US1128777A - Telephone system. - Google Patents

Description

C- E. HAGUE. TELEPHONE $YSTEM. APPLICATION FILED APR. 22, 1 910,

3 SHEETS-SHEET 1.

Patented Feb; 16, 1915.

v "0.1:. HAGUE.

TELEPHONE SYSTEM.

APPLICATION FILED APR. 22, 1910.

Patented Feb. 16,1915.

3 snnsTs snmT 2.

/MW y 6 In venfm- C. E. HAGUE.

TELEPHONE SYSTEM.

APPLICATION FILED APR. 22, 1910.

v Patented Feb. 16, 1915.

- a HEETS-SHEET 3.

Efz tar/E5 5 HM Er Um m r CHARLES E. HAGUE, or ROCHESTER, NEW' YORK, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO WESTERN ELECTRIC COMPANY, 'OF ,CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Application filed April 22, 1910. Serial No. 556,924.

To all whom it may concern:

Be it known that 1, CHARLES E. HAGUE, a citizen of the United States, residing in Rochester, county of Monroe, and State of New York, have invented certain new and useful. Improvements in Telephone Systems, of which the following is a specification.

My invention relates to telephone systems 1 0 and more particularly to telephonesystems of the class lmown as calledistributing systems. In systems of thischaracter means is provided whereby an incoming call may be handled manually by the first operator in the exchange, who is not busy attending to another call.- In this manner the number of required operators is reduced, since the calls may be so distributed that each 0 erator is kept working to her maximum e ciency at all times.

My invention relates to trouble indicating features of the line switch circuit, to the intermediate switch circuit, and also to the cord circuit arrangement for use with this system and toxthe means provided therein whereby only two calls may be received by a single operator simultaneously.

' The system here illustrated is such asystem as would be used in a large telephone v exchange wherein it is desirable to interconnect a number of telephone lines exceeding twenty-five hundred. In generaltherefore I provide a line switch for each 'line.capable of selecting any one of a number Of'1I1l36I mediate switches,-these intermediate switches being capable of selecting any one of a large number of cord circuits.

' My invention furthericonsists in the improvements in electrical connections and apparatus wherebyan economic and efficient combination resulting in an operative comtem is produced, and in the further'det'ails and combinations described in the specification and specifically claimed.

My invention is illustrated in the accompan'ying drawing'consisting of a'single" system distributed for convenience upon thfpee sheets. D

Figure 1 is an. illustratlon of telephone line and the line S ct itch, Fig. 2 is an illustration- Specification of Letters Patent. Y

Patented Feb. 16, 119-15.

I selector switch and Fig. 3 is an illustration of the cord or connecting circuit and the telephone line to be called.

My invention, as here illustrated, is shown applled to a two wire common battery system, by which is meant that the system operates with only two wires between the exchange and the subscribers instrument, a

third wire orground being unnecessary between the subscribers instrument and the 4 central office, and that a single source of direct current located at the central oflice sufiices for supplying energy for both signaling and talking purposes.

Referring to Fig. 1, the calling subscribers station 1 is provided with the usual annunciator 2 and condenser 3 connected in a bridge between the limbs 45 and 5 of the telephone line, and with the transmitter 6 and receiver 7 adapted tobe placed in a bridge between the limbs of the line by the actuation of the switch-hook 8. At the cen tral oiiice line conductor 4 extends through the normal contacts 9 and- 10 of cut-off relay 11 and through the coil 12 of line relay 13 to the battery wire 14 which is shown contrated on Fig. 3. The line conductor 5 extends, at the central office, through normal contacts 15 and 16 of cut-off relay 1.1 and thence through the coil 17 of relay 18 to the ground pole of battery A. Cut-off relay 11 is also provided with normally open contacts 20 and 21 adapted, when the relay is actuated, to extend the limbs 4 and 5 of theline to the lever contacts 22 and 23 of relay 18, the lever 22 of relay 18 being connected through the' normal contact 24 and conductor 25 through the coil 48 of cut-off relay 11 to ground. Relay 11 also has the coil'27, v one terminal'of which is connected with the inon battery telephone call-distributing syslive pole of battery A and the other terminal This contact 30 is adapted when actuated .to connect with contact 31 which extends to the lever 32 of relay,.18 and thence through the normal contact 33 to the lever '34 of line the-calling;

relay 13, this lever; being normally connected through itscontact35 Withconductor 26. Contact 37 of the set of contacts of cut-oil 3' relay illustrated as make before break contactsextends to normally open contact 38 of'line reIayF-B, the lever 39 of that relay being connected'through conductor 40 and the. coil of the line switch motor-magnet 41 through the interrupter 42 to the battery wire 14.The"contact lever 32 of relay 18 also connectswith the contact 44 of relay 13,v

the normally open contact 45 of that relay being connected through the winding 46 of said relay, conductor 47' and the coil 48 of relay 11 with earth. Line relay 13.also has the normally open contact 65 adapted to connectthe lever 34 With-earth when the relay is actuated.

The multiple jacks 50 have their. sleeve contacts 51 connected to the inside contact a of cut-ofi' relay 1]. and their tip contacts 52 connected to the inside contact 210f cutoil relay 11.

Relay 18 has the normally open contacts 53 and%5 4 adapted, when the relay 18 is actuated, t Qextend the line conductors 4 and 5 through conductors 55 and 56 to the collector segments 57 and 58 of the line switch 60. Relay 18 also has the normally-open 'contact'61 adapted, upon the actuation of the relay, to connect the lever 32 through conductor 63 with the third or private collector segment 64 of the line switch 60..

Line switch 60, which is here shown only conventionally comprises the circle of insulated contacts held betweerf insulating rings 67 by the clamping screws 68, and the three segments 57, 58 and 64 electrically separated and mounted so that the'brushes 69, 70 and 71 will close the electric circuits between these segments and three contacts infthecircle for each of the various rotary positions of the brush spider.

A further description of this switch will appear later inthe specification.

In the illustratedposition. the talking strand 55 is shown connected by brush 69 through segment .57 and contact 73-with conductor 74. Talking conductor 56 .is shown connected by means of-the brush 70 through segment 58 and contact 75 to conductor 76, and conductor-63 isshown connected by means of brush 71 through segment 64 and contact 77 to conductor 78,-

this latter conductor being known as the private conductor as distinguished from the talking circuit. Conductors 74, 76 and 78 continue to Fig. 2 where they, bear the same numerals.

In Fig. 2 conductor 74 is normally connected through contacts 80 and 81 ofcutoff relay 82 and the coil of relay 83 to the battery conductor 14, and conductor 76 is normally connected through contacts 84 and 85 of cut-ofi' relay 82 to earth. The relay 83 is provided with normally open contacts 86 and 87, contact 86 extending through conductor 88 and the coil of the vertical motorand private conductor 104.

magnet 89 and interrupter 90 to the bat tery conductor 14, and the contact 87 extendingthrough conductors 91 and 92", the

normally closed rotary oif- normal contacts 93 and 94, conductor 95, the vertical wiper 96 and the lower vertical contact 97 to earth. The.relay 83 is 'also"'provided with the lever contact 98, normal contact 99 and open contact 100, the lever 98 being connected through conductor 101 with the rotary private wiper 102, which in. turn conv nects during the actuated condition of the intermediate switch with. rotary contact 103 he normally closed contact 99 connects through conductor 105 and the coil 106 of relay 82 with the normally openinside contact 107 of that relay. The normally open contact 100 of relay 83 is connected through conductor 108 with the normally open contact 109 of.

. mal contacts 119 and 120 of relay 83 and conductor 121 to the normally open contact 122 of the vertical off-normal springs, this same spring being'also connected through the coil 123 of relay 82 with the normally open contact 124 of relay-110, the other open contact 125 of this relay being joined with contact 111. Contact 122 of the vertical ofinormal springs is also connected through conductor 127, contacts 128 and 129 of. the rotary off-normal springs and conductor 130 to the lever contact 98:0f relay 83. 'One of the vertical ofl"-normal contacts 132 is connected with earth and the third contact 133 is connected with theprivate conductor 78,

these three contacts being normally separatedand being bunched when the switch is in its actuated condition. The normally open contacts 134 and 135 ofacut-ofi' relay 82 are adapted'to extend the talking conductors 74 and 76 through conductors 136 and 137 to the wipers 138 and 139, these wipers being connected during conversation through contacts 140 and 141 with the talking conductors 142' and 143 which extend to talking conductors bearing the same numerals on Fig. 3 of the .drawing.

In Fig. 3 the talking conductors 142 and 143 are shown extending through condensers 144 and 145 and contacts 146 and 147 and 191 and 192, 148 and 149 of the operators listening and ringing keys to the sleeve 150 and tip 151 respectively of the calling plug. The relays '153 and, 154 have their coils connected in a bridge between the talking conductors 143 and 142, this bridge containing the main battery A. Relays 164- and 165 likewise have their coils connected in a similar bridge of the talking circuit on the calling side of condensers 1 14 and 1 15. Relay 153 has the normally open contacts 155 and l56,-the contact 155 being connected with earth and the contact 156 being connected ed contact 162 of relay 153 is adapted-to connect with the lever 158 of that relay when the relay is actuated. Relay 154 has a lever contact 166 connected through conductor 167 with oneterminal of the call lamp 168,;the other terminal of this lamp being connected with the live pole of bat-- tery A. The lever 166 of relay 154 is normally connected with contact 169 and thence through conductor 170 to the normally open contact 171 of relay 165 and also through the normally closed contacts 172 and 173 of relay 16+ to one terminal of the calling supervisory lamp 174, the other terminal of this lamp being connected with the live pole of battery A. The relay 151 has the normally open contact 175 which is connected through conductor 176 with the normally closed contact 177 of relay 165, the lever 178 of relay 165 being connected with earth. The contact 157 of relay153- is also connected through conductor 180 with the lever .contact 181. of relay 165, this contact being normally connected throu h contact 182 with the conductor 183 wlnch conductor is connected by means of the branch wires 18 1 to similar contacts 182, associated with one half of the other cord circilitsappearing in the same o|')erator s position as the cord circuit here illustrated, and it is to be understood that these other cord circuits are theoretically represented by the branch wires 181- to such an extent that they may be .claimed in the appended claims of this specification. Contact 181 of relay 165 is adapted to connect with contact 185 when the re lay is actuated, the latter contact being connected with earth.

The operators listening key 190 has the contacts 191 and 192 normally completing the tip strand ofthe talking circuit and has the contacts 19; and 19+ and 195 adapted when the key is actuated to place the operators receiver 196, secondary 197 of induction coil 198 and condenser 199 in a bridge between the talking conductors. The operators listening key 190 also has the auxiliary contacts 200 and 201 adapted upon the actuation of the key to connect the tip of the calling plug through. the tertiary winding 203 of the operators induction coil 198 to' earth. The primary winding 201 of this induction coil is connected in series with the operators transmitter 205 and any suitable source of current not shown in the drawing. The relay 165has the normally open contacts 207 and 208 adapted when actuated to close a shunt about contacts 191and 192 of the operators listening key 190.

The operators ringing key 210 has the normally open contacts 211 and 212, the contact 211 being connected through the ringing generator 213 to earth and the contact 212 being connected through the noninductive resistance 214' to battery conductor 1 1.

The called telephone line 1 illustrated at the right of Fig. 3 is equipped with apparatus identical with the apparatus illustrated and described in connection with the calling telephone line 1, thecorresponding' apparatus of the called telephone line being designated by like figures with the sullix itbcing understood that the complete apparatus oi the called telephone line, part of which is omitted from this drawing for the sake of (:learness, is so theoretically illnstrated that it may be claimed in the appending claims.

The conventionaldrawing oi the inter mediate switch shown on Fig. 2 is intended to illustrate any form oi? connecting apparatus to which the other features of my invention may be applied. This switch. comprises the vertical shal t 220 carrying the private and talking wipers 102, 138 and 139 in insulated relation to the shaft and to one another, but so secured to the shaft that they move therewith as a unit. Also secured to this shaft is the vertical cylindrical ratchet by means of which the vertical motor-magnet 89 is adapted to step the shaft 220 and all parts integral therewith vertically. This ratchet cylinder is also engaged by the prong 221 of double-dog 222'which dog is adapted to be attracted by the release mag net 117 for permitting the shaft 220 to return to its normal position. Upon the upper end of this shaft the ratchet wheel 223 is mounted and is so keyed to the shaft that the shaft can slide up and down through the ratchet whcel but that the-shaft and ratchet wheel are caused to rotate as a unit. This ratchet wheel is adapted to be engaged by the pawl 224 which is adapted to be actuated by the rotary minor-magnet 112, this pawl as wellns the pawl of the vertical magnet being normally held out of engageanent with the ratchet teeth by means of 'I raise this spring and maintain the contacts 93 and 94 and contacts 128 and 129 in closed condition. 1

On the lower end of the shaft 220 the insulating collar 230 is so mounted that theshaft may readily rotate therein, but that the collar is caused to move up and down with the shaft as a unit. This collar carries the vertical wiper 96 which is double the same as private Wiper 102, the other half, notshown because it is concealed by the part here illustrated, rubbing .lightly against the back of the bank. of vertical contacts 231, these two brushes and their contact with the bank 231 acting as a guide to prevent the collar 230 rotating with the shaft.

- The lower contact 97 of the set 231 is con-- nected to ground, the second contact of the group is connected to the armature ofrelay contact. 240 is adapted toconnect'through ntact 243 and non-inductive resistance 244 -,.-,with ;battery conductor 14. The upper ternflii-nal' of the non-inductive resistance 244 is connected with the contacts 243 of-the nine I other cord circuits'to which conductor 239 is'connected. This particular group of ten cordcircuits are connected to the various contacts of the intermediate selector switch which comprise the fourth row of con- In the operation ofmy system the subscriber in charge of substation 1 removes the receiver 7 from the switch hook 8 and thereby :icloses an electric circuit from the live pole ofbattery A through conductor 14, the

coil112 of relay 13, contacts 10 and 90f relay 11," line conductor. 4,.transmitter 6, receiver 7, switch-hook 8, line conductor 5,

contacts 15 and 16 of cut-off relay 11 and thef'coil 17 of relay 18 to earth. Thebur- "rent in this path actuates relays 13 and-18 completing the circuit from the battery A through. conductor 14, interrupter 42, motor-magnet 41, conductor 40, contacts 39 and 38 of' relay 13, contacts 37 and 31 of relay 11, contacts'32 and 61 of relay 18, conduc-.

tor. 63, contact segment 64, brush 71 and the various busy or grounded contacts of the line'switch. The interrupter current in this path steps the line switch from one position to another until the rivate brush 71 arrives at a contact such as '77 which is not grounded. Instantly the current through the in-.

masmz'z terrupter 42 and the motbi-mgna 41 takes a new pathover conductor 40, contacts 39 and 38 0f relay 13, contacts 37 and 31 of cut-ofi' relay 11, contacts 44and 45and coil and immediately closes a locking circuit for relays 11,-18'and .13, this circuit'extending from the battery conductor 14' through the coil 27 of relay 11, conductor 26, coil 28 of relay 18, conductor 29, contacts 30 and 31 of. the now actuated cut-ofi' relay 11, contacts 44 and 45' and coil 46 of relay 13, conductor 47 and the coil 48 -of relay 11; In this manner the'three relays associated with the line are held in their actuated positions and line conductor- 4 is extended through contacts 9 and 20 of the cut-oft relay 11, contacts 22 and 53 of relay 18, conductor 55, segment 57, brush 69 and contact 73 to the talking conductor 74 which extends to Fig.

tor 56, segment 58, brush 70 andcontact 75 to the talkihg conductor 76 which extends to Fig. 2.-. If the line switch had been noriiially standing on idle contacts the cut-cit relay would have been actuated over' this same path without the line switch moving from its initial position- Referring now to Fig. 2, the line circuit of Fig. 1 being still' closed at the-substation a circuit is completed from the live pole of battery through conductor 14, the coil of relay 83, normal contacts 81 and 80 of relay 82, talking conductor 74 and the path formerly traced through the line cirto I ioa

conductor 88, contacts 86 and 87 of relay 83, conductor 91, conductor 92, the now closed contacts 93 and 94 of'the rotary olfnormal springs, conductor 95, the vertical wiper 96 and grounded contact 97 of the vertical bank 231. The current in this path relay 13 to become deenergized, but the relays 1'1 and 18 now remain energized b current from battery through their coils 2 and 28, conductor 29, contacts 30 and 31 of relay 11, contacts 32 and 61 of relay 18 to earth as formerly described through the contacts 133 and 132 of the vertical off-normal set of springs .in Fig. 2. .The relays.

235, 236- and 237 being shown in their actuated positions, the three succeeding contacts above the grounded contact .97 in the vertical bank 231 are also grounded and therefore the vertical motor-magnet 89 will continue to receive impulses through the inter rupter 90 until the shaft 220 has been stepped up sufficiently that the vertical wiper 96 steps off of the last grounded contact which extends to relay 237 onto the ungrounded contact which extends to relay 238. When this occurs the current through the interrupter 90 will follow a' new path extending through the coil of motor-magnet 89, conductor 88, contacts 86 and 87 of relay 83 and the .coil of relay 110 to ground. This relay is of high resistance compared with the resistance of the motor-magnet 89 so that the relay will be actuated but the motor-magnet will not operate to raise the shaft 220.

Upon the actuation of relay 110 a path for current is established from the-live pole of battery A through interrupter 90, the coil of the rotary motor-magnet 112, con

tactstlll and 109 of the relay 110, conductor Y condition shown in the drawing and therefore interrupting the circuit through the motor-magnet 112 at the now interrupted contacts 128 and 129 ofthe rotary off-normal set of springs.

The first rotary step of the. shaft 220 brings the private wipers 102 into contact with the-first rotary set of private contacts 103, this set of contacts extendingto the cord circuit which, as will be later shown,

.if busy, maintains aground 'on its private wire, which extends to the various contacts 103. Therefore assuming the first few contacts 103 to have been busy and therefore sis grounded, current will flow from the live pole of battery A through the interrupter. 90, coil 112 of the rotary motor-magnet, contacts 111 and 109 of relay 110, conductor 108, contacts 100 and 98 of relay 83, conductor 101,'wiper.102 the busy. contacts 103 to ground. The shaft 220 will therefore be moved step by step in a rotary direction until wipers 102 step off the last busy contact 103 onto an idle and therefore not grounded contact. When this occurs a new path for current is taken through the interrupter 90, coil of rotary motor-magnet 11.2, contacts 125 and 124 of relay 110, coil 123 of relay 82, conductor 121 and contacts 122 and 132 of the vertical off-normal set of springs to ground. The coil 123 of relay 82 being of much higher resistance than the coil of motor-magnet 112, the relay 82 is actuated, but the shaft 220 is not given a further rotary step.

Upon the actuation of relay 82 the circuit of relay- 83 is interrupted at contacts 80 and 81 of relay 82 and the circuit of relay 110 is in turn interrupted at contacts 86 and 87 of relay 83. A locking circuit is therefore immediately established through the coil 106 of relay 82, this circuit being traced as follows: from battery Wire 14 and through the coil of release magnet 117 which magnet is of low resistance and is not actuated in series with the coil 100 of relay 82,

conductor 110, contacts 115 and 107" and coil 106 of relay 82, the now closed contacts 99 and 98 of relay 83, conductor 101, privatewiper 102, private contact 103, conductor 101, contacts 159 of key 160 (Fig. 3) and contacts 158 and 102 of relay 153 to earth, the relaybeing now actuated as will be explained later..

If, after the shaft 220 has commenced its rotary motion and the wipers 1.02, 138 and 139 have started across some particular row of contacts, all the contacts in this row become busy, then the shaft 220 will continue its rotary motion until the wipers 102 arrive at the last of the rotary contacts.

This last contact is an extra or unused contact and therefore when the wipers 102 ,arrive at this position, relay 82 will be actuated as above described, but its locking circuit will not be closed through coil 106, since no ground will come upon the wipers 102,

Relay 106 will therefore immediately fall .back to its normal position whereupon the circuit of the release magnet 117 will be.

completed from the battery wire 14 through the coil of the magnet, conductor 116, contacts and 118 of relay 82, contacts 119 and 120 of relay 83, conductor 1.21 and' contacts 122 and 132. of the vertical oil'- normal set of springs to ground. This causes the shaft 220 and the wipers carried thereon to return to their normal position, or at least to return to the normal position so far -as the rotary motion is concerned. The relay 83 will however be again actuated so thatby the time the shaft has rotated back to its original position of rotation,the vertical magnet will again be actuated and will now step the. switch up to the position opposite the next row of contacts and an idle trunk will then be selected in the next row. In this manner only a very slight delay is caused by the trunk becoming busy after. the switch has started on its rotary motion.

Returning to Fig. 2 the actuation of relay 82 extends the line circuit from conductor 74 through contacts 80 and 134', conductor 136, wiper 138, contact 140, conductor 142 and the coil of relay 154 (Fig. 3) to the live pole of battery A and extends conductor 76 through contacts 84 and'135 of relay 82,

conductor 137, wiper 139, contact 141, con

ductor 143 and the coil of relay 153 (Fig. 3) to the ground pole of battery A. The current in this path actuated relays 153 and 154. The actuation of relay 153 connects the private conductor 104 with earth as has previously been explained and also connects the earth side of battery through contacts 155 and 156, conductor18O and contacts 181' and -182 through conductor 183 to the branch.

point 184 which is common to one half of the cord circuits appearing at this particular operators position. This, as will be seen,

grounds one half of the private conductors 104 leading. to this particular operators position as long as sleeve relay remains unactuated. When this relay 1s actuated however the grounds are removed from all of the other cord circuits so that this 0per-.

all of the other nine cord circuits leading to the particular horizontal row of contacts in the intermediate switch to which the illustrated cord circuit leads. Itwill be seen that the common conductor 239 is normally' grounded through contacts 240 and 2410f 1O relays 154' in ten'difi'erent cord circuits and the contacts 242- of the keys 160. It will therefore require the actuation of all of these ten relays 154 to remove this shunt about the coil of relay 238. Upon the removal ofthis shunt the current will pass through the coil of re y 238 and act.

atethat relay to ground another contact in the bank 231. -The act1'1ation of relay. 154 also completes the circuit of the call lamp 168 from the live pole ofbattery A through the lamp, conductor 167, contacts 166 and 175- of relay- 1'54, conductor 176 and contacts 171 and 178' of relay 165 to ground. The

display of the signal 168 indicates the operator that a calling subscriber has been automatically connected with this particular cord circuit with which the lamp 168 is associated and the operator therefore throws of earth and a current will therefore flow from the sleeve of the tested jack through tip 151 of the calling plug, contacts 149 and 148 of the operators ringing key 210, the

, now closed auxiliary contacts 201 and 200 of the operators listening key 190 and the tertiary winding 203 of the operators induction coil to ground. Current in this path will cause an inductive disturbance in the secondary 197 of the operators induction coil which will be heard in the operators receiver 196. If however the desired line is found to be idle, the'operator inserts her calling plug completely into the jack of the desired line, thus causing the tip and sleeve contacts 151 and 150 of the plug to electrically register with the tip and sleeve contacts 52 and 51' of the jack. The operator now actuates her ringing key 210-which connects the live pole of battery A through conductor 14-, non-inductive resistance 214, contacts 212 and 147 of the ringing key 210, sleeve contacts'150 and 51' of the plug and jack, contacts 22' and-'24 of relay 18, conductor 25 and the coil 48 of cut-off relay 11' to ground. The current in this pathactuates cut-'ofi relay 11 moving its contacts i 9. and 15 into their abnormal positions and connecting the tip' and sleeve contacts 51 and 52 of the jack directly with the limbs 4. and 5' ofthe desired telephoneline. At the same time the actuation of the ringing key 210 completes a circuit for the ringing generator 213- through contacts 211 and 149' of rin g key 210, the tip contacts 151 and 52 o the plug and jack, contacts 21' and 15' of cut-ofl:' relay 11, line conductor 5,-

annunciator 2', condenser-'3", line conductor sleeve contacts'51 and 150 of the .jack and plug, contacts 147- and'212 of ringing key I 210 and the non-inductive resista'nce214 to b attery and back to the other pole of the rmging generator. The current 1n this path being alternating or pulsating passes 44, contacts 9- and,20" of cut-off relay 11',

through the condenser 3' at the subscribers station and soundsthe annunciator 2", calling the subscriber to his telephone. The operator now releases her ringing key and thereupon complctesa path for current from the live pole of battery A through the coil of relay 165, contacts H6 and 147 of ringing key 210, sleeve contacts 150 and 51 of the plug and jack, contacts 22 and 2:1 of relay 18, eo1uluctor 25 and the coil 48 of cut oil relay 11 to ground, thusmaintaining the actuation of cut-oil. relay 11 and actuating supervisory relay 165; The actuation of relay. 165 se\ers its contacts 177 and 178 and closes contacts 178' and 171. This severs the circuit of the call lamp 1.68 ell'acing that signal, and completes a circuit "for the calling supervisory signal 174'froin the live pole of battery Athrough the signal, contacts 173 and 172 of relay 16-11 and. the contacts 171 and 178-0f relay 165 to ground. The -actuation of relay 165 also severs contacts 181 and 182, thus removing the ground connection from conductor 183 and therefore from the branch point'184 which frees the ground connection from one half the private wires extending to this particular op erators position.' At the same time the contact 181. otflrelay 165 is grounded through contact 185 of that relay so that thecalling subscriber may now signal the operator without removing the ground connection from the private wire 101 which-controls the release of the intermediate switch.

contacts 191 and 192 of the operators listening key 190.

When the called subscriber responds. to

21 of cut ofl relay 1 1, tip contacts. 52--and'" 151 of the jack and plug, contacts 119 and 118 of the ringing\key 210, series contacts 192 and 191- of the operators listening key 190 in parallel with contacts 207 and 208 of relay 165 and the coil of relay 164 to the ground pole of battery. A. v The current in this path maintains the actuation of relay 165 and actuates relay 161, the actuation of relay 161 severing the circuit of the calling supervisory lamp 174 and indicating to the operator that the called subscriber has answered his call. The calling and called parties are now in conversation and the apparatus heretofore described remains in the proper position to. maintain an uninterrupted conversational circuit between the two subscribers stations so long as the telephone lines are maintained closed at the subscribers" stations. When the conversation has been terminated and the subscribers return their'receivers to their switch-hooks,

The actuation of relay 165 also closes contacts 208 and 207 which complete a shuntabout relay 82, contactsllfiand 120 of relay 83,

conductor 121 and contacts 122 and 132of" 166 and 169 of relay 154, conductor 176 and contacts 171-and 178 of relay 165 to ground. These signals'now act as disconnect signals and indicate to the operator that both the calling and called subscribers have replaced their-receivers upontheir respective switchso hooksf I Upon receipt of the double disconnect signal the operator removes her calling plug from the jack with. which it has been connectedgduring conversation and thereby interrupts the circuit through the winding of relay 165 and the cut-oil? relay l lLarlVhen the contact 181 of 1'elay 165 moves away from its ground connectio'nwith contact 185, the circuit is interrupted from battery (Fig. 2) through the disconnect magnet 117, conductor 116, contacts 115 and 107 and coil 1.06

of relay 82, conductor 105, contacts 99 and.

98 of relay 83, conductor 10l, vviper"102,

contact 103, private conductor 104:, contacts. 159 of the operators busy key..(Fi-gi'3), con

tacts 158 and 157 of relay 153, conductor 180 to the now open contacts 181 and 185 of relay 165. The severing of this circuit releases the relay. 82--(Fig. 2) allowing that relay to resume its normal position and close a low resistance path for battery from conductor 14 through .the disconnect. magnet 117, conductor 116, contacts 115 and 118 of the vertical ofi-normal set of sp rings to ground. The current in this path actuates the release magnet .117 returning the shaft I 220 to its normal condition both as to its rotary and vertical displacement.

When this shaft returns to its normal position the vertical off-normal springs 122, 132 and 133 are-mechanically opened by the Weight of the shaft, thus severing the circuit through the release magnet, and allowing all of the apparatus associated with the intermediate switch to resume its normal and unactuated condition. The interruption of the circuit through the vertical oft-normal springs 133 and. 132 interrupts the circuit from the battery wire 14.- (Fig. 1) through the coil 27 of -cut-ofi' relay 11, the coil28 of relay 18, conductor 29, contacts 30 and 31 of cut-off relay [1. contacts 32 and 61 of relay 18, conductor 12 5 I 63, segment 64-, brush 71, contact 77 and private conductor 78 which extends to the con; tact 133 ofthe vertical. off-normal set of springs. The interruption of the circuit in this pa h releases the relays 11 and 18 a1- 1'80 lowing'them to return to their normal posi. tions, the'line switch 60 however remaining in the position in which it stood during con-.

I versation. The apparatus has thus all reline by hanging up his receiver, as, for example, when a fire or police call is given, or when a malicious call is given and his desired to trace the connection to determine upon what line the call originated. In cases 160, which places a permanent ground upon 'the private conductor 104, extending from the cord circuit to the intermediate switch. This prevents the release of the intermediate switch and therefore holds a permanent ground upon private conductor 78. Thus a circuit is maintained throlgh the winding 27 of relay llpcond'uctor 26, the winding 28 of relay 18, conductor 29, contacts and 31 of relay 11 and contacts 32 and 61- of relay 18 to the private conductor 63 which -1s now grounded. The operation of the switch-hook at the calling subscribers sta- .tion therefore has no effect upon the line relays and the attendant may trace the call and -determin e' the line which is connected with the particular cord circuit upon which the key 160 has been depremed.

Another feature of the line, switch, which i forms no part of my present invention, but

which I-will here explain, is the means'by which thewip ers 69, and 71 are permitted torotate continuously in one direction without having any normal position. and with'-. out the danger of connecting the direct ground, which is associated with'theprivate ing some other conversational circuit.

willbenoted that the segment' 64, which the private segment, is of such length that it-"stands opposite two moreicontacts than portion of the bank of this switch, with contacts of the other portions offthe bank of this switch. which may at the time of the rotation of the switch be in usein completeither of the talking'segments .57 or 58: It

will also be notedthat thefirst and last contacts which are opposite the private segment 6'4 arepermanently grounded. When,

in the rotation of the spider of'this switch, the brush 71 arrives upon the last of the private contacts 247 or that which is permanently grounded, the brush 70 will be stands ing-upon contact'245 which latter contact is entirely free from electrical connections.

71 upon the contact 246which istlikewis'e afree contact, andat the same time places the wiper 70 upon the first of the contacts of the private bank which contact is also per- .withthese disabled lines.

manently grounded. this way the current for maintaining the rotation of the spider can flow first from segment 64 through the brush 71 and contact 247 to groimd then through segment 64, the brush 70 and contact 248 to ground without there being any possibility of a grounded brush coming incontact with either segment 57 or 58 and thus no disagreeable click will be central oiiice when a line becomes accidenof this kind the operator depresses her key tally grounded at some point either .Within or without the central oflice. In systems of this character-heretofore, when the battery limb of the telephone line. outside the exchage became accidentally grounded, the

' line selecting apparatus would be operated to select an idle trunk circuit and thus to extend the disordered line through circuits or apparatus'not individual to the line. .In this manner the trunk circuit would become several lines disabled simultaneously it was possible to use up all of the available. trunks By the present system when a ground occurs upon the line conductor 4 current ,flows from the main battery through conductor 14, coil 12 of line relay 13, contacts -10 and 9 of cut-ofi relay 11 and line conductor 4 to earth. This "actuates relay 13 and-closes a circuit from battery 14 through interrupter 42,'the coil of motor-magnet 41, conductor 40, the now' actuated contacts 39 and 38 of line relay 13,

the closed contacts 37 and 31 of cut-01f relay 11, contacts 32 and 33 ofrelay 18 and the now closed contacts 34 and 65 of relay 13 to ground. Thus the line switch 60 is maintained in its regressing condition independently of th contacts and this switch wi therefore continue to rotate until theattendant hearing the sound 1 of the continuously moving switch either corrects the trouble on the tied up and. useless and in case there were e grounds u on its private line or interrupts the circuit by removing tempting to make a call; The rotation will continue during the time the receiver is off the hook at the'substationand the attendant willtherefore have an opportunity of determining that there is trouble on this- -'particul'ar line without'the subscriber hav- -Thenext step of the spider places the wiper into notify the attendant.

.By having thus described my invention with respect to. the accompanying illustration I do not wish to be understood to have 25 operato for estaliishing a connection between a call-' limited my invention to this particular'embodiment, it being understood that many features of my invention are applicable to many other forms of specific apparatus. It

is to be further understood that many changes may be made in the specific means of accomplishing the results herein set forth without departing from ithe spirit or scope of my invention.

What I claim is-- i 1. A telephone exchange system compris- King a plurality of telephone lines, a P

automatic switching- "ity of link circuits,

means for completing the connection bei tween a calling line and an, idle link circuit, a callv signal associated with the link circuiti to indicate that calling line has been automatically connected therewith and meanspermitting only two call signals being dlsplayed before an operator simulwitha lurality of telephone'lines, of a plurality f link circuits in charge of a single automatic switching mechanismtaneo s y. I i 4 Q/IdEpa telephone system, the combination ing line and an idle one of said link circuits,-an 'ndicator displayed when acalling line is connected with an idle link circuit,

and means to prevent any other indicator being displayed in this particular operators position when two of said indicators are simultaneously displayed. w

3. In a telephone exchangesystem, the

85 combination with a plurality of telephone lines, of a'plurality of link circuits under-- the control of a single operator, switching mechanism for connecting a calling line with an idle link circuit, private conductors 40 extending from the link circuits totheswitching mechanism by which the idle or busy condition of'the link circuit is automatically testedand means to cause all of the private conductors, extending toa particular operators position, to test busy whenever two unanswere d calls are simul taneously recewed at thls. operators pos1-.

' tion.

4-. In a telephone system, the combination with aplurality of telephone'lines, of

a plurality of link circuits at a single operators position, automatic switching. mech- 1 anism adapted to connect a calling line with an idle link circuit, a conductor for each' link circuit over which the busyor idle 'condition of the link circuit is automatically tested by the automatic switching mechanism, the said link circuits for eachoperators position being divided into two parts 80 and means permitting only one unanswered call in each partsimultaneously 5, In a telephone exchange system, the combination with a telephone l1ne,-of an idle link circuit, automatic switching mechanism adapted to connect a calling line with and actuated over the calling telephone line,

the actuation of said relay being adapted to connect the normally open private conductor with a ole of the main battery whereby the link c1rc'uit will thereafter test busy so that no other calling line will be connected with this link circuit during the conversation and a-relay coil in circuit with said pri'vate conductor and energized over the said battery connection during conversation. '7

6. In a telephone exchange system, the

combination with a plurality of telephone lines; of a plurality of link circuits at a single operatorS position, automatic mecha nism adapted toconnect a calling line'with an idle l nk'circuit, normally open private conductors extending from the link circuits to the automatic switchlng mechanism, a

central source of current, a relay associated with the answering end of said'link circuit adapted to be actuated when a calling line is connected with the link circuit to establish the busy condition upon the private conductor extending to this link circuit and upon the private conductors extending to other link circuits at the sameoperators position, a relay associated with the calling end of.'said-1inkcircuit and adapted to be actuated, when a connection is established, with a desired telephone line, the actuation of said relay being. ada ted to remove the busy condition from sai other link circuits.

a 7. In a telephonesystem, the combination with a plurality of telephone lines, of a plurality of link circuits at a single operators position, switching mechanism-to connect a calling line with'an idle link circuit, private of said conductors being normally connected together at the link circuit end, means wherebythe [establishment of a call on'one of said link circuits places the busy condrtion'upon the private conductor of that link 1 circuit and upon the private conductors to which that private conductor was normally connected, and means whereby the establishment of a connection withadesired line removes the busy condition from the l tt P te OHduotors.

i 8.v In a telephone system, the combination with a plurality of telephone lines, ofa plu- 'rality of cord circuits, automatic switching mechanism to complete'the connection between a calling'line and an ldle cord cir- :.=conductors extending from the switching 1 mechanism to said link circuits, aplurality.

-;gether at the cord circuiti end and iextending :to the automatioswitching mechanism, .a}

)relay for the cord circuit actuated .over the calling telephone line, a secondrelay for the cord circuit actuated .over a :local circuit mined plurality of said indicators are simulwhen the calling end of the cordcircuit is connected with a ,desired line, the actuation of the first of said relays being adapted to ground allof said private conductors,- the iestablishingaaconnectionbetween a calling line, and -said cord circuit,- said Eintermediate switch ha i g motion in two directions, a cuaofi relay for. :the intermediate switch','.-=a

second relay actuated :through normal con- ,tacts ofsaid cut-ofi relaygthe actuation of the second relay 'beingmdapted to complete .the circuit of the mQtQr-magnet for moving the contacts of the intermediate switch in one actuation of the second relayl'being adapted to remove the ground .from allcxcept oneof said private conductorsand to maintain -,a

ground :upon the one private conductor so that the release of the first .relay not take the busy condition vate conductor. o

9. In a telephone system, the combination with'a plurality of telephone lines, oi'a-plurality of link circuits at asin'gle op'erators position, automatic switching mechanism adapted to connect a calling line with an off of the one priidle link circuit,,a conductor for eachlink circuit over which thezbusyoor'idlecondition of the link circuit is automatically tested by the automatic switching mechanism, the said link circuits for each operators position being divided into a plurality'of parts and means permitting only one unanswered-call in each part simultaneously,

10'. In a-telephone system, the combination with a plurality oftelephone lines, of a plurality :of link circuits in charge of a single operator',.autornatic switching mechanism for establishing .a connection between a calling line :and an idle one of said link circuits, an indicator displayed when 8.10311- ing line is connected with an idle link'circuit and means to prevent any other indicator from being displayed in this particu-' lar operators position when a predetertaneously displayed. A r

11. In a telephone exchange system, the combination with atelephone line, of a cord circuit, line and intermediate switch circuits for establishing a connection between a calling line and said cord circuit, said intermediate switch having motion in two directions, a relay'actuated over the linefor completing the circuit of the motor-magnet for operating the switch in one direction, a second relay actuated when the contacts of the switch come opposite a row having the contacts of an idle cord circuit therein to complete the circuit of the motor-magnet adapted to move the switch in the otherdirection, and a third relay adapted to be actuated when the wipers of the intermediate switch arrive upon the contacts of an idle cord circuit.

12. In a telephone exchange system, the combination with a telephone line, of acord circuit, line and intermediate switches for direction, a thirdrelay actuated when the contacts arrive oppositea row in which are the contacts of an idle-cord circuit, the actuation-of the third relay being adapted to complete the circuit .of the motor-magnet for ,moving the switch in the other direction until its tcontacts arrive upon theicontacts of ,an idle cord circuit, said cut- Oil relay being adapted to be actuated -when I :the' wipers of :the intermediate switch arrive uponthe contacts of an idle cord circult, the actuation of the cut-off relay-being adapted :to interrupt'thecircuits of said sec --ond and third :relays and to complete the talking circuit through .the intermediate switch.

- 1 13. In a telephone exchange; system, the combination with a' telephone line, of a.

cord circuit, line and intermediateswitches for establishing -.a connection between said line and said cord circuit, said intermediate-switch having motion in two directions,

a pair of motor-magnets, one for moving said switch in each direction, a source of interrupted current, a bank of contacts, a wiper sliding over said contacts when the switch moves in one direction,- one of said contacts corresponding to each row of cord circuit terminals with which the switch is adapted to connect, said contacts being adapted to have the busy condition placed thereon whenever all of the cord circuits in .the associated rows are busy, a relay adapted'to close the circuit of said interrupted ,source and, one of said motor-magnets through'said wiper-and said grounded contacts to cause the actuation of the motormagnet until said wiper arrives upon a non-grounded contact, a second relay having its coil connected between said wiper and ground whereby its coil is shunted whenrthe wiper is'on grounded contacts, the

actuation of said second relay being adapted to complete the circuit of said interrupted source through the other motor-magnet to-cause-the intermediate switch to move in the otherdirection torselect the idle cord c rcuit.

14. In a telephone system, the combination with a telephone line, of a switch at the central ofiice associated with said line, a pair of relays normally connected, one in each limb-of the telephone line and adapted to be simultaneously actuated to operate said line switch and select an idle trunk when the limbs of said line are closed at a the substation, the-actuation of one of said relays alone, when a'ground occurs upon a limb of the telephone line, being adapted to cau'se the continued rotation of said line switch Without selecting anlidle trunk.

15,.In a telephone system, the combinetion withl a telephone line,'of a line switch forestablishing an automatic connection, a

tion with a telephone line, of a plurality oftrunk circuits, a line switch for establish ing "the connection between said line' and any one of said trunk circuits, a grounded central source; of current, a pair of relays,

one connected between each limb. of said line and the opposite poles of saidsource, the actuation of both of said relays being'adapted to cause the: actuation of said line switch to select an idle trunk, and theactuation of one of said relays only being adapted to cause the continued movement of said line vswitch without selecting an-idle trunk.

17. In a telephone. systennthe combination with a telephone line, of a plurality of trunk circuits, a line switch for establishing the connection betweensaid line and an idle one of said trunk circuits, "a pair of relays actuated over the line when the limbs are connected together to cause the regular operation of said line switch,'-and meanswhereby a ground upon a limb of the telephone line will actuate only onevof said relays to cause the actuation of. said'line switch without selecting an idle trunk. 40

Signed by me at Rochester, county of Monroe, and State of New York, in the presence of two witnesses.

Witnesses:

H. W. LUCIA, GEORGE C. SLEMIN.

CHARLES E. HAGUE. i

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