving sequence switch 220 into position 5. In position a circuit is completed from battery, through the winding of the trip spindle power magnet 248, contact 249 (5), front contactand armature of relay 222 to ground. The power magnet 248 causes the trip spindle 251 to be rotated to a position for tripping the desired set of brushes. Each time the trip spindle 251 advances from one trhqping position to another, a circuit is completed from battery, through the winding of relay 222. contact 237 (5) to ground at the interrupter contact 250. 2 This circuit maintains the energization of relay 222 and causes the shunting of the stepping relay 355 in the fundamental circuit. In the manner described in the abovementioned British patent, the operation of the stepping relay 355 causes the register to be returned to its normal position. The fundamental circuit is then opened atthe register sender and as soonas the tripping spindle is positionedin respect to the desired set of brushes, the interrupter contact 250 opens and causes the release ofthe relay 222. The relay 222 by being deenergized, closes a circuit from ground over its armature and back Contact, contact 238 winding of sequence switch 220 to battery and ground. Sequence switch 220 advances from position 5 over position6' into position 7. As soon as sequence switch 220 reaches position 6,

relay 222 is again energized in a circuit from battery, through the winding of said relay, contact and right-hand armature of relay 235, contact 247 (6), conductor 293, contact and right-hand armature of relay 339, to ground at the contact 445. Relay 222 therefore becomes energized and opens the circuit closed over contact 238 when sequence switch 220 reaches position 7, insuring that &

said sequence switch will not pass beyond position 7.

In position 7 the selected set of brushes are driven over the terminals of thetrunk group to search for an idle trunk leading to a second group selector. The brush car riage power magnet 241, which causes the movement of the selected set of brushes, is energized in a circuit from battery through the winding of said magnet, contact 244 (7), back contact and armature of relay 232, to ground at contact 282. Upon the-test brush 252 making engagement with thetest terminal of an idle trunk, full battery potential will be found thereon and test relay 234 is energized in a circuit closed at contact 228 (7), through the right-hand high resistance winding of said relay to ground at contact 282. Relay 234 attracts its armature and completes a low resistance path from test brush 252, contacts 228 (7) through the left-hand winding of relay 234, contact and armature ofthis relay and the winding of relay 232 to ground. This low resistance circuit reduces the potential in the well-known manner on the test terminal of the selected trunk to render the same busy to other switches. Relay 232 by being energized, opens the circuit of the power magnet 241 and closes a circuit for the holding iagne't 245 which serves to bring the brushes to rest accurately centered on the terminals of the selected trunk. The circuit of magnet 245 may be traced from battery through the winding of magnet 2145, contact 240 (7), contact 226 (7), front contact and armature of relay 232, to ground at contact 282. Relay 232 also closes a circuit from battery through the winding of sequence switch 220, contact 226 (7), front contact and armature of relay 232 to ground at contact 282, moving said sequence switch from position 7, over position 8 and into position 9.

The fundamental circuit is now closed at

sequence switch contacts

255 and 256 from the register sender through to the second group selector shown diagrammatically at 216. In the well-known manner the brush selecting and trunk-hunting operations take place at the second group selector to extend the connection over an idle trunk 413, 414, to a final selector switch. When the test brush 230 of the second group selector makes engagement with the test terminal 231 of trunk 413, 414, in the trunk-hunting operation, a circuit is closed from battery, throu h resistance 442 at the final selector switc contact 441 (1) of sequence switch 450, conductor 440, test terminal 231, test brush 230, contact 233, right-hand high resistance winding of relay 246 to ground. In parallel to this circuit, a circuit is also completed for relay 443. Relay 443, however, is not energized in series with the right-hand high resistance winding of relay 246. Relay 246 attracts its armature and closes a circuit through its low resistance left-handwinding and the winding of relay 236 to ground, in

parallel to the circuit through the righthand winding of relay 246. This low resist ance circuit reduces the potential on terminal 231 suliiciently to render the selected trunk busy to other switches, and also permit-s the rela- 443 to attract its armature.

Relay 443 y being energized, closes a circuit from ground over the left-hand armature and back contact of relay 446, armature and front contact of relay 443, contact 453 of sequence switch 450, through the winding of said sequence switch to battery and ground. Sequence switch 450 moves out of position 1 and into position 3. In position 3 the fundamental circuit for controlling the operation of the final selector is closed as follows: battery, through the winding of relay 452, contact 471 (3), back contact and left-hand armature of relay 477, contact 444 (3), conductor 414, middle terminal and brush of the second group selector 216, contact 242, terminal 253, brush 254, contact 256, (9), conductor 296, cont-act 361, through the winding of stepping relay 355, armature and contact of relay 357-, conductor 297, contact 255 (9), brush 257, terminal 258, contact 244, upper brush and terminal of group selector 216, conductor 413, contact 445, (3), conductor 612 to ground. Relay 452 is energized and completes a circuit from ground over its armature and front contact, contact 456 (3), winding of sequence switch 450, to battery and ground, for moving sequence switch 450 out of position 3 and into position 4. In position 4, the trip spindle power magnet 448 is energized in a circuit from battery through the winding of said magnet, contact 447- (4), to ground at the front contact and armature of relay 452. The trip spindle is rotated and for each position passed over, the interrupter contact 455 closes the following circuit to ground, to shunt out the stepping relay 355 at the sender: battery, through the winding of relay 2, contact 449 (4), to ground at interrupter contact 455. hen the register has returned to its normal position the fundamental circuit is opened at the register sender and upon the next opening of the interrupter contact 455, relay 452 is de energized. A circuit is thereupon closed from ground over the armature and back contact of relay 452, contact 456 (4), winding of sequence switch 450, to battery and ground. Sequence switch 450 moves from position 4 into position 5.

The fundamental circuit is again closed preparatory to controlling the operation of the selected set of brushes in the units selection movement. Relay 452, again being energized in the fundamental circuit, closes a circuit from ground over its armature and front contact, contact. 456 (5), winding of sequence switch 450, to battery and ground. Sequence switch 450 advances'from position 5 and into position 7. In this position the power magnet 461, which causes the operation of the brush carriage, is energized in a circuit from battery through the winding of said magnet, contact 451 (7), to ground at the front contact and armature of relay 452. For each set of terminals passed over by the

brushes

476, 479, and 470, the interrupter contact closes the following circuit, in shunt of the stepping relay 355: battery, through the winding of relay 452, contact 449 (7), to ground at the interrupter contact 457. hen the unit's register has been restored to its normal position the fundamental circuit is opened at the sender and upon the next opening of the interrupter contact 457, the relay 452 is 'deenergized. A circuit is then closed from ground over the armature and back contact of relay 452, con tact 456 (7) winding of sequence switch 450, to battery and ground. Sequence. switch 450 moves from position '7 into position 10. hen units selection has been completed the sequence switch controlling the register sender advances to a position where a cir cuit is established for the energization of relay 339. This takes place in the manner described in the aboveanentioned British Patent No. 141,081, accepted April 15, 1920.

Relay 339, at. its right-hand armature, opens,

the circuit which up 'to this time has been holding the relay 222 energized. Relay 222 releases its armature and closes a circuit from ground over its back contact, contact 238 (9) winding of sequence switch 220, to battery and ground. Sequence switch 220 thereupon advances into position 11. Provided the tolloperator has released her dialing key 211 by this time, the following circuit will be closed for relay 2221 Battery,

through the winding of said relay, contact 237 (11), conductor 217, tip of jack 202,

. said'key is released and then advances into position 13 in the manner just explained. As sequence switch 220 leaves position 9, it opens at contact 229, the above-traced circuit for relay 207 over conductor 218. This relay by releasing its armature closes a circuit for the supervisory lamp 214. The illumination of lamp 214 indicates to the operator Sequence that selection is completed and that the talking connection is established through to the called line. She now converses with the subscriber at substation 420 and informs him that atoll call is waiting to be extended to his line. The called subscriber closes his conversation with the local subscriber, while the toll operator withdraws plug 201 from jack and reinserts it in the jack 200. The operator again builds up a connection over group selectors such as 210, 215 and final selector 416 to the called line 420 and conversation with the distant calling subscriber may take place.

The removal of plug 201 from jack 202 opens the circuit of

relays

204 and 235. Relay 204is deenergizedand causes the deenergization of relay 206. Relay 235 by releasing its left-hand armature closes a circuit from ground, contact 223 (13), lefthand armature and back contact of relay s35, contact 238 (13), winding of sequence switch 220 to battery and ground. Sequence switch 220 advances from position 13 into position 17. In this position the brush carriage of the first group selector is restored to its normal position. The circuit for energizing the brush carriage power magnet 241 is traceable from battery through the winding of said magnet, contact 244 (17), back contact and armature of relay to'ground at contact 282. Upon the brush carriage reaching its home position, a circuit is completed from battery, over contact 243 (16 to 18), brush 269, winding of relay 232 to ground. Relay 232 attracts its armature and opens the circuit of. the 'power magnet 241, causing the brush carriage to cease to rotate. At the same time relay 232 closes a circuit from battery, through the winding of sequence switch 220, contact 226 (17), front contact'and armature of relay 232 to ground at contact 282. Sequence switch 220 advances from )osition 17 into position 1. When the

rushes

257 and 254 leave the terminals 258 and 2530f the connecting circuit lead-' ing to the second groupselcctor, a condition is brought about in the well known manner for causing the release of said selector. After the second group selector has been released andthe test brush 230 has disengaged te'st terminal 231;, the holding circuit of relay 443 is broken permitting this relay to become deenergized. A circuit is then closed from ground over the lefthand armature and back contact of relay 446,

armature and back contact of relay 443, contact 421 (2m 11), winding of sequence switch 450 to battery and ground. Sequence switch 450 moves from position 10 over position 11, and into position '17. In this position the brush carriage of the final selector is restored to normal by means of a circuit from battery, through the winding of the brush carriage power magnet 461, contact 451 (17), back contact and armature of relay 452 to ground. In the normal posi tion of the brush carriage a circuit is completed from battery through the winding of relay 452, contact 449 to ground at the interrupter brush 457. Relay 452 attracts its armature to open the circuit of the power magnet 461, causing the brush carriage to cease to rotate. Relay 452 also completes a circuit from ground over its armature and front contact, contact 456 (17), winding of sequence switch 450 to battery and ground. Sequence switch 450 thereupon returns to its normal position 1. c

It will now be considered that the testing operator whose position is shown in Fig. 3, wishes to make a routine test of a group of subscribers lines. For this purpose the operators position is equipped with the usual testing apparatus diagrammatically indicated at 409." A connecting circuit leading from the operators testing equipmentterminates in the plug 410. The operator by inserting the plug 410 in either of the

jacks

401 or 402, which are connected in n'rltiplewith the trunk 413', 414, appropriates for his use a final selector switch having access to the desired group. of subscribers lines. In the particular type of switch used in this system, the terminal bank is arranged to accommodate 200 lines. These lines are divided into two groups of 100 each, an even hundred and an odd hundred. If the operator wishes to make tests in the even hundred, he inserts the plug 410 in jacks 402 whereas if he desires to test the line in theodd hundred group, the plug 410 is inserted in jack 401.

Assuming that the plug 410 is inserted in jack-402, a circuit is thereupon completed from battery, over the sleeve of plug 410,

sleeve of jack 402, winding of relay 446 to ground. Relay 446 is energized and closes a circuit from ground'overits left-hand armature and front contact, contact 458 (1), left-hand winding of relay 477 to battery and ground Relay 477 is energized and closes a holding circuit -tor itself as follows: battery through resistance 442, contact 441 (1), right-hand armature, front contact and right-hand winding of relay 477 to ground. Relay 446 also closes a circuit from battery through the winding of relay 452, contact 471 (1), right-hand armature and contact of relay 446, contact 478 (1), conductor 414, tip of jack 402, tip of plug 410, left hand arm of switch 417 to ground at the operators equipment 409. Relay 452 is energized and a test is made to determine the busy or idle condition of the register sender shown. in 5. This sender is common to .a plurality of final selector switches such as the one'shown in Fig. 4. The circuit for making the test may be traced from ground over the armature and front contact of relay 452, contact 459 (1), rigl'it-hand high resistance winding of relay 464, contact 467 (1), conductor 493, contact 622 .(1) of sequence switch 620, windings of relay 634 to battery and ground. It the sender is idle, full potential will be found on the conductor 493, and the high resistance winding of relay 464 receives sutficient current to become energized. Relay 464 by attracting its armature completes a low resistance path to ground through its left-handwinding, the winding of relay 462, and contact 466. This low resistance path being in shunt with the right-hand winding of relay 464, reduces the potential on conductor 493 to render the register sender busy.

When relay 462 is energized it closes a circuit from ground over its armature and contact, back contact and armature of relay 482, windingof relay 431 to battery and ground, Relay 481, which is slow-to-operate, attracts its armature after an interval and completes through the winding of sequence switch 450,

contact 453 (1), front contact and armature of relay 481 to ground at contact 463 (1). Sequence switch 450 advances from position 1 into position 3. In positions 2 to 18 oi sequence switch 450 the following circuit is maintained for busy guard lamps 400 individual to trunk 413, 414; battery through lamps 400 to ground at contact 463. hen sequence switch 450 reaches position 3, a circuit is closed from battery through coil 624, contact 639 (1), winding of stepping relay 625, contact 638 (1), front contact and left-hand armature of relay 477, contact 444 (3), conductor 414, tip of jack 402, tip of plug 410 to ground at 409. Relay 625 completes a circuit from ground over its armature and front contact, armature and back contact ofrelay 626, contact 636 (1), winding of sequence switch 620 to battery and ground. position 1, into position 3. In position 3 of sequence switch 620, the interrupter is connected in series with battery and the primary winding of dialing tone coil 624 over contact 632. A dialing tone is thereby transmitted to the testing operators equipment to inform him that the sender is ready to receive impulses.

The testing operator thereupon throws the switch 417 to include the impulse sender 418 in series with the trunk 413, 414. The following impulse circuit is now completed for the transmission 01 impulses to the stepping relay 625: battery through the coil 624, contact 639 winding of relay 625. contact 638 (3), front contact and left hand armature of relay 477, contact 444 (3), con' ductor 414, tip of jack 402, tip of plug 410, left-hand arm of switch 417, through the a circuit from. battery,

Sequence switch 620 moves from.

nkl.

switch 417, ring of plug 410, ring of jack" 402, conductor 413, contact 445 (3), conductor 612 to ground. Relay 625 isenergized and closes a circuit from ground over its armature and front contact, arn'iature and front contact of

relay

6,26, contact 613 (3), right-hand winding, armature and contact of relay 629, contact 628 winding of the tens register Z30, to battery and ground. It will be observed that the relay 626 was energized when sequence switch 620 moved into position 3 in a circuit including contact 611, the armature and back contact of relay 623. In parallel to the circuit above traced through the right-hand winding of relay 629, a circuit is also closed from ground and battery through impedance coil 631 and through the left-hand winding of said relay to ground at the armature and front contact of relay 625. Relay 629 is made differential and does not attract its armature when both windings are simultaneously energized. The tens register 730 however is energized and advances from position into position 1. The master contact 731 of register 730 in closing between position 0 and position 1 short-circuits the right-hand winding of differential relay 629, permitting this relay to attract its armature. The register 730 continues to move into position 1 under the control of its master contact. operator manipulates {the impulse sender 418 to transmit the tens impulses, the step ping relay 625 releases its armature on each interruption of the impulse circuit. The circuit through the left-hand winding of differential relay 629 is opened at the first interruption and this relay releases its armature. Upon the next closure of the impulse circuit, the relay 625 is again energized and closes the above traced circuit for the register 7 and relay 629. V The register 730 advances from position 1 into position 2, and relay 629 is again energized over its left-hand winding. At the next interruption of the impulse circuit relay 629 is again deenergized and this procedure continues, the register 730 being moved forward one step for each impulse contained in the tens series. The impulse sender 418 is soconstructed that the last interruption of the impulse circuit in each series is of a compa -atively longer duration than the preceding interruptions. On this last interruption, the following circuits for relay 634 is maintained closed for a sufiicient interval of time to permit said relay to attract its armature: battery through the windings of relay 634, contact 622 (3), back contact and armature of relay 625 to ground. Relay 634 be ing constructed to attract its armature slowly, does not operate on brief closures of its energizing circuit. Relay 634when energized closes a circuit from battery through hen the the right-hand winding of relay 623 to ground at the armature and front contact of relay 634. Relay 623 closes a circuit from ground over its armature and front contact and left-hand Winding, contact 636 (3), winding ofsequence switch 620 to battery and ground. Sequence switch 620 moves out of position 3. The circuit of relay 634 is then opened at contact 622 and this relay by being energized permits the deenergization of relay 623, so that sequence switch 620 upon reaching position 6 comes to rest in this position. The relay 634 has not been energized again in position 6 of sequence switch 620 since the impulse circuit will have been closed by this time at the sender 418 to cause the energization of relay 625.

The relay 625 now closes a circuit from ground over its armature and front contact, armature and front contact ofrelay 626, contacts 613 (6), right-hand winding and armature and contact of relay 629, contact 614 (6), winding of the units register 740 to battery and ground. In parallel to this circuit, the above described circuit for the left-hand Winding of relay 629 is also closed. The register 740 becomes energized and moves from position O into position 1. In passing from position 0 into position 1, the master contact 745 short circuits therighthand winding of relay 629 causing this relay to become energized. In response to the first interruption of the impulse circuit during the transmission 'of the units series, the relay 625 releases its armature and causes the deenergization of relay 629. At the next closure of the impulse circuit, relay 625 becomes energized and the above traced circuit is closed for the units register 740.

Register 740 inoves from position 1 into po-' sition 2. When the units series has been completed, and the impulse circuit is opened for a comparatively long period on the last impulse, relay 634 attracts its armature and closes the above traced circuit for relay 623. Relay 623 becomes energized and closes a circuit including contact'636 (6) for driving sequence switch 620 out of position 6 and into position 9.

The register comprising the tensand units registers having been positioned in accordance with the designation of the particular line in the even hundred subscribers lines that is desired to be tested, is now operated to control the tens and units selective movements of the final switch to establish a circuit from the testing operators position to the terminals of the desired line. As sequence switch 620 reaches position 9, the fundamental circuit'is closed from battery through the winding of relay 452, contact 471 (3), right-hand armature and front contact of relay 446, contact 478 (3), contact 638 (9) winding of stepping relay 625, contact 639 (9), contact and armature of relay 657 to ground. Relays 452 and 625 are energlzed in this circuit. Relay 452 closes a circuit from ground over its armature and front contact, contact 456 winding'ofv brush tripping position is approached the n. al

interrupter 455 momentarily closes a circuit as follows in shunt of the stepping relay 625 in a fundamental circuit: battery through the winding of relay 452, contact 449 (4) to ground at interrupter 455. At the first closure of the interrupter contact 455, relay 625 is deenergized and closes a circuit from ground over its armature and contact, contact 613 (9), right-hand winding and armature and contact of relay 629, contact 628 (9), contact 732 of register 730, winding of said register to battery and ground. In parallel to this circuit, a circuit is also closed for the left-hand winding of the differential relay 629. The register 730 is energized and moves forward one step from the position to which it :as set by the operatoifs impulse sender 418. The master contact 761 in closing between positions short-circuits th right-hand winding of relay 629 permitting this relay to be energized and to open the driving circuit of the register 730. Said register tl'ierefor advances through only one position where it awaits the deenergization of relay 629. As the brush tripping spindle reaches its tripping position, the interrupter contact- 455 opens and the stepping relay 6:15 is energized. Relay 625 opens the circuit of the left-hand winding of relay 629 permitting this latter relay to release its armature. As the brush tripping spindle approaches the next tripping position, the interrupter contact 455 closes, relay 625 is deenergized and the register 7 is driven forward another position, in the manner described. This operation continues until register 7 30 reaches position 0. As soon thereafter, as relay 625 is again deenergized, a circuit is closed from battery through the winding of sequence switch 620, contact 636 (9), contact 784 (0), contact 628 (9), contact and armatur and righthand winding of relay 629, contact 613 (9), back contact and armature of relay 625 to ground. In parallel to thiscircuit, a circuit is also completed for relay 657. Relay 657 operates to open the fundamental circuit, while sequence switch 620 is energized and moves from position 9 into position 12. The fundamental circuit having been opened at the armature and contact of relay 657, the relay 452 is deenergized as soon as the interrupter contact 455 is again opened, which indicates that the brush tripping spindle is in position to cause the tripping of the proper set of brushes. Relay 452 completes a circuit from ground over its armature and back contact, contact 456 (4), through the winding of sequence switch 450 to battery and ground. Sequence switch 450 moves from position 4, into position 5.

The fundamental circuit is again closed to control the units selective movement of the final switch. Relay 452 by energizing closes a circuit from ground over its armature and front contact, contact 456 (5) though the winding of sequence switch 450 to battery and ground for driving said sequence switch out of position 5 and into position 7. In this position the brush carriage power magnet 461 is energized in a circuit from battery through the winding of said magnet, contact 451 7), front contact and armature of relay to ground. The brush carriage rotates the selected set of

brushes

476, 479 and 470 over the level of terminals containing the terminals of the called line 420. The interrupter 457 closes a circuit for relay 452 including contact 449 in shunt of the stepping relay 625 for each set of terminals passed over by the brushes. At the first closure of the interrupter contact 457, relay 625 is deenergized and completes a circuit from ground over its armature and back contact, contact 616 (12), right-hand winding and armature and contact of relay 629, contact 214 (12), contact 7 42 of the units register 740, winding of said register to battery and ground. In the manner described in connection with the tens register 730,the units register is driven from the position to which it was adjusted by the operators impulse sender to position 0. Upon the next closure of the interrupter contact 457, after the register 740 has reached its 0 position, indicating that the brushes are about to make en gagement with the

terminals

483, 484 and 485 of the desired line, relay 625 is deenergized. A circuit is now closed from battery through the winding of sequence switch 620, contact 636 (12), contact 744 (0), back contact and armature of relay 674, contact 743 (0), contact 614 (12), contact and armature and right-hand winding of relay 629, contact 613 (12), back contact and armature of relay 625 to ground. In parallel to this circuit, a circuit is also closed for relay 657. Relay 657 operates to open the fundamental circuit while sequence switch 620 is energized and advances from position 12 into position 14. As soon as the

brushes

476, 479 and 470 are accurately centered on the terminals of the desired line, the interrupter contact 457 opens and relay 452 is deenergized. A circuit is closed from ground over the armature and back contact of relay 452, contact 456 (7), winding of sequence switch 450 to battery and ground. Sequence switch 450 moves into position 10. The sender sequence switch- 620 on reaching position 14' continues to move into position 16' by means of the following circuit: battery through the winding of sequence switch 620, contact 636 (14), contact 734 (0), contact 628 (14), contact and armature and right-hand winding,

of relay 629,-contact 613 (14), back contact andarmature of .relay 625 to ground. In position 16, the following circuit is closed to drive sequence switch 620 into its normal position 1: battery through the winding of said sequence switch contact 636 (16), contact 744 (0), back contact and armature of relay 674, contact 748 (0), contact 614 (16), contact, armature and right-hand winding of relay 629, contact 613' (16), back contact and armature of relay 625 to ground. The register sender is thus restored to its normal position and may be taken for use to control otherfi'nal selector switches.

If the test-ing operator wishes to" render the subscribers line 420 busy, she depresses the key 405. This key closes a circuit over contact-459 (10), right-hand winding of relay 464', contact 467 (10), brush 470, test terminal 485, Winding of cut-oft'relay 486 to battery and ground. Relay 464 is energized and closes a low resistancepath over its left-hand winding, contact and left-hand armature, winding of relay 462 to key 405 and ground. This low resistance path reduces the potential on, the test terminal 485 to render it busy to other final selector switches. Relay 462 closes a circuit from ground over its armature and contact, winch ing of rela 47 5 to battery and ground. Relay 475 shunts out the

condensers

472 and 473" thus completing a full metallic'circuit from the operators testing equipment to the terminals of the selected line.

it The operator by depressing the key 406, closes a. circuit for relay 475 to complete a full metallic circuit to the selected line with;

out rendering said line busy. In this mah;

n'ei the line relay of the line 420 may be operated from the testing operators position to initiate the operation of a line finder switch toenable the performance of the necessary tests.

i 'It is frequently desired to test the seveial succeeding linesin the same level in the switch. This may be accomplished withoutreleasing the final switch and resetting it onithe terminals of each individual line. After the first linehas been tested the operator depresses a key 408' and also a key 407. I The. closure of key 408 completes, a circuit frombattery. over said key, left hand. winding of relay 411 to ground at the backQcontact and armature of relay 412'. Belay 411 is energized and completes a circuit from ground through its right hand winding, the right-hand winding of relay 412, contact and armature'of relay 411, key 407, contact 471 (10), winding of relay 452 to battery and ground. iRelays- 412 and 452' are energized in: this circuit.

The relay 412 locks up in: a circuit: frorni.

battery over the key 408, left-hand winding, front contactand armature of relay lay 452 to ground: Thebrush carriagebe.

gin's to rotate. Asthe brushes approach, the next set of terminals in the level, inter rupter contact 457 closes a" circuit-from'battery through the winding of relay 452, con-i tact 449 (11): to ground at interrupter con? tact 457. This circuit shunts out therighte hand Winding of relay 4'11 permittingthis, relay to be deeiiergized 'andz-to open the: original energizing circuit of, relay "452.: When, therefore, the brushes center on the next set of line'terminals the interrupter contact 457 opens andfrelayrr452' issdeenergized. Relay 452 opens the-circuit otthe brush carriage power magnet 46:1 and closes a circuit from battery throughfithe winding of the holding"magnet 46.5, coiltact 454 (11), back contact and armaturef of relay 481, back contact and armature/of relay 452 to ground. Magnet 465: operates to arrest the movement ofthe bruslncarriage'. In parallelto this circuit, a circuit is also closed from battery through the winding of relay 482, contact 468 (11) 'back contact and armature ofrelay'452 to ground. Relay 482 which is slow-to-energi'ze at-- tracts its armature afteran interval and closes a circuit for relay 481: to ground; at the back contact and armature: of relay 452. Relay 481 which is also SlOVrtOPQll ergize attracts its armature'after an interval and opens the circuit of the holding magnet 465. When the necessary tests have been performed on the second line of the level. .keys408 and 407 are again depressed causing the energiz at'ion of relay 452, and

the consequent advance of the brush car'- with the relay 474. When relay 474 is energized a circuit is completed as follows for

relays

673 and 674 in position 9 of the sender sequence switch 620: battery through the windings of

relays

674 and 673, contact 640 (9), armature and contact of relay 474 to ground at contact 466 (-l to 8-).

Relays

674 and 673 lock up a circuit from battery through the windings of these relays, contact and armature of relay 673, contact 746 (1 to 9) of the units register 740 to ground at contact 466. When the units register 740 reaches position 9, in the units selection its does not move sequence switch 620 out of position 12 and into position 14 as in the manner described in connection with the selection of a line in the even hundred group. Instead, acircuit is closed as follows to drive register 740 out of position 0; battery through the winding of said register, front contact and armature of relay 674, contact 743 (0), contact 614 (12), contact, armature and right-hand winding of relay 6529, contact 613 (12), back contact and armature of relay 625 to ground. The register 740 therefore runs through an additional cycle causing the brush carriage of the final selector to be driven over the first or even hundred section of terminals and onto the terminals of the desired line in the second or odd hundred section. WVhen the register 740 passes from position 9 to position 0, in its second rotation the locking circuit of relays 674 ando673 is opened and these relays are deenergized. In position 0 of the register 740 the above traced circuit is closed including contact 744 and the back contact and armature of relay 674 for driving sequence switch 620 into position 14.

What is claimed is:

1. In a telephone system, a selective switch, a sender normally conditioned to control the operation of said switch, a plurality of automatic switches, a second sender, means controlled by: said second sender for operating said automatic switches to extend a connection to said selective switch, means controlled by said second sender for operating said selective switch, to further extend said connection, a connecting circuit, means for extending said circuit to said selective switch, and means operative upon the extension of said connecting circuit for rendering said first sender effective to control said selective switch to further extend said connecting circuit.

2. In a telephone system, a selective switch,

a sender normally conditioned to control the operation of said switch, a plurality of automatic "switches, a second sender, means controlled by saidsecond sender for operating said automatic switches to'extend a connecthe selective switch to further extend the connecting circuit.

3.111 a telephone system, a selective switch, a sender normally conditioned to,

control the operation of said switch, a plurality of automatic switches, a second sender, means controlled by said second sender for operating said automatic switches to extend a connection to said selective switch, means controlled by said second sender for operating said selective switch to further extend said connection, said first sender bein inoperative during the control of the selective switch by said second sender, a connecting circuit, means for extending said connecting circuit to the selective switch, means responsive to the extension of the connecting circuit for placing said first sender in condition to control the selective switch, means for setting said first sender, and

means for operating said selective switch in accordance with the setting of such sender to further extend said connecting circuit.

4. In a telephone system, a !selective switch, a sender normally conditioned to control the operation of said switch, a plurality of automatic switches, a second sender, means controlled by said second sender for operating said automatic switches to extend a connection to said selective switch, means controlled by said second sender for operat ing the selective switch to further extend said' connection, an operators position, a connecting circuit thereat, means for extending said connecting circuit to the selective switch, and means operative upon the extension of said connecting circuit for rendering said first sender effective to control the selective switch to further extend said connecting circuit.

5. In a telephone system, a selective switch, a sender normally conditioned to control the operation of said switch, a plurality of automatic swtches, a second sender, means controlled by said second sender for operat ing said automatic switches to extenda connection to said selective switch, means controlled by said second sender for operating the selective switch to further extend said connection, an operators position, a COD. necting circuit thereat, means for extending said connecting circuit to said selective switch, means responsive to the extension of the connecting circuit for placing said first sender in condition to control said selective switch, means. at the operators position for setting said first sender, and means for opcrating said selective switch in accordance with the setting of such sender to further extend said connecting circuit.

6. In a telephone system, a selective switch, a trunk leading to said switch, a sender normally conditioned to control the operation of said switch, means for extending a connection over said trunk to said selective switch, a second sender, means controlled by said second sender for operating said selective switch to further extend said connection, a connecting circuit, means for extending said connecting circuit over said trunk to said selective switch, and means responsive to the extension of said connecting circuit for rendering said first sender efiective to control said selective switch to further extend said connecting circuit.

7. In a telephone system, a selective switch, a trunk leading to said switch, a sender normally conditioned to control the operation of said switch, means for extending a connection over said trunk to the selective switch, a second sender, means controlled by said second sender for operating the selective switch to further extend said connection, said first sender being inoperative during the control of said selective switch by said second sender, a connecting circuit, means for extending said connecting circuit over said trunk to the selective switch, means responsive to the extension of the connecting circuit for placing said first sender in condition to control said selective switch, means for setting said first sender, and means dependent upon the setting of such sender for operating said selective switch to further extend said connecting circuit.

8. In a telephone system, a selective switch, a trunk leading to said switch, a sender normally conditioned to control the operation of said switch, means for extending a connection over said trunk to the selective switch, a second sender, means controlled by said second sender for operating the selective switch to further extend said connection, said first sender being inoperative during the control of said selective switch by said second sender, an operators position, a connecting circuit thereat, manual means for extendlng said connecting circuit over said trunk to said selective switch, means responsive to the extension of said connecting circuit for placing said first sender in condition to control said selective switch, means at the operators position for setting said first sender, and means dependent upon the setting of such sender for operating the selective switch to further extend said connecting circuit.

9. In a telephone system, a selective switch, a sender normally conditioned to control the operation of said switch, a plurality of automatic switches, a second sender, means controlled by said second sender for operating said automatic switches to extend a connection to said selective switch, means controlled by said second sender for operating said selective switch to further extend said connection, a connecting circuit, means for extending said circuit to the selective switch, and means operated upon the extension of said connecting circuit for rendering said first sender effective to control said selective switch to further extend said connecting circuit.

10. In a telephone system, a selective switch, a sender normally conditioned to control the operation of said switch, a plurality of automatic switches, a second sender, means controlled by said second sender for operating said automatic switches to extend a connection to said selective switch, means controlled by said second sender for operating said selective switch to further extend said connection, said first sender being inoperative during the control of the selective switch by said second sender, a connecting circuit, means for extending said circuit to the selective switch, and means responsive tov the extension of said connecting circuit for placing said first sender in condition to control the selective switch to further extend the connecting circuit.

In witness whereof, I hereunto subscribe my name this 29th day of November A. 1)., 1919.

LIPA POLINKOVVSKY.