US1245438A - Telephone-exchange system. - Google Patents

Description

H. P. CLAUSEN. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JUNE 7. l9l5- W/inesses:

/n Ven/or: Henry Claus en H. P. CLAUSEN.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION men JUNE 1. 1915.

Henry I? C/ausen odmw y I b fAiyy H. P. CLAUSEN. IELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JUNE 7. 1915- 1,2%5,438. Patented Nov. 6, 1917, w 4SHEETSSHEET 3.

Henry R Cyan/sen H. P. CLAUSEN.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED IUNEY- 1915- 1 $45,438. Patented Nov. 6, 1917.

4 SHEET$SHEET 4- lnvenfor: Henry 1? C/ausen y W/fnesses:

UNITED STATES PATENT anion EENRYPETER CLAUSEN, 'OF MOUNT VERNGN, NE'W "SIDE/K, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 WE$TERN E ECTRIC GClt -NY, INCORPORATED, A CORPORA- TION OF NEW roan.

'IELIElI-IONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Application filed June 7, 1915. Seria1No.32,693.

To all whom it may concern:

Be it known that I, HENRY PETER CLAU- SEN, a citizen of the United States, residing at Mount Vernon, in the county ofWestchester and the State of New York, have invented certain new and useful Improvements in TelephoneExchange Systems, of which the following is a full, clear, concise, and exactdescription.

This invention relates to line selectors or connectors, and particularly to means associated therewith for testing the. lines. It is especially applicable to connectors of automatic. and semi-automatic telephone exchange systems.

It is desirable for traffic reasons in a telephone exchange system to permit certain operators, such as the operators at a toll or long distance switchboard or incoming operators, to establish connections with wanted lines regardless whether they are at the moment busy or idle. Thus in an auto matic or semi-automatic exchange it becomes necessary, in order to meet the traflic requirements referred to, to force connections to busy lines in some manner regardless of the testing means at the connectors which ordinarily operate to reject connections to busy lines. It is the object of this invention to enable any connection, available through a connector switch acting under the control of a sender, to be extended to or to be rejected by a busy line, at the will of the operator or other person manipulating the sender, and to automatically apply the busy test condition to an idle line when a connection thereto is established through a connector without regard to the previous test condition of the selected line.

In accordance with one feature ofthe invention the incoming line, 2'. c. the line extending between the sender and the connector, is available not only for controlling the selecting operation but also for controlling the testing means thereof, whereby, if desired, it may be rendered temporarily ineffective. The invention provides, furthermore, a no test controlling device or key at the sender, which may be adjusted by the operator before or during the sending op eration, and which shall automatically cause a change to occur in the testing means after the line wanted is selected and before said testing means can become effective to reject a busy line connection. The change in Patented Nov. 6, 1917.

the testing means referred to may be rendered effective at the proper time by shunting the high resistance winding of a test relay associated with the line selector so as to make the operation of this relay possible irrespective of the electrical conditions existing on the called line. when thus energized or some other automatically available means, may be caused to apply the busy test condition to the selected line so that this line, if it had happened to have been idle, will quickly be made busy to other selectors operated in the ordinary way.

The invention will be more fully understood by reference to the accompanying drawings illustrative of the circuits of a semi-automatic system. Figures 1, 2 and 3 are to be placed adjacent one another from left to right in numerical order, and Fig. 1- below Fig. 1. Fig. 1 represents a toll line and connecting apparatus of a toll operators switchboard, and the circuits of a cordless incoming selector; Fig. 2, part of the circuits of aline selector or connector; Fig. 3, diagrammatically, certain portions of the connector structure, part of the circuit connections thereof, and the circuits of the local subscribers line; and Fig. 4, certain of the circuits of a sender apparatus adapted for manipulation by an operator when asso- The test relay i ciated with the cordless incoming selector 7 For the purpose of producing various circuit changes required at the incoming selector (Fig. 1), there is provided a sequence switch 100. The circuits of the line selector tain other sequence switch positions than those indicated adjacent to the sequence switch contacts may be used. For example, positions 2 to 12 inclusive of the sequence switch may be utilized for the control of the circuits during the selecting operations of the incoming and line selectors preceding the final or units operation of the latter, which occurs in position 13 of the sequence switch 100, position 6 of sequence switch 200, and position 13 of sequence switch 400. As the preliminary selecting operations, however, do not have any special bearing on the invention claimed herein, and for the sake of brevity, a description of the operations which take place in them and the detail circuits involved therein are omitted.

The heavy black lines running througn Figs. 1 to 3 inclusive indicate the conductors through which a telephonic circuit may be established from station A. of a toll line to station B of a local subscribers line. This connection in part includes means, such as an answering plug and jack of an automatic switch, by which the call from station A is extended to a connecting circuit 101 of a toll operators position, and a calling plug 102 and trunk jack 103, which the call is extended to the circuits of a cordless incom ing selector 10% (Fig. 1). The latter connection may be established in accordance with instructions given by an incoming operator to the toll operator over an order wire, as to the particular incoming trunk or selector which the former operator assigns for the connection. By means of such an order wire (commonly used and not sh wn in the drawings), the toll operator had pre riously announced to the incoming operator the number of the wanted subscribers line. When the incoming operator has assigned the trunk, she depresses an ass gnment key 105 which starts into operation apparatus for temporarily associating a sender appa ratus (Fig. 4) to the assigned trunk. The connection between the trunk and the sender may be made through the usual cord finder 4101., certain of the contacts of which are shown. The connecti on having proceeded as stated to the cordless incoming selector 10%, and the sender of Fig. 4c having been connected to the incoming trunk, the incoming trunkopcrator proceeds to effect the operation of the selector switches in the usual way. The operator may, for example, register the number on a series of keys of any known form of sender or controller. Such a keyboard and the detail circuits thereof not being material to the invention are not shown in the drawing, but there is shown for convenience in tracing the sequence of operations the immediate circuit connections of a well-known counting relay sender effecting the operation of the selector switches. Under the control of such a sender the operat'ormay first cause the incoming selector 10-1- to extend the call. to a trunk leading to the circuits of a line selector 301 havingaccess to a group of lines including the particular line wanted. The operation is effected automatically until the final selector brushes are adjusted to the terminals of this line.

The structure and arrangement of the sender has no bearing 0n the present invention. Preferably it is of the type described in a. Patent No. 1,168,319, patented January 18, 1916, to A. E. Lundell, but any other revertive impulse sender; that is to say, a sender which is adjusted to receive a certain number of impulses in response to the opera tion of selectively operable switching de vices, may be used without departing from the spirit of the invention. Obviously, instead of a revert ive impulse sender, an inn pulse sender may be used by means of which the selector switches are directively set.

Only a general outline of the sender a rrangement shown in the mentioned patent is given in the drawings, and the operating positions of the sequence switches shown in Figs. 1 and t are different from those used in the cited patent. The cord finder X shown in Fig. 2 of thepatent, is represented at 401; only two wipers 4-08 and 109 and two terminals adapted to be engaged by the wipers being shown. These wipers corre spond to the third and fifth wipers of the cord finder shown in the mentioned patent. In order to simplify the circuits shown in Figs. 1, 2 and 3 of the patent, a single circuit is shown extending between the sender and the controlling apparatus of the selector 104, where a plurality of circuits are shown in the patent. Only one sequence switch 400 is shown in Fig. 4 for performing functions which are usually performed by two sequence switches. This sequence switch therefore is a combination of the sequence swit .hes 800 and 400 shown in the patent. U der the control of a circuit including conductor 4105i and a sequence switch contact 119, the sequence switch 400 may be moved out of pos tion 1. Sequence switch contact 119 is a combination of sequence switch contacts "206 and 208 of the patent, conductor $03 cor sponds to conductor 305, and sequence switch sprin Oi to sequence switch spring 30-" of the patent. Relay r05 corresponds to relay 30! of the patent. In order to simplify the circuits, this relay is shown as controlling the movement of sequence switch 4-00 out of position 1, although relay 300 does l performthis function. Instead of the en ,rgiaing circuit including the right-hand win ing of relay 309 of the patent, and the holding circuit including the left-hand armature and "incling of relay 309, a single circuit is shown including the right-hand top contact of sequence switch spring etO-i, conduclay 403, and relay 417 to relay 402. Gonductor 412 corresponds to conductor 244, sequence switch spring 126 to spring 215, and relay 124 to relay 212 of the patent. The conductor 235 and sequence switch contact 234 of the patent which are used when sending impulses beyond the selector shown in Fig. 1 of the patent are left out, conductor 412 and sequence switch spring 126 being used for this purpose. Conductor 411, by means of which sequence switch 100 may be moved into the talking position, corresponds to conductor 245 of the patent, and sequence switch spring 426 to sequence switch spring 429 of the patent.

In a manner to be described more in detail later, the test relay 201 (Fig. 2) of the line selector 301 is ordinarily rendered effective immediately after the adjustment of the line selector 301 to test the condition of the selected line. But it it should be desired that the connection shall be established to this line regardless of whether or not it is busy, the high resistance winding of the test relay is short-circuited for allowing this relay to permit all its functions irrespective of the busy condition to the selected line. In a no test operation the high resistance winding of relay 201, as will appear more in detail later, is short-circuited a moment after the selector brushes are adjusted, a circuit path being provided for this purpose over the incoming trunk line from the sender (Fig. 4). If it had been desired by the toll operator that the connection be made regardless of the line condition, she would have instructed the incoming operator to that effect, and the latter operator, preferably before operating the sender, would have depressed the no test key 402.

More in detail, the operation of the system is as follows:

Subscriber A desiring to initiate a toll call removes his receiver from the switchh'ook and causes thereby, in the well-known manner, the automatic or manual extension of his line 104 to an operators cord circuit 101. The operator having learned by means of her telephone set (not shown) the number of the desired subscriber, transmits this number to an incoming or recording operator over an order wire (not shown), and extends the calling line by inserting plug 102 into jack 103 to a trunk line 106, 107, in accordance with instructions received from the incoming operator. A circuit is closed now from ground through resistance 108, sleeve contacts of jack 103 and plug 102, and the coil of relay 109 to grounded battery, and the potential on the multiples of the sleeve of jack 103 is reduced to guard trunk line 106, 107 against other incoming calls. A further circuit is closed from one side of battery 110 through the upper winding of relay 111, upper contact of relay 112, primary winding of induction coil 113, trunk line 106, tip side of jack 103 and plug 102, cord circuit 101 including the winding of supervisory relay 114, and back throughthe ring side of plug 102 and jack 103, trunk line 107, primary of induction coil 113, lower contact of relay 112 and lower winding of relay 111 to the other pole of battery 110. Relays 114 and 111 become energized, the former causing the lighting of supervisory lamp 115, and the latter the energization of relay 116. i v

The incoming operator proceeds now to cause the building up of a connectionbetween the calling substation A and the called substation B. First she depresses .her assignment key 105 closing a circuit from ground through key 105, sequence switch spring 117 (in position 1), and power magnet of sequence switch 100 to grounded battery. Sequence switch 100 leaves its first position and moves, under the control of the normal spring 118, into position 13. In position 2 of sequence switch 100 a circuit is closed from ground through sequence switch spring 119, conductor 403, spring 404 of sequence switch 400 (in position 1), and Wind ing of relay 405 to grounded battery. Relay 405 upon energization closes a circuit through its armature and front contact and sequence switch spring 406 for the power magnet of sequence switch 400, and this sequence switch is under the control of its normal spring 407 moved into position 13.

After sequence switch 400 leaves its first position relay 405 is maintained energized through the right-hand top contact ofsequence switch spring 404, conductor 410 and sequence switch spring 120 to ground. lVhile sequence switch 400 is moving from position 1 to 13, circuits are established, causing cord finder 401 to hunt with its wipers 408 and 409 for conductors 411 and 412 assigned by the incoming operator, and after the cord finder brushes have been set, the incoming operator sends out the first set of numerical impulses designating the called line, and causes, in the well-known manner, switch 104 to engage with its wipers 121,122 and 123 the contacts in which terminate trunk 202, 203 and 204 leading to the final selector or connector 301. The setting of the selector switch 104 is accomplished before sequence switch reaches position 13.

In position 12 of sequence'switch 100 and position 13 of sequence switch 400, a circuit is closed from grounded battery through the coil of relay 124, sequence switch spring 125 (in position 12), sequence switch spring 126, conductor 412, cord finderv brush 409, sequence switch spring 415 (in positions 1 to 18 and 13), resistance 416, windings of counting relay 417, and back contact and armature of relay 418, to ground. Relay 124 by attracting its right-hand armature prepares a locking circuit for itself, and when sequence switch 100 reaches its 13th position this locking circuit is completed through sequence switch spring 125 (in position 13 'to 17).

When the wipers of selector switch 104 are set, a circuit is closed from ground through the left-hand armature and front contact of'relay 124, right-hand bottom contact of sequence switch spring 127, wiper 121, conductor 202, sequence switch spring 205 (in positions 1 to 7%; and 1, 7), conductor 206 and winding of relay 207 to grounded battery. Relay 207 becomes energized and closes a circuit from ground through its left-hand armature and front contact, righthand top and left-hand bottom contacts of sequence switch spring 208, and winding of relay 209 to grounded battery. Relay 209 upon energization causes sequence switch 200 to leave its normal position and to move into position 6, by closing a circuit from ground "through its left-hand armature and front contact, sequence switch spring 210, and the power magnet of sequence switch 200 to grounded battery. Relay 209 will not become deenergized when sequence switch leaves its first position, as this relay established a locking circuit for itself from grounded battery through its winding, front contact and right-hand armature, resistance 211, test conductor 204, wiper 123, resistance 128 and sequence switch spring 129 to ground. Due to the closure of this circuit the potential on the terminal of conductor 204 is reduced to guard the trunk selected by switch 104 against other selector switches. Relay 207 remains also energized when sequence switch 200 leaves its first position, a circuit being closed from grounded bat tery, through the winding of relay 207, conductor 206, sequence switch spring 212 (positions 1 to 6), front contact and armature of relay 207 the top contacts of sequence switch spring 205, conductor 202, wiper 121, the right-hand bottom contact of sequence switch spring 127, and the front contact and armature of relay 124 to ground.

In position 6 of sequence switch 200, a circuit is closed for elevating-magnet 302 of connector 301 from grounded battery 303 through the winding of magnet 302, conductor 304, sequence switch spring 212, front contact and right-hand armature of relay 207, top contacts of sequence switch spring 205, trunk conductor 202, wiper 121, the right-hand bottom contact of sequence switch spring 127, and front contact and left-hand armature of relay 124 to ground. The elevating magnet 302 attracts its armature 305 and presses thereby brush rod 306 against roller 307, which is constantly rotating in the direction indicated by an arrow. The line wipers 308 and 309 and test wiper 310, and the interrupter brushes carried by rod 306, are, under the control of roller 307, caused to move in an upward direction. The wipers 308, 309 and 310 are adapted to engage the contacts of a terminal bank 314 in which subscribers lines terminate, and brushes 311, 312 and 313 are adapted to engage an interrupter plate 315.

When brush 311 engages a conducting segment, in response to each step taken by the brush, relay 417 is short-circuited and causes upon its deenergization the stepby-step release of the impulse sending arrangement (not shown) set by the incomlng operator. This short circuit may be traced from ground through the armature and back contact of relay 418, windings of relay 417, resistance 416, righthand contacts of sequence switch spring 415, cord finder brush 409, conductor 412, sequence switch springs 126 and 125, wiper 122, trunk conductor 203, sequence switch springs 215 and 216, conductor 217, conducting segment 316, brush 311, conductor 317, brush 313, conducting segment 318, conductor 319, sequence switch spring 218 (position 5 to 6), conductor 219, and front contact and armature of relay 207 to ground.

After the impulse sending mechanism has returned to normal and the wipers of connector 301 have been moved a number of steps, as determined by the set position of the impulse sending mechanism, a circuit (not shown) is closed for relay 418. Relay 418 attracts its armature and causes sequence switch 400 to move out of position 13 into position 16, sequence switch spring 425 being closed in position 13 of the sequence switch. A circuit is now closed from ground through sequence switch spring 426, cord finder brush 408, conductor 411, sequence switch spring 117 and the power magnet of sequence switch 100 to grounded battery, and this sequence switch is moved into its fourteenth position. Sequence switch 100 is driven out of position 14 into position 16 by a circuit from ground through sequence switch spring 129 (bottom), armature and front contact of relay 116, sequence switch spring130, and the magnet of the sequence switch to grounded battery. When sequence switch 100 leaves its position 13, the locking circuit of relay 124 is opened at sequence switch spring 126, and relay 124 in turn opens the energizing circuit of the elevating magnet of connector 301, the circuit of the latter being open also at sequence switch spring 127. The circuit of relay 405 is also opened at 120. This relay deenergizes and drives sequence switch 400 into its normal position, the circuit being closed from ground through the armature and back contact of relay 405, spring 406 and magnet of sequence switch 400 to grounded battery. When sequence switch 400 leaves its position 16, which happens after sequence switch 200 has moved out of position 7, the operators sending device and cord finder 401 are restored to normal.

Upon the deenergization of relay 124 and the opening of spring 127 in position 14 of sequence switch 100, relay 207 becomes deenergized and closes a circuit from ground through its left-hand armature and back contact, sequence switch spring 208 ( positions 6 and 2 to 10), and the power magnet of sequence switch 200 to grounded battery. Sequence switch 200 is moved into position 7. In this position relay 207 is again energized by a circuit closed from the plus pole of grounded battery through the winding of relay 207, conductor 206, sequence switch spring 205 (positions 1, 7 to 7-; and

1 to 7 1*, 16), conductor 202, wiper 121, the left-hand contact of sequence switch spring 127, upper back contact of relay 135, and the secondary winding of repeating coil 113 to the minus pole of battery 136. The energization of relay 207 causes sequence switch 200 to move into position 8, the circuit being closed through theleft-hand armature and front contact of relay 207 and the right-hand contacts of sequence switch spring 208.

Due to the denergization of magnet 302, the wipers 308-310 are arrested on the contacts inwhich the-called subscribers line terminates. The brush rod 306 with wipers 308310 is maintained in its advanced position by a spring-pressed pawl 324' adapted to engage openings in rod 306.

If the called substation line is idle, 'i. e., if full battery potential exists on test terminal 325, test relay 201 becomes energized, a circuit being established from grounded battery 326, through the winding of cut-off relay 327, test conductor 328, terminal 325, wiper 310, conductor 329, sequence switch spring 225, low and high resistance windings of marginal test relay 201, and the bottom contacts of sequence switch spring 226 to ground.

Relay 201 closes-a locking circuit for itself from ground through its upper armature,

front contact and low resistance winding, and sequence switch spring 225 to grounded battery 326, the high resistance winding of relay 301 being short-circuited upon the closure of this circuit. The closure of this locking circuit reduces the potential on the multiples of test terminal 325 so as to prevent another test relay 201 from becoming energized and thereby rendering the line of subscriber B inaccessible to other inconr.

ing calls. Relay 201 belng energized, a clrcult' is closed from ground through lower armature and front contact of relay 201, conductor 227, sequence switch spring 210 (positions 8, 14) and power magnet of sequence switch 200 to grounded battery. Sequence switch 200 moves out of position 8 into position 16.

\Vhen sequence switch 100 came into position 16 a circuit was closed from grounded battery 137, through'sequence switch spring 138, winding of relays139 and 135, sequence switch spring 140, conductor 141, and front contact and armature of relay 111 to ground. Relay 135 becomes energized; relay 139 however, remains deenergized, its winding being shunted through its armature and back contact, and the armature and back contact of ringing relay 142. When sequence switch 200 comes into position 16, ringing current is applied to the called subscribers line from ground through upper armature and front contact of relay 135, left-hand contact of sequence switch spring 127, the talking conductors (indicated in heavy lines), the bell at the subscribers station B, sequence switch spring 143, bottom armature and front contact of relay 135, sequence switch spring 144, winding of ringing relay 142 tery 137 through sequence switch spring 138, Y

winding, armature and front contact of relay 139, sequence switch spring 140, conductor 141, and front contact and armature of relay 111 to ground. Supervisory relay 146 became also energized upon the closure of the talking circuit at the called subscribers station after relay 135 released its armatures. The circuit for relay 146 leads from the plus pole of battery 136 through the secondary winding of repeating coil 113, the talking circuit, winding of relay 146, and the secondary winding of the repeating coil to the minus pole of battery 147. A circuit is now closed from ground through the armature and front contact of relay 111, front contact and armature of relay 146, and winding of relay 112 to grounded battery. Upon the energization of relay 112, the circuit of re-' lays 114 and 111 is opened but-relay 111 is to the deenergization of relay 11% supervisory lamp 115 is extinguished.

After the conversation is finished and the called subscriber hangs up his receiver, relay 146 becomes deenergized and deenergizes in turn relay 112. Upon the release of the armature of relay 112, the winding of relay 111 is again included in its original energizing circuit, and relay 11% thereby causes again the lighting of lamp 115. The operator controlling the cord circuit 101 pulls plug 102 out of ack 103, causing thereby relays 109, 11a and 111 to release. Relay 111, upon deenergization, opens the circuit of relay 116, which by retracting its armature closes a circuit from ground through sequence switch spring 129, armature and back contact of relay 116, and winding of relay 150, which is slow to energize, to groundedbattery. Relay 150 closes then a circuit over sequence switch spring 130, and sequence switch 100 is moved over its 18th into its first position. In positions 17 and 18 of the sequence switch, selector 10 i is restored in the well-known manner.

When the brush 123 of selector 10st disengages the terminal of conductor 204:, relay 209 becomes det nergized and closes a circuit from ground over its left-hand armature and back contact, sequence switch spring 210, and- )ower ma net of se uence switch 200: to-

grounded battery, and this sequence-switch is moved into its 18th position. hen sequence switch 200 leaves p0sition.16,-the circuit of test relay 201 is opened at 225, and this relay becomes denergized. Further, a circuit is closed from grounded battery 303, through the winding of release magnet 330, conductor 331, and sequence switch spring: 218 to ground. Magnet 330 attracts its armature 332, causing thereby pawl 32a to disengage brush rod 306, and presses the brush rod against roller 333 constantly rotating in a counter-clockwise direction. 7 The roller 333 moves the brush rod in a downward. direction, and when it reaches its normalposition, a circuit is closed from grounded bate tery through the power magnet of sequence switch 200, sequence switch sprin 210,.con.- ductor 3341, conducting sepgnent 3 10ofinterrupter 315, brush 312, conductor 317, brush 313, conducting segment 313, conductor 319, and sequence switch spring 218 to ground. Sequence switch 200 moves out of position 18 into position 1, and opens the en-v ergizing circuit of magnet 330.

The apparatus is now released. to normal and ready for use in the building up of another connection.

If the called subscriber is busy, the poten. ial on test terminal 325 is reduced so as prevent the energization of test relay 201 in position 8 of sequence switch 200, A circuit is thereforeclosed from grounded battery through the winding of relay 207, conductor 200, left-hand topconta ct of sequence switch spring 215, right-hand bottom contact of sequence switch spring 216, and upper armature and back contact of test relay 201 to ground. Relay 207 becomes energized and closes a circuit from ground through its left-hand armature and front contact,'righthand contacts of sequence switch spring 208, and power magnet of sequence switch 200 to grounded battery, for moving sequence switch into position 14:. Release magnet 330- is now energized, a circuit being closed from grounded battery 303 through the winding of magnet 330, conductor 331, sequence switch spring 230, and back contact and upper armature of relay 2.01, to ground. Under the control of magnet 330, connector switch 301 is returned to its normal position. A circuit is now closed fromgrounded battery through the power magnet of sequence switch 200, left-hand bottom contact of sequence switch spring 210, conductor 3341, conducting segment 3&0 ofinterrupter 315, brush 312, conductor 317-, brush 313, conducting segment 318, conductor 319, and left handv bottom contact. of sequence switch spring 2118, to ground. Sequence switch 200 moves into position 17, and a. busy tone is applied to the callingsubscribers line from 235 through. the top contacts 01 sequence switch spring 226.

The apparatus employedv in the building up of the connection is restored in thesame manner as above described when considering the severing of a. connection extended to an 7 idle subscriber.

In order to insure the seizure of the called line irrespective of. the electrical conditions existing on the same, prior to the sending out of impulses, the incoming operator. depresses.- the nortest key 402' and causes thereby the energization. of relay 4:30, the

circuit being from grounded battery 131 switch 200 reaches position 8, and sequence switch. 100 position 13. A circuit is now closed from ground through the bottom Con-- tacts of sequence switch spring 226, high re sistance winding of test relay 201, sequence switch spring 2410,. conductor 21-1, armature and back contact of relay 207, sequence switch springs 216 and 215, conductor 203,

wiper 122, sequence switch springs 1-255and.

126, conductor n2, cord finder brush 409, sequence switch spring 4:15 and armature and front contact of relay no to ground. The high resistance winding of relay 201 being thus short-circuited upon the closure of the test circuit, this relay becomes energized even in case the test potential on terminal 325 is reduced.

The establishment and the release of the connection proceeds in the same manner as above described.

I t will be seen therefore, that in case the incoming operator depresses the no test key 4.02, test relay 201 becomes effective and performs all its functions (rendering busy of the called line, cooperation in the control of connector 401, etc), irrespective of the electrical condition existing on the called line.

\Vhat is claimed is: 7

1. In a telephone system, a plurality of? lines, a plurality of other lines, means for testing said other lines, means for extending one of said lines, a connector controllable over said extended line for selecting one of said other lines, and means also controllable over said extended line for rendering said testing means ineffective.

2. In a telephone system, a plurality of lines, a plurality of other lines, means for extending one of said lines, a connector controllable over said extended line for selecting one of said other lines, means actuated under a predetermined electrical condition of the selected other line for controlling said connector, and means controllable over said extended line for causing said last mentioned means to operate irrespective of said electrical condition.

3. In a telephone system, a plurality of lines, a plurality of other lines, means comprising selector switches for extending one of said lines, a connector controllable over said extended line to select one of said other lines, means cooperating in the selecting operation of said connector under a predetermined electrical condition of said other line, and means controllable over said extended line for rendering said last mentioned means eliective irrespective of said electrical condition.

In a telephone system, a plurality of lines. a plurality of other lines, selector switches for extending one of said lines, a connector controllable over said extended line for selecting one of said other lines, means for testing said other lines and for cooperating in the control of the selective operation of said connector, and means also controllable over said extended line for rendering said last mentioned means inefi'ective as to its testing function.

In a telephone system, a plurality of lines, a connector switch for selecting called lines, selector switches for extending a calling line to said connector, means for testing the selected called line, and means controllable ov r said calling line for rendering said testing means inefi ective prior to the operation of said connector. V

' 6. In a telephone system, a plurality of lines, a connector, selector switches for connecting a calling line to said connector, means controllable over said extended calling line for operating said connector to seize a called line, a test relay associated with said connector and adapted to operate under a certain electrical condition of the selected called line, and means controllable through said extended calling line prior to the seizure of the called line for permitting the. operation of said test relay irrespective of said electrical condition.

7. In a telephone system, a plurality of incoming lines, a plurality of outgoing lines, a connector adapted to connect a calling incoming line to an outgoing line under the control of current impulses sent over said incoming line, a test relay having two windings for testing a selected outgoing line, means for operating said test relay under a predetermined electrical condition of the selected outgoing line, and means controlled over said incoming line prior to the operation of said connector for shunting one of said windings to permit the operation of the test relay irrespective of the electrical condi tion of said outgoing line.

8. In a telephone system, a plurality of lines, operators positions, means for extending a calling line to an operators position, trunk lines, selector switches for extending a calling line through any one of said trunk lines, a connector switch, a test relay associated with said connector and having a high and a low resistance winding, means controllable from said operators position through said extended calling line to operate said connector, and means also controllable from said operators position through said calling line for shunting the high resistance winding of said test relay prior to the opera tion of said connector.

9. In a telephone system, a plurality of incoming lines, a plurality of outgoing lines, means for connecting a calling line to one end of a trunk line, a connector at the other end of said trunk line, means controllable over said trunk line for operating said conmotor to seize a called line, a test relay adapted to be energized over the called line upon the seizure of same, a. high and a low resistance winding for said test relay, and means controllable over said trunk line for shunting said high resistance winding prior to the seizure of the called line.

10. In a telephone system, a plurality of incoming lines, a plurality of outgoing lines,

selector switches for extending a calling incoming l1ne,a connector for connectin an extended lncoming line to a called outgoing line, means operative under a predetermined lines, and Ineanscontrollable over said incoming line for rendering said first mentioned means effective priorto the operation of said connector and irrespective of said electrical condition.

In Witness whereof, I hereunto subscribe my name this 3rd day of. June, A. D. 1915,. HENRY PETER CLAUSEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

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