US1233830A - Telephone-exchange system. - Google Patents

Description

J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM APPLICATION FILED DEC. 18. {9!4- v Patented J1 1ly17, 1917.

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IVIIQVESSES MWR My mi i J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED DEC. 18. 1914.

Patented July17, 1917.

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WITNESSES;

J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

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I/l/l/E/VTOR J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED DEC. 18, 1914.

Patented July 17, 19W.

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J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED DEC.18, 1914.

Patented July 1, 1917.

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WITNESSES: jiigE/VTOR J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED DEC. 18. I914.

Patented. July 17, 1917.

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QPR T EL S T I VITNESSES J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED DEC. 18. I914.

Patented July 17, 1917.

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APPLICATION FILED DEC-1811914.

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WITNESSES M All J. L. WRIGHT.

TELEPEIONE EXCHANGE SYSTEM. APPLICATION FILED DEC-18,1914.

Patented July 17', 1917.

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J. L. WRIGHT. TELEPHONE EXCHANGE SYSTEM.

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.I. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED DEC. I8. I9I4.

Patented July 17, 1917.

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I e N n K0 1 WITNESSES I l/VVf/I/TUI? M M do! ZLA/ erators position.

JOSEPH L. WRIGHT, OF CLEVELAND, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO

WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF YORK. I

TELEPHONE-EXCHANGE SYSTEM.

I Specification of Letters Patent. Patented July 1LT, T9111)? Application filed December 18, 1914. Serial No. 377,872.

To all whom it may concern:

Be it known that ll, JOSEPH L. WRIGHT, citizen of the United States, residing at Cleveland, in the county of Guyahoga and State of Ohio, have invented-certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a specification.

My invention relates to telephone exchange systems and especially to the type known as semi-automatic. In systems of this class automatic switches are utilized for efi'ectin connections between subscribers lines. ertain of these switches are purely automatic in their action and perform selections without such'selections beingpredetermined either by the subscriber or the operator. Other switches which are controlled by the operator perform their selections in a predetermined order.

'Heretofore corresponding switches which were driven in a predetermined manner were provided with test contacts and wipers for selecting trunks or terminals of other switches. With myinvention the calling lines are automatically selected by means of primary switches and these switches in turn are automatically connected to an idle op- The switches which are under control of the operator perform their selections in a predetermined manner with out the necessity of testing. Certain switches controlled by the operator are driven directly to contacts of called lines, while other switches are driven in a predetermined man'- ner to contacts associated with primary trunksto which calling lines are connected.

The calling lines besides being automatically connected to an operators position over what may be termed order trunks also cause to be indicated atsuch position the number corresponding to the number of the primary trun s. I The operator ascertains the number of the wanted line from the calling subscriber over these order trunks. In order to extend the connection, the operator is provided with a suitable key-board and sending device. The number of the primary trunk as indicated is registered upon the key-board as well as the number of the wanted line. By means of the impulse device a pair of coupled or mated switches are operated, one of which selects contacts corautomatically connecting her key-board or sending device with an idle service trunk. After an idle service trunk is selected the order trunk is automatically disconnected from the operators position and placed in readiness for receiving other incoming calls. The key-board and order trunk are not permanently connected and under ordinary conditions a single order trunk and single key board will be ample for one operator. While the connection is being established. between the primary trunk and the called'or'wanted line the order trunk is in position to receive another call While the operator is ascertaining the number of the wanted line the key-board is released and in condition to receive the registration of the second call.

Means are provided for maintaining the order wire trunk in association with the connection after it is extended to the wanted line in order that the operator may supervise the connection.

Other special features are provided whereby the ringing which is automatic is discontinued in case the called subscriber does not answer within a reasonable time. At this period the connecting switches are automatically released and a dont answer signal connected to the calling line.

Special releasing features are provided in connection with the connector switches whereby it is unnecessary for a calling subscriber to exercise control over the connector switch at any stage.

The method of emablishing a connection from a calling to a called line allows such connection to be completed within a very short period as. the plurality of'switches used in establishing the connection are operated at the same time.

' vertical Other features in connection with .the s stem will be pointed out in the detail descrlption to follow.

My invention is illustrated in the accompanying drawings wherein:

Figure 1 shows a subscribers line clrcuit and its controlling apparatus .at the central station. I

Fig. 2 shows a primary selector switch circuit.

.Fig. 3 shows a circuit of a connector switch and its associated trunk switch.

Fig. 4 shows the circuit of a called subscribers line together with its control apparatus.

Fig. 5 shows a key-set control circuit.

Fig. 6 shows an operators or order switch circuit.

Fig. 7 shows the. control apparatus associated with the key-board.

Fig. 8 shows an operators key-boa d and sending device.

Fig. 9 shows a control circuit for selecting an idle service trunk leading to associated connector and trunk switches.

Fig. 10 shows in detail' the wiring of the indicating lamps associated with the operators swltch.

Fig. 11 shows the arrangement of the various sheets.

Referring to Fig. 1,the subscribers station A is equipped with apparatus usual in common battery systems. The line wires from this station terminate at the central ofiice in a line relay 2. The line relays are divided into groups, there being ten groups to each one hundred lines. The windings of each group of ten relays are. common to the winding of a group relay 3 so that when any line relay is energized, the grou relay associated with it is also energize The group relay when operated makes the, row contact in the primary switch busy, while the line relay when operated makes the individual test contact in the primary switch busy I The switch W is common to a group of one hundred lines and is made to rotate whenever a call is originated. In rotating this switch picksout an idle primary switch i nd starts the samehunting for the calling Referring now to Fig. 2, the primary switch is shown at G. On the spindle of the switch is mounted a row wiper 64 which passes over the row contacts when the switch rotates. This switch first rotates. to pick out the group of callin lines and then steps y until the cal ing line is found. The tip and sleeve conductors are separated by the condensers 43 and 44. Relay 23 and the retardation coil 26 supply talking current'to the calling subscriber. Relay 21 is the starting relay of the primary switch and corresponds to the line relay 2, (Fig. 1)

as it controls the action of the operators key-set or order switch (Fig. 6). Relay 22 is the row test relay while 24 is the individual test relay. Relay 25 is operated when the key-set switch picks out the trunk. i

Relay 28 is energized whenever either the rotary or vertical magnets of the primary switch are operated. The circuits 'of these magnets are normally completed through the back contacts of this relay 28, and so therefore whenever it is actauted the magnet circuits are broken. The action thus set up between the relay and the magnets cause the latter to vibrate and continue to do so until their energizing circuits are opened.

Referring to Fig. 3, relays 351 and 353 are repeating relays of the trunk switch D while relays 352 and 354 are the repeating relays of the connector switch E. The operation of these relays control the respective magnets for causing the rotation and vertical stepping of the switches D and E respectively. Relay 350 is operated when an idle switch pair is selected. Relay 357 and retardation coil 358 supply current to the called subscriber. Relay 355 is the ringing relay while relays 367 and 368 are time element relays controlled by the disks K and L. These time element relays are used for causing the release of the switch D and the switch E in case the called subscriber does not respond during a predetermined period. The two disks K and L rotate .at a certain speed in the direction indicated by the arrow.

Referring now to Fig. 4, the subscribers station and line equipment is the same as that of Fig. 1. 7

Referring now to Fig. 5, the switch shown at Y corresponds to the switch W (Fig. 1) and picks out an idle key-set switch.

Referring now to Fig. 6, the switch M is similar and acts in the same manner as the primary. switch C (Fig. 2). The wipers 167 connect with the tip and sleeve side of the trunk shown in Fig. 2 over which the operator converses with the calling subscriber. 168 is the row wiper and picks out the particular group of trunks in which the calling trunk is located. Relay 154 is the individual test relay and acts when the trunk in the group is found. Relay 156 is the signal relay and pulls up in series with relay 25 (Fig; 2). Relay 152 is the starting relay and corresponds torelay 21 (Fig. 2), while 153 is the row test relay. Relay 155 is operated when the answering button 248 is depressed and connects the operators telephone set across the tip and sleeve conductors of the trunk.

Referring to Figs. 7 and 8, the operators key-board, sending device and controlling circuits are shown. The operators keyboard shown in Fig. 8 consists of five rows of buttons, each row having ten buttons. The first four rows of buttons R, S, T and U naeaeso I til.

are used in conjunction with the sending device for transmitting a predetermined number of impulses. Number 1 button of each of these rows is connected to a contact on the sending device operated by the cam 232. N o. 2-button of each row is connected to the contact operated by the cam 233. The corresponding buttons in each row are connected to similar contacts on the sending device. The contact controlled by the cam 232 is closed just long enough to maintain relays 202 and 203 (Fig. 7) energized While one impulse is being transmitted by each of the commutators 242 and'243. These commutators transmit impulses at the same time. If No. 10 button is depressed relays 202 and 203 will be controlled by the cam 241 to allow 10 impulses to be transmitted by the commutators 242 and 243. The contacts of these commutators are connected respectively to normally open contacts of relays 202 and 203. When these relays are operated the impulses are transferred to the tip and sleeve sides of the service trunks in a predetermined order, depending upon the position of the wipers 250 and 251 of the shifting switch N. v

The buttons or keys shown in the four rows R, S, T and U are of the usual locking and indicating type. When one button of a certain row is depressed it will release the button formerly depressed. The buttons in the row V are of thenon-locking type. When any one of these latter buttons are depressed it will operate an associated relay. In the present instance I have, shown the first two buttons connected to relays 200 and 201 respectively and it of course follows that there will be a corresponding relay controlled by each of the other buttons. The operation of these relays connects the sending device to the proper group of service trunks. Relay 204 is the signal or control relay and operated when an idle service trunk of the group is selected.

205 is the stepping magnetwhich controls the operation of the switch N. This stepping magnet is operated once at each rotation of the sending device by means of contacts controlled by the cam 231. This switch N operates on the back stroke of the magnet, that is to say after the magnet becomes energized and then'deenergized.

The rows of buttons It and S of Fig. 8 are used for operating the selected connector switch while the buttons T and II are used for operating the trunkswitch. The number of the primary trunk selected by the secondary switch is indicated to the operator'by means of two rows of indicating lamps as shown in Fig. 10. This figure shows how the lamps are connected to the designating contacts in the bank of the secondary switch. Qertain of these lamps are lighted depending upon which contacts are selected by means of the wiper 190 of the switch M as shown in Fig. 6. The operation of the secondary switch M in selecting the primary trunk also causes the wiper 190 to engage corresponding designating contacts in the bank; In case the primary switch or trunk selected should be No. 21 then the designating wiper 190 would engage the first set of contacts in the second row, causing lamps 2U and 1V to light, notifying the operator that the secondary trunk was connected to No. 21 primary trunk. The operator upon receiving these signals presses corresponding buttons in the rows T and U (Fig. 8).

Impulses from the rowsR and'll are transmitted at the same time while the impulses from the rows S and U are transmitted at the same time.

Fig. 9 shows the apparatus for selecting an idle connector and trunk switch in a particular group. When a particular group is selected by the operator the switch 0 rotates and selects an idle connector and trunk switch in the same manner that the switch a W (Fig. 1) selects an idle primary switch. In this particular instance, however, the selected trunk and connector switches re main in association with the operators position' during two steps of the switch 0 This switch first steps to select an idle switch pair after which the impulses are trans mitted at the same time operating the rotary magnets of the trunk switch I) and the connector switch E. The switch 0 is Ito then shifted and the impulses are transmitted at the same time to operate the vertical magnets of the trunk and connector switches. Relay 303 is a test relay for selecting an idle switch pair while relay 305 is operated after such a selection and'maintains' the selected switch pair busy against other calls. Relay 305 is slow acting and will not fully restore during a momentary opening of contacts of relay 300which controls its action. 4

Relays 300 and 204 are placed in series when either of the relays are operated by the depression of the buttons in the row V. Relay'204 will not operate in series with the winding'of relay 300 and the resistance coil 301, but after an idle switch pair is selected coil 301 is shuntedthereby allowing relay 204 to operate.

Each operator .is preferably provided with but a single key-board, shown in Fig.=

8, but the sending device shown in this figure may be common to a plurality of keyboards. In view of several calls being extended at the same time each operators keyboard is provided with individual commutators 242 and 243.

The mated switch "pairs shown in Fig. 3 are arranged in groups, the number of pairs in each group, of course, depend upon t'raflic conditions. Each service "trunk extending to the operators position is provided with a selecting switch 0 which is capable of selecting an idle switch pair in its particular group. Where several operators positions are provided it naturally follows that the contacts of the switches 0 serving particular groups of switch pairs are multipled,

The primary switches, secondary switches, trunk switches and connector switches are of the type shown in Patent No. 977,536 to 'This latter relay operating closes the circuit of relay 4 which in turn connects ground to one terminal of the relay 5 and also closes the circuit of the stepping magnet 7. The stepping magnet operating closes the circuit of relay 6 which in turn opens the circuit of the magnet itself causing it to vibrate and step the switch W. This switch will continue to rotate until an idle primar switch such as shown in Fig.2 is found. s soon as such a switch is found, the relay 5' is placed in series with relay21, (Fig. 2) by the following path: ground, contact of relay 4, 5, 18, W, 14, 21, 70, contact of relay 24 to battery B. The relay 5 operating opens the circuit of the magnet 7 bringing the switchW to rest.

Relay 21 operating closes the circuit of the rotary steppmg magnet 31 by the following path: battery B, 80, back contact of relay 24, 71, contact of relay28, back contact of relay 22, 31 to ground. The operation of magnet 31 causes the switch C to rotate until.

the wiper 64 reaches the busy row contact.

The wiper 64 is carried on the same spindle with the wipers 63 and 65, and while the switch is rotating the wiper 64 passes over contacts leading to the group relay 3. As there are ten of thesegroup relays to each one hundred lines it follows that the wiper 64 in rotating to its extreme position will pass over ten contacts.=

There are ten sets of individual contacts arranged in vertical rows associated with each row contact and which the wipers 63 and 65 respectively engage. It follows therefore that after the switch picks out the group inwhich a line is calling, it will afterward;

step vertically until the wipers engage the contacts ofthe calling line. 9

As soon as the row contact is found, the circuit of relay 22 is closed as follows: bah tery B, 80, back contact of relay 24, 71, 22,

the key-set switch finds the trunk. Relay 64, 13, contact of-rela 3, to ground. The relay 22 in operating isconnects the rotary magnet 31 and in its place connects the vertical magnet 30, thereby causing the switch to step vertically untilthe busy individual test contact is found. As soon as such a contact is found the circuit of relay 24 is closed as follows: battery B, 24,68, contacts of relay 22, 67, '11-, contacts of relay 2 to ground through the contacts of relay 1. Relay 24 operating opens the wire 71 and disconnects relay 22 which in falling backdisconnects relay 24 from the wire 67 and connects it instead to wire 66, thereby placing relays 24 and 1 in series.

The operation of relay .1 disconnects the line relay 2 and the group relay 3. Relay 24 connects battery to the windin of relays 23 and 25 and the falling back 0 relay 22 connects ground to the coil 26, thereby supplying the calling subscriber with talking current.

Relay 21 remains energized until the primary switch finds the calling line and until 21, when first actuated, places battery on the wire 7 9,to relay 130 and also places battery to wire'62 WhlCh is connected to the individual test contact of the key-set switch (Fig. 6).

Relay 130 closes the circuit of the stepping magnet 133 of the switch Y through the normally closed contacts of relays 131, 132. The magnet in operating closes the circuit of the interrupter relay 134, thereby causing the magnet to vibrate and the switch to rotate unt1l an idle key-set switch is found. When such a switch is found, as shown in Fig. 6, relay 131 is placed in series with relay 152 by the following path: ground, contacts of relay 130, 131, 138, Y, 14.0, 152, 195, 196, 197 to battery B through the operators jack 400. Relay 131 operating places battery on wire 136 to relay 132. As soon as this latter relay operates, ground is placed on the wire 138, thereby shunting relay 131. This direct ground placed on wire 138 makes the wire 140 which is multipled to otherY switches busy. The operating of relay 132 also places ground on the row wiper of the key-set i switch by the following path: ground, 139,

Y, 141, to the row contact.

The operation of relay 15 2 connects ground to the rotary magnet 165 through the back contact of relay 153 causing the switch M to rotate. This switch will rotate until the busy row contact is found, whereupon vertical magnet 164, thereby causing the switch to step vertically until the busy individual test contact is found. The finding of this contact closes the circuit of relay 154 as follows: ground, 154, 172, 62, 80, contacts of relay 21 to battery B. Relay 154 disconnects relay 152, thereby cutting off the vertical magnet and causing the keyset switch to rest'on contacts leading to the calling primary trunk. Relay 152 becoming disengaged opens the circuit of relay 153 and this latter relay in falling back places relays 156 and 25 in series by the following path: ground, back contact of relay 153, 175, back contact of relay 157, 202, contact of relay 155, 156, 193, 169, 59, 25 to battery B through the contact of relay 24. The operating of relay 25 (Fig. 2) disconnects relay 21 and also relay 5 (Fig. 1). The releasing of relay 5 frees the switch W allowing it to pick out other primary switches. Relay 156 operating places battery on wires 181 and 183 causing the lamps 234 and 244 to light.

As soon as relay 21 in Fig. 2 became disconnected battery was removed from the individual test contact of the key-set switch, thereby allowing relay 154 to fall back. Belay 21 also releases relay 130, thereby restoring relay 132 so as to allow the switch Yv to be used by other trunks in picking out key-set switches.

In the present instance I have provided ten primary switches as shown in Fig. 2 foreach one hundred lines. Each group of ten primary switches is in turn provided with one Y switch for picking out idle keyset switches. The percentage and grouping of the trunks and lines can be varied to suit traflic conditions.

The wire 141 leading from the Y switch to the row contacts of the key-set switch is not multipled., The Y switch picks out an idle key-set switch and this places ground on the row contact ofv the selected switch and these row contacts are not multipled. This arrangement prevents interference between other Y switches and also between the key-set switches. Tn no case is ground placed on more than one row contact of any key-set switchat the same time.

In Fig. 1 the switch W is individual to one hundred lines and picks out a group of primary switches, and in this case the row contacts of a group of primary switches are multipled.

The lighting of the lamps 234 and 244 notifies the operator of a call, and she then presses button 248 closing relay 155. The operation of this relay connects her telephone set across the trunk wires, disconnects relay 156,. thereby extinguishing the lamps 234 and 244. The disconnecting of relay 156 also opens the circuit of relay 25,

' against other calls.

(Fig. 2) which in falling back closes the tip and sleeve conductors of the trunk, allowing the operator to converse with the calling subscriber.

The operation of the switch M also causes the lighting of a lamp in each of the rows shown in Fig. 10. The lighted lamps correspond to the number of the primary trunk or switch which selected the calling line.

The operator after receiving the number from a calling subscriber depresses buttons in rows R and S corresponding to the tens and units digits. The operator also depresses a button in the row- T corresponding to the lamp lighted in the row TT, and also depresses a button in the row U corresponding to the lamp lighted on the row UU. After depressing these buttons the operator depresses a button in the row V corresponding to the hundreds digits of the called subscriber. Tn the present instance we will assume that the first button is depressed; the depressing of this button completes the circuit of relay 200. The operation of this relay connects the winding of relay 204 and the winding of' relay 300 (Fig. 9) in series with the resistance coil 301. Belay 200 remains locked to ground through the back contacts of relay 206 and the button 208. Relay 300 becomes energi-zed but relay 204 is not operated due to the high resistance of coil 301. The operation of relay 300 completes the circuit of the stepping magnet 304 of the switch 0 by the following path: ground, contacts of relay 300, contacts of relay 302, winding of magnet 304 to battery B. The operation of the magnet. completes the circuit of the interrupter relay 302 by the following path: ground, contacts of relay 300, 314, contacts of relay 305, 315, 316, winding of relay 302 to battery B. The operation of relay 302 opens the circuit of the magnet 304 and the magnet in restoring again allows relay 302 to drop back. This action between the magnet and relay 302 causes the switch 0 to rotate until an idle switch pair is selected. As soon as such a switch pair is selected, such as shown in Fig. 3, then relays 303 and 350 are placed in series by the following path: battery B, contacts of relay 300, 32c, winding of relay 303, 325,312, 324, winding of relay 350, 377, cam springs 370 to ground. The operation of relay 303 completes the circuit of relay 305. This latter relay in operating connects battery directly between the winding of relay 303 and the testing switch wiper 312, thereby rendering the contact upon which the wiper rests busy The effect of battery being connected in this manner shunts relay 303 causing it to restore, but relay 305 remains locked to ground through the contacts of relay 300.

' tacts and engage the second set.

The operation of relay 305 also connects ground between the winding of relay 300 and the coil 301, thereby shunting out the resistance. The shunting out of this resistance allows relay 204 (Fig. 7) to become energized. The operation of this relay then causes the lamp 207 to light, notifying the operator that an idle switch pair has been selected. The operation of relay 204 also causes the release of the switch M by the following path: ground, contacts of relay 204, 152, contacts of relay 160, winding of relay 157 to' battery B. The operation of this relay 157 completes the circuit of the release magnet 166 by the following path: ground, contacts of relay 153, 175, contacts of relay. 157 170, winding of relay 166 to battery B. The operation of this magnet causes the restoration of the switch M thereby allowing it to be used for other incoming calls.

The button or key 104 is manipulated by the operator before setting up the number on her key-board. The'operation of the button 104 allows the switch M to be automatically restored as soon as the operators sending device is placed in association with an idle switch pair. 7

In order to prevent the automatic d1sconnection the operator may neglect to press the button 104 but release the switch M by operating the button 101.

In case all of the switch pairs are in use the operator can press the button 105 thereby connecting ground to the trunk conductor 150. This trunk conductor extends to the primary trunk conductor 53 through the switch wiper 167. Connecting ground in this manner causes the operation of relay 29 which in turn connects a suitable busy tone test to the trunk conductor 51, notifying the calling subscriber that the trunks are busy.

The operation of relay 204 after an idle trunk switch pair is selected, also completes the circuit of the stepping magnet 205 of the switch N so that it can be operated by the springs controlled by the cam 231 of the sending device. As soon .as the contact springs controlled by this cam are operated then the magnet 205 is operated and after the contacts are broken the switch wipers 250, 251 anti 252' leave the first set of con- It will be noted that the winding of'relay 204 is connected to battery through normally closed contacts of the magnet205 and to batterythrough the contact upon which the switch wiper 252 .normally rests. After the switch takes the first step then battery connection to the relay 204 p is controlled wholly through the contacts of the magnet 205.

After taking the first step the common wire 258 of the row of buttons R is connected directly to the winding of relay 202 through the switch wiper 250 and the common wire of the row of buttons T is connected directly to the winding of relay 203 through the wiper 251. Relays 202 and 203 are maintained energized for a certain length of time, depending upon the buttons depressed in the rows R and T. Impulses corresponding to the number of buttons depressed in these rows are transmitted by means of the commutators 242 and 243.

The connector switch E is operated by means of impulses from the commutator 243 while the trunk switch D is operated by means of impulses transmitted by the commutator 242.

After wipers of the switch N engage the second set of contacts then relay 202 is energized and held energized for a length of time, depending upon which button is depressed in the row R. Relay 203 is likewise held energized for length of time, depending upon which button is depressed in the row T, The impulses from the commutator 243 are transmitted to the rotary relay 352 of the switch E by the following path: ground, commutator contacts 243, 262, contacts of relay 202,263, contacts of relay 200, 212, 311, 323, winding of relay 352 to battery B. The operation of this relay a number of times according to the button depressed in the row R causes a corresponding operation of the rotary magnet362 by the following path: ground, contacts of relay 352, 374, cam springs 371, 375, winding of magnet 362 to battery B. The operation of this magnet causes the switch E to rotate and bring its wipers in line with a row of contacts containing the terminals of the called line.

The impulses from commutator 242 causes the operation of the rotary relay 351 of the trunk switch D by the following path: ground commutator contacts 242, 260, contacts of relay 203, 261, contacts of relay 200, 211, 310, 321, winding of relay 351 to battery B. The operation of this relay a number of times corresponding to the button depressed in the row T causes the operation of the rotary magnet 361 which causes the switch D to rotate and bring its wipers in line with contacts leading to the proper group of primary trunks.

After the termination of these impulses the circuit of the magnet 205 of the switch N has its circuit completed by the springs controlled by the cam 231. While the magnet circuit is closed the circuit of relay 204 is brokenv by battery being disconnected from its winding. The opening of this relay circuit causes its deenergization as well as the denergization of relay 300 with which it is in series. The only effect of relay 204 restoring is to cause the signal lamp 207 to be momentarily extinguished. Relay 300, however, in restoring removes ground from the winding of magnet 304. thereby causing the wipers of the-switch O to take one step. In taking this step the relays 351 and 352 are disconnected respectively from the trunk conductors 212 and 211 and relays 353 and 354 connected instead.

As soon as the impulse transmitted by the cam 231 has been delivered then the stepping mafgnet 205 restores and causes the wipers 0 the switch N to engage the th1rd set of contacts thereby connecting the common conductors 257 and 255 of the rows of buttons S and U to the conductors 264 and 265 respectively.

The momentary. dropping back of the relay 300 does not release relay 305 as it is made slow acting for this purpose. The wiper 312 moving from the contact to which is directly connected the winding of relay 350 still maintains that relay energized as the next contact is connected to a contact of relay 350 which engages a contact leading to the winding of the relay itself. With this method of control the relay 350 is originally energized over but a single test contact and after it'is once energized it is thereafter controlled over two contacts. The operation of relay 305 of course maintains direct batter connection to the two contacts after re ay 350 is onceenergized, thereby preventing the selection of that trunk by another switch 0. The operation of relay 305 also removes ground from the contact springs of magnet 304:, preventing the operation of the interrupter relay 302.

After the switch N engages the third set of contacts then relays 202 and 203 are maintained energized for length of time depending upon the buttons depressed in the rows S and U. The operation of relay 202 causes impulses to betr'ans'mitted from the commutator 243 to the vertical relay 354.. The operation of this relay completes the circuit of the vertical magnet 36 1 thereby causing the. switchE to step vertically and bring its wipers to rest on contacts corresponding to the button depressed in the row S.

The operation of relay 203 causes impulses to be .transmitted from the commutator 242 to the vertical. relay 353 of the switch D. The. operation of this relay completes the circuit of the vertical magnet 363 and causes the switch D to step vertically and bring its wipers into engagement.

with contacts leading to the calling primary trunk corresponding to the button depressed in the row U. The button in the row U of course correspondsto the lamp which was lighted in the row DU.

After the impulses have been transmitted to the switches D and E the circuit of the stepping magnet 205 of the switch N is again completed by means of an impulse transmitted by the cam 231. After the impulse has been delivered the wipers of switch N step to their fourth or normal position. In taking this step the wiper 252 passes over the contact 270 thereby momentarily energizing relay 206. The operation of this relay removes ground from the locking contact of relay 200 thereby disconnecting the sending device from the switches D and E. The restoration of relay 200 severs the connection between relays 204: and 300, and the latter relay in restoring removes ground from the locking contact of relay 305, and after a short interval of time this relay restores and places the switch 0 in condition tobe again used for other calls. The restoration'of this relay removes battery from the test wiper 312 of the switch 0 and the restoration of relay 300 removes battery from the winding of relay 303,.thereby opening the'circuit of relay 350. This relay in restoring in turn opens the circuit of the slow acting relay 390. Before relay'390 restores ground is connected to the winding of relay 352 by the following path: ground, contacts of relay 350, contacts of relay 390, winding of relay 352 to battery B. The operation of relay 352 at this time while the switch wipers are resting on contacts of the called line connects the test relay 366 to the test wiper 373 by the following path: ground, winding of relay 366, 382, contacts of relay 352, 381, test wiper 373. In case the called-for line is busy rela 366 will be momentarily energized an connect ground directly to the conductor connected to the switch. wiper 395. As this switch wiper is engaging contactsof the primary trunk to which a call.- ing line is connected then relay 29 becomes operated. This relay in operating remains locked to ground through the cam springs 38 in series with the resistance coil 49. This relay while operated connects a suitable. busy tone signal to the trunk conductor 51 which notifies the calling subscriber that the called- .365 and 391 respectively of the switches D and E thereby causing their restoration. In case the called-for line is not busy then relay 366 is not afiected and the connection remains extended to the called line.

The operation of relay 352 in case the called line is not busy completes the circuit of relay 367 by the following path: ground, contacts of relay 366, contacts of relay 352, 374, cam springs 371, 376, winding of relay 367 to battery 13, through the contact springs controlled by the disk K. The operation of relay 367 in turn completes the circuit of relay 368. The operation of these two relays has no efi'ect upon the connection unless the called subscriber fails to answer after a certain time, that is to say after his line has been rung a certain number of times.

After relay 390 restores the tip and sleeve trunk conductors are closed and relay 356 has its circuit completed. by the following path: battery B, contacts of relay 390, winding of relay 356, contacts of relay 352,381, wiper 373 winding of the cut-off relay of the called line, to ground. The operation of relay 356 connects ground to the Winding of the retardation coil 358 and battery to the winding of relay 357 in order to supply talking current for the called subscriber. The operation of relay-356 al'socompletes the circuit of the ringing relay 355 by the following path: ground, commutator I, winding of relay 355, contacts of relay 359, 390, contacts of relay 356 to battery B. The operation of relay 355 is intermittent, being controlled by the commutator I. During each energization of relay 355 the trunk conductors are severed and generator current G is connected to the called line. When the called subscriber removes his receiver the tip relay 357 is energized and when operating completes the circuit of relay 359. The operation of this latter relay opens the circuit of the ringing relay 355 and prevents further application of ringing current.

The connected switch pair is rendered busy against other calls as the starting circuit for relay 350 is opened at the cam springs 370.

After the called subscriber replaces his receiver relay 357 restores and completes the circuit of the release magnets 391 and 36 5 by the following path: ground, contacts of relay 357, 383, contacts of relay 359, 380, to the winding of magnet 391 to battery B, and also to the winding of the magnet 365 to battery B. The operation of these two magnets causes the restoration of their respective switches. The restoration of the switch E causes the cam springs 370 to operate and open the circuit of relay 359. v

The operation of relay 357 when the called subscriber removes his receiver also causes ground to be removed from the locking contacts of relays 367 and 368 thereby causing their restoration.

The calling subscriber replacing his receiver causes the restoration of relay 23.. The restoration of this relay completes the circuitof the release magnet 32 by the following path: battery B, contactsof relay 25, 76, contacts of relay 21, 75, earn springs 39, 74, contacts of relay 23, 73, winding of magnet 32 to ground. The operation of this magnet causes'the restoration of the switch 0..

In case the called subscriber does not answer within a certain time, the period of which is controlled by the speed of the disks K and L, the switches E and D are automatically released and a suitabled0nt answer signal connected to the calling or primary trunk. The operation of relays 367 and 368 have been previously described. When the cam springs controlled by the disk K are opened relay 367 restores and a complete rotation thereafter causes the restoration of relay 368. It will be noted that the cam springs controlled by the disk L are opened 'in advance of the springs controlled by the disk K. Under these conditions relay 368 willbe momentarily deenergized but will become again energized as relay 367 is operated. When the cam springs, however, controlled by the disk K are operated relay 367 restores. At this stage no effect is produced, but when the springs controlled by the disk L are opened relay 368 becomes deenergized and as relay 367 is deenergized at this time relay 368 remains deenergized. Under these conditions the circuit of relay 399 is completed by the following path: ground, contacts of relay 357, 383, contacts of relay 359, contacts of relay 367, 385, contacts of relay 368, 386; contacts of relay 356, 387, winding of relay 399 to battery B. The operation of relay 399 connects ground to the wiper 395 thereby operating relay 27 associated with the primary trunk. The operation of this latter relay connects a suitable -dont answer signal to the trunk conductor 51 notifying the calling subscriber that the called subscriber does not respond. The operation of relay 399 also completes the circuit of relay 359. The operation of this relay while relay 357 is denergized allows the circuits of the release magnets 365 and 391 to be completed by the path previously traced.

The calling subscriber receiving the indication that the subscriber called for does not respond replaces his receiver and causes the restoration of the switch C as previously described. The restoration of this switch opens the locking relay 27 thereby removing the dont answer signal from the trunk conductor 51.

From the foregoing description it will be seen that the connections between the calling and called subscribers lines are effected with great rapidity. The directively driven switches for effecting the connections are operated at the same time as the operators eiuipment is so arranged that two groups 0 impulses are transmitted at the same time to operate these switches. 'So far as I am aware this is a new method of establishing connections as it is the usual custom in automatic or semi-automatic systems to operate the directively driven switches one at a time in a'certain order.

It will also be noted that the trunk switches are not provided with testing contacts but are driven directly to the primary trunks to which the calling lines are connected. The service trunks which may be few in number are provided with the necessary testing contacts for selecting an idle switch pair.

In the present instance I have shown the service trunks terminating in contacts of relays associated with the operators positions. Of course, these trunks can terminate on what may be termed trunk jacks. These trunk jacks can be multipled to different operators positions, a suitable busy tone signal being providedeither in the form of busy'indicatinglamps or the ordinary audible test such as commonly used in connection with multiple switch boards.

Instead of providing relays or trunk jacks the row of buttons designated as V can be provided with the proper number of contacts so that when a particular button is depressed it will connect the controlling apparatus shown in Fig. 7 to the proper service trunk. This row of buttons can be provided with a release magnet for releasing the'depressed button upon the operation of relay 206 which can be provided with a suitable contact for that purpose.

Instead of providing the designating lamps shown in Fig. 10 and which are connected to contacts inthe bank of the operators switch these lamps can be dispensed with. In place of the lamps the proper contacts in the bank can be connected to corresponding contacts controlled by the cams on the sending device, Fig. 8. In this event the rows of buttons T and U will not be used as the common wires 255and 256 would be connected respectively to the tip and sleeve conductors of the wiper 190 of Fig. ,6, and the ground connection omitted. With this arrangement button 104 will not be operated and the switch M would remain in engagement with the primary trunk until connection was eifected with the calledline. The designating contacts in the bank such as shown in Fig. 10 instead of being'connected to the lamps will be connected to the sending device in the sa'memanner as the contacts in the rows T and U of the key board.

From the foregoing it will be seen that many modifications may be made with the type system disclosed without departingfrom the spirit of my invention.

Having thus described my invention, what I desire to secure by Letters Patent is:

1. A telephone exchange system including a calling subscribers line, terminals therefor at the exchange, of a primary trunk circuit adapted to, be automatically connected with said line upon the initiation of a call, an operators position and. order trunk leading thereto, an electrically controlled selective switch at the exchange, means for initiating travel thereof to connect said primary trunk and order trunk in response to the operation of said selective switch, it called subscribersw line, terminals therefor at the exchange operators means for transmitting directive currents over a circuit separate from said trunk line to establish a connection from the terminals of the calling line to terminals of the called line, with means for freeing said order trunk at the initial transmission of the directive currents.

2. A telephone'exchange system including a calling subscribers line, terminals therefor at an exchange, a central office primary trunk circuit adapted to be automatically connected with the line upon the initiation of a call, an operators position,'an order trunk leading thereto, an electrically controlled selector switch at the exchange, means for initiating travel thereof to connect said primary trunk circuit and order trunk in response to the operation of said selective switch, a called subscribers line, terminals therefor at the exchange, a pair of directively operable selective switches, one of said switches containing in its contact banks terminals of the primary trunk and the other terminals of the called line, operators means for electrically controlling the adjustment of said selective switches to complete the connection from the terminals of the primary trunk to the terminals of the called line.

3. In a telephone exchange system, a number of subscribers lines, a number of primary trunks less than the number of lines, each trunk terminating at one end in a primary selector switch and at the other .end in terminals associated with a trunk switch, an operators position, a secondary switch associated with said position and containing terminals of" a number of said primary trunks, all of said secondary switches adapted to be started up to test and connect with terminals of said primary trunks, additional means controlled at said operators position for causing the trunk switch to efi'ect connection with terminals of the primary trunk.

4 A telephone exchange system including telephone lines, primary selectors for automatically connecting calling lines with primary trunks, of a plurality of permanently connected switch pairs at the exchange, each pair including a connector switch provided with contacts for selecting the called line, the other switch of each pair beinga trunk switch for connecting with the primary

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