US2395798A - Traffic control system - Google Patents

Description

March 5, 1946. j "J. BAUMFALK 2,395,798-

TRAFFIC CONTROL SYSTEM Filed Dec. 17,1942 ssheets-sneeti f 2 Q5 lNVENTOR q, 'J. BAU MLK 'Ma'rch 5, 1946. J. BAUMFALK TRAFFIC CONTROL SYSTEM Filed Dec. 17, 1942 5 Sheets-Sheet 2 INVENR'JR J BAUM/ZL/f ATTORNEY .1. BAUMFALK 2,395,798

TRAFFIC CONTROL SYSTEM March 5, 1946.

3 Sheets-Sheet 3 Filed Dec. 1'7, 1942 v U. R m 0 0 TM T MM M N V v 7 III a m L383 v 6 8558 J 33 8.3 V

m at

Patented Mar. 5, 1946 'Eelephone Laboratories, Incorporated, New

Yo'rk, N. Y.,a corporation of New Yorlr Application December 17, 1942, SerialNo. 469,299-

12 Claims.

This invention relates to telephone systems and has for its object the control of telephone traflic loads in emergencies.

In thebaseof emergencies, such as attack by enemy forces, it is apparent that it might be desirable to deny service to private subscribers.

in order that the central o-fficeequipment be adequate to handle military and civilian defense traffic. For this purpose 'it has been suggested that the telephone lines may be divided into several groups or classes and manual keys provided by which service may be cut off from the diiferent classes of lines according to the requirements of the emergency.

.It is the object ofthe present invention to provide means to control the removalof classes oflines from service and the, restoration of them to service under centralized remote control.

To guard against unauthorized persons interfering with service, this centralized control means is responsive only to a series of, operations not likely to be performed accidentally and a code is employed which differs from any used in service.

More specifically, means is provided for removing the classes of lines. from service responsive to a predetermined number of identical, successively dial-ed digits. and for restoring the lines to service responsive to a similar operation but employing a difierent digit. r

In addition means is provided, responsive to the dialing of the same digit a predetermined plurality of times, for obtaining an indication of the busy condition of the equipment used by subscribers in originating connections.

Means. is also provided for, ascertaining whether any group of lines hasbeen removed from service and which group or groups. 7

These and other features of the invention will be more clearly understood from a consideration of the following description in connection with the drawings in which;

Figs. 1 and 2 show the remote control equipment; and

Fig. 3 shows both the line load control equipment and the means for checking the busy condition of the call originating switches.

When it becomes desirable to employ line load control in a particular office, a study will be made of the subscribers lines terminating in that oflice for the purpose of dividing the lines into classes in accordance with their importance in the case of an emergency. Lines such as police station lines, fire station lines, hospital lines, etc., will all circumstances. The division oi the remaining lines into classes B and C will be on atrafno basis so that the removal ofv either-class will relievethe traffic load in allpparts of they Qffioe.

The line load control circuit shown in detailiin Fig. 3. is that belonging to class C7,. while t'he'load control circuit for the class B- lines is indicated by the box 355). J

The subscribers line I 00 andthe connecting link iii! are to be taken; as illustrative only of any desirable means of connecting an. authorized oflicial line with the remote control equip ment shown. This equipment may be seizedi'as indicated over a selector terminal bank or, may be reached through an; operatorsposition or over an interoiiice trunk in which case suitable terminating jacks would be provided. 7

When a connection has been established with the remote control equipment, a circuit is completed from battery through the upper winding of relay I92 over the incoming connection to the calling dial and back to ground through the, lower winding of relay H12. Relay Hl2 in operating closes an obvious circuit for relay Ill-3 which is slow to release. Relay IE3 at contact 41 connects ground to the sleeve conductor I20 therebymarlring the circuit busy and holding the switches over which the connection was, extended to the remote control circuit. At contact 2-, relay H13 completes a circuit over contact 8 of relay H2: to the winding of relay H3 and battery. Relay 3 operates and looks over contact 5 tov'ground at contact 3 of relay E03 independentof; relay H2. Relay I I3 connects ground to conductors 121. I22 and 23 to. provide lockingcircuits' to .beqdce scribed hereinafter. Ground on conductor P22 also extends over; normal contact 2H of switch 2m to the winding of relay I04 and battery, -op-.- erating relay Hi4.

Switches 2m and 22B are rotary switches, s'witchZlll' including brush 2H and off-normal contacts 215 to Zll. The switch. is. rotated by stepping magnet 2M and restored to normal by release magnetv 2J3; Switch220 includes. brushes 22! and 222, off-normal contacts 225; and 226;, is advanced by stepping magnet 2-24. and is restored by release magnet 223.

When the authorized person or .ofiicial located at substation I00 next operates his dial, relay )2 falls. back, closing a circuit from ground over the back contact of relay I02, contact 6 of relay H3, lower contact of relay 10.4, contact 3 of relay E05, winding of magnet 2M to :battery. The first step of switch 2H1 opens contact 2|! and closes input in class A and will receive service under contacts M5 and H6. Contact 2|! opens the previously traced circuit for relay I04 but relay I04 is slow to release and before relay I04 can open its contacts, contact 2 I6 closes a circuit for relay I04 in parallel with magnet 2I4. Because of its slow-to-release character, relay I04 remains operated between the pulses which operate magnet 2I4 to advance switch 2 I0.

In order to render the remote control equipment efiective, a predetermined digit, for example, the digit 2 must be dialed a plurality of times. At the end of the first digit, brush 2II will rest on contact 252 and they circuit of relay I04 will be opened long enough to permit that relay to release. When relay I04 closes its upper contact, a circuit is completed from ground over contact I of relay I03, upper contact of relay I04, contact I of relay I06, brush 2, terminal 252, contact I of relay 2I8 to the winding of relay 232 and battery. Relay 232 looks over contact 2 to ground on conductor I2I. Relay 232 also closes a, circuit from battery through winding of relay I06, contact I of relay I01, contact equipment in the ofiice. Relay I08 operates in parallel with relay 244, the circuit extending as above traced from ground to contact 4 of relay I09 and thence over contact I of relay I05 to the winding of relay I08 and battery. Relay I03 looks over contact I, to ground on conductor I23.

Referring to Fig. 3, substation 3I0 represents any one of the subscribers lines in the ofilce at which the remote control equipment is located. When a call is originated on line 3I0, line relay 3I2 is operated. Relay 3I2 connects battery through resistance 3I3 in parallel with battery through cut-01f relay 3 to the sleeve contact 3 of relay 232, contact 9 of relay 2I8, to ground on conductor I2I. Relay I06 operates and closes a holding circuit for itself over contact I of relay I01, contact 2 of relay M6, back contact of relay I04, contact I of relay I03 "to ground. At contact 3, relay I06 closes a circuit from ground through the winding of relay 2E8, to battery. Relay 2I8 operates and looks over its contacts 8 to grounded conductor I 2| Relay 2 I8 opens the original operating circuit for relay I06, closes a circuit from ground on its contacts I6, contact 4 of relay I06, oil-normal contacts 2I5 to the winding of releasemagnet 2I3 and battery, thereby restoring switch 2I0 to normal, opening contacts 2I5 and 2I6, and reclosing contact 2I1.

The dial is now reoperated to again transmit the digit 2. Relay I02 responds to the dial pulses as before and again operates relay I04 which in turn opens the holding circuit of relay I06, permitting that relay to release. Brush 2I I is advanced into contact with terminal 252 in the manner previously described. At the end of the digit, relay I02 remains operated, relay I04 releases and the circuit previously traced to the brush 2 is closed. However, since relay 2I8 is now operated, the circuit extends over terminal 252, contact I4 of relay 2I8, contact 5 of relay 232, to the winding of relay I01 and battery. Relay I01 operates and locks over its contact 3, back contact of relay I04 to ground at contact I of relay I03. At contact 2 relay I01 closes an obvious circuit for relay I06 which now operates. At contact 4 relay I01 closes acircuit for rotary magnet 224 of switch 220 advancing the switch one step to close contacts, 225 and 226. Since relay 2I8 is still operated, the operation of relay I 06 closes the previously traced circuit for release magnet 2I3 and switch 2 I0 is restored to normal.

When the dial is operated to transmit the next digit 2, the holding circuit for relay I 01-is opened and that relay releases in turn releasing relay I06 and magnet 224.

Following each dialing of the digit 2, relay I01 is operated and switch 220 advanced one step. When the switch 220 has advanced a predetermined number of steps, for example, six steps, brush 222 engages terminal 221 and a circult is closed from ground at contact 1 of relai 2I8, brush 222, terminal 221, contact 4 of relay I09, contact I of relay 232 to the winding of relay 244 and battery. Relay 244 controls switch 200 to test the condition of the cell o ig at g individual to the line in the various line finders which have access to the line, to mark the line as calling. In addition, line relay 3I2 connects ground to the winding of group relay 303. Relay 303 is common to the group of lines including line 3I0 and operates in response to the initiation of a call on any line of this group. When operated, relay 303 connects ground to the start circuit of a group of line finders of which line finder 304 is one. The line finder 304 operates to find the calling line and, when the line is found, cut-oil relay 3 is operated and locked to the sleeve conductor under the control of the line finder circuit. The operation of cut-off relay 3 releases line relay 3| 2, in turn releasing group relay 303 unless some other line in the group is also calling. I

As each finder of the group of finders is taken for use it extends the start circuit to the next finder and subsequent calls in the group of lines including line ,3I0 or in any other group to which these finders have access will be served by line finders in the group including line finder 304 in rotation. Each finder of the group, when idle, connects battery to the winding of relay 302 so that relay 302 remains operated as long as there is one idle line finder in the group. When the last finder has been taken for use, relay 302 releases operating relay 30I which thereupon connects ground to conductor 330 lighting lamp 300. Conductor 330 is also connected to a terminal of switch 200.

When it is decided to provide emergency load control in an office the back contact of a relay, such as relay 3I5, is inserted in the circuits of all group relays such as relay 303 for class B and C lines. The function of relay-3I5 will be discussed hereinafter. It is to be understood that the arrangement is equally applicable to offices employing other types of ,line findersor to those employing line switches. In the latter case the contacts of the relay like relay 3I5 will be inserted in the battery supply circuit of the line switches. The line finders serving lines in class A will not be altered. Line finder 304 is assumed to be of the type disclosed in Patent 1,799,654 to R. L Stokely, April 7, 1931.

, With relay 244 operated, a circuit is closed from tone source 240, which may be the source of dial tone, over contact I of relay 24I, contact I of relay 242, contact 1 of relay 244, contact 4 of relay I05 to the tip conductor of the incoming circuit, thereby transmitting a preliminary or warning tone to the substation I00 indicating that the circuit is ready to test the condition of the line finder groups. Relay 244 also closes a circuit from ground at its contact 9, contact 3 of relay 243 to the winding of relay 245 and battery.

A circuit is also closed from battery through the winding of relay 246, contact 5 of relay 244 to brushes 20I and 202 of switch 200. Direct ground is connected to the first six terminals of the arc served by brush 202 and, therefore, in the first six positions of brush 202, the circuit of relay 24B is completed to ground and relay 240 operates. With relays 245 and 24B operated, a circuit is closed from battery through the winding of relay 243, contact 5 ofrelay 245, front contact of relay 245, contact of relay .244 to ground. Relay 243 operates in this circuit, opening the circuit of relay 245 which releases slowly, in turn opening the circuit of relay 243, which likewise releases slowly. During the time that relays 243 and. 245 are operated, a circuit is closed from battery through the winding of stepping magnet 201, contact 2 of relay 245, contact 2 of relay 243 to ground at contact 9 of relay'244. Switch 200 is, therefore, advanced over its first six positions under the control of relays 243 and 245.

When brush 200 reaches position 5, a circuit is closed from ground over brush 206 in position 5 to the winding of relay 242 and battery. Relay'242 locks over its contact 2, contact 2 of relay 244, to ground over brush 204'. At contact I, relay 242 opens the tone circuit to terminate the preliminary tone.

When'switch 200 reaches position I, the circuit of relay 246 is open and relay 246 releases and closes a circuit from battery through the winding of relay 208, contact 4' of relay 244, back contact of stepping magnet 201, back'contact of relay 246 to ground at contact 8 of relay 244. Relay 208 operates slowly in this circuit and, when operated, closes a circuit from battery through the winding of magnet 20?, front contact of relay' 208, back contact of relay 246 to ground-at contact 8 of relay 244. Magnet 20? ance operates, opening the circuit of relay 208 which releases, in turn opening the magnet circuit. Magnet 20'! releases, stepping switch 200 to position 8. While switch 200 was in position 'I, a circuit was closed from ground over brush 206 v in position I to the winding of relay 24I andbattery. Relay 24! operates, looks over its contact 3 to ground in parallel with relay 242 and prepares a new tone circuit.

Conductor 330, individual to the group of lines containing line 3H1 as indicated in Fig. 3, is connected to the terminal of brush 202 in position 5. If this group of line finders still contains one or more idle finders, no ground will be connected to conductor 33!! and switch 200 will be advanced to position 9 under the control of relay 208 as described for the advance to position8. Assuming, however, that the entire group of line finders is busy, so that ground is connected to conductor 330, a circuit will beclosedfrom round on conductor 330 over brush 202, contact 5 of relay 244 through the winding of relay 240 to battery. Relay 246 operates, opening the circuit of relay 208 and closing a circuit from ground, at contact 8- of relay 244, front contact of relay 246, contact 3 of relay 245 to the winding of relay 243 and battery. As described in the advance of switch 200 to position 5, relays 243 and 245 close a circuit for stepping magnet 20? which steps switch 200 to position-0.

and the functions above described will be repeated as long as the remote control circuit is held. At any time after the ofiicial hears-the prelim 'inary tone signal, he may disconnect, thereby re leasing relay I02 followed by relays I03, H3, I08, H8, 232, 244, 24!, 242 and 245. Since relay I03 is slow to release, relay I02 in releasing closes a circuit from ground at its back contact, over contact 6 of relay II3, contact 5 of relay 244 Winding of relay H2 to battery through resist- II4. Relay II2 operates in this circuit and locks over its contact 4 to ground at contact 2 of relay I00, and contact 5 of relay I09. The operating circuit of relay I I2 is opened when relay H3 releases. ,Relay H2, in operating, closes a circuit from ground over contact 5 of relay II I, contact 5 of relay II2, off-normal contact 225 of switch 220 to battery through the winding of release magnet 223 thereby restoring switch 22 0 to normal.

Relay H2, in operating, starts the measurement of a time interval within which the re mote control equipment remains in readiness :for

further operation. To this end, relay II2 closes a circuit from ground over interrupter I24, contact l of relay II2, contact 5 of relay I03, winding of relay H0 and battery. Relay III] operates at each closure of the interrupter contact. At the first closure of the front contact of relay H0, anobvious circuit is closed for relay III which looks over its contact 2 to ground at contact 3'of relay H2. When the interrupter I24 opens its contact, relay H0 releases closing a circuit from ground over its back contact, contact I of relay III, contact 2 of relay H2 tothe winding of stepping magnet 224 of switch 220.

Switch 220- is therefore stepped under the concircuit to be selected, for example, 30 seconds.

When brush 22! reaches terminal 228 a circuit is closed from ground over contact 3 of relay III, brush 22I, terminal 228 to battery through resistance H4 in shunt of the winding of relay II2,-causing relay II2 to release. Relay H2 at contact 3 opens one locking circuit for relay III but relay III remains operated to ground over oil-normal contact 220. With relay II 2- released,

a circuit is closed from ground at contact 4 of.

relay Ill. contact 0 of relay H2, off-normal contact 225, winding of release m'agnet'223 to 7 244, to ground over brush-1203 or brush204.

The speed'of interrupter I24 and a that he previously dialed the digit 2. 'The digits used for particular functions have been selected arbitrarily, but others mightoe employed by changing the connections of relays 232 to 231 at the contacts of relay 218. The reselection of the remote control circuit operates relays 1112 and 103. Since relay 112 is held operated, relay 1 13 cannot operate, but a circuit is closed from' ground over contact 2 of relay 1113, contact 1 of relay 112, contact 8 of-relay 113 to battery through the winding of relay 1119.- Relay 1B9 operates in this circuit and looks over its contact 1, contact f relay 232 to ground at con tact 3 of relay 133. 'When relay 139 operates, it' opens the locking circuit for relay 112 and that relay releases. With relay 112 released, relay 113 is permitted to reoperate. 109 operated, relays 234 to 231 are rendered effective. Prior to the operation of relay 133 only relays 232 and 233 are effective.

Assuming that it is desired to remove from service the class 0 lines which include line 3111;

the official will dial the digit 5 at least seven times; Switch 210 is advanced in the manner previously described until it reaches position 5. When relay 1112 remains operated and relay 1114 released following the first digit, the circuit previously traced is completed from ground at the contact of relay 123 to brush;2l1 and over the fifth contact of brush 211, contact 5 of relay 218 to the winding of relay 235 and battery. Relay 235 operates and looks over its contact 2 to ground on conductor 121. With relay 235 operated, relay 106 is operated, the circuit extending over contact 3 of relay 235 insteadof over con- With relay tact 3 of relay 232. Relay 133 operates, in turn operating relay 218 and restoringswitch 210 to normal. When brush 211 is advanced to position 5 in response to the second digit, relay 101 is operated, in turn operating relay 1136 and stepping switch 221]. When switch 228 has been advanced to position 1, a circuit is closed from ground at contact 1 of relay 218,brush 222, terminal 221, contact 3 of relay11l9, contact '1 of relay 235 to the winding of relay 321 in the load call by any line in'class C.

In addition, relay 315 closes a circuit from ground through lamp 314, resistance 318, winding of relay 311fto battery, lighting the lamp to indicate which class of line has been removed from service. Relay 311 operates in this circuit and closes an obvious circuit for relay 323. Relay 323 at its contact 4 lights lamp 331 and at contacts 1 and 2 closes a circuit for operating buzzer 325 to inform the local maintenance man that a portion of the lines has beenremoved from service. In addition, relay 323 closes a circuit from battery through the windingof relay 319,

aaea'zes right contact of relay 321, contact 5 of relay 323, normal contact of key 328 to ground at the back contact of relay 1 11 in the remote control circuit. Relay 31s operates in-this circuit locking over its'contact 3 and contact 5 of relay 323 to ground at the contact of relay 111, independent of relay 321. At its contact 2 relay 319 closes a locking circuit for relay 315 thereby locking the class C lines out of service after the remote control circuit has been released. At contact 4, relay 319 closes a circuit for relay 115 in the remote control circuit. With relay 113 operated a circuit is closed from the code 2 ringing source over conduo-tor 129, contact 4 of relay I16, contact 4 of relay 235, condenser 241, contact 4 of relay 105 to the tip conductor of the incoming circuit to inform the official that the classC lines have been removed from service. r

The ofiicial now disconnects. He may permit the remote control circuit to restore to normal as previously described; he may reseize the remote control circuit and again dial a series of 2s to detemine the efiect of the removal of the class C lines in relieving the congestion, or he may dial a series of 4s to remove the class B lines from service. The operation in either case is substantially as above described. Dialing a series of 4s results in the operation of relay 234 and relay 234 causes'the operation of, a relay similar to relay 321 in the class B line load control circuit351l, which in turn opens the line finder group relay circuits for the class B lines and brings about the operation of relay 118. Relay 118 closes a tone circuit from the code 1 ringing source to indicate that the class B load control circuit has functioned. Dialing a series of 2s results in the operation of relay 232 as previously described. Relay 232 in operating opens the locking circuit of relay 109 and that relay releases to reclose the operating circuit of relay 244. I

When the emergency is over and it is desired to restore the class B and class C lines to service, the ofiicial will again seize the remote control circuit and dial a series of 2s in order to condition the circuit. He will then disconnect and re- 7 will dial a series of 6s or aseries of '1s in order to restore the class B or class C lines respectively.

Dialinga series of 7s will cause the operation of relay 231 at the end of the first digit. When the series has been completed, a circuit is closed from ground at contact 1 of relay 218, brush 222, terminal 221, contact 3 of relay 1B9, contact 1 of relay 231 to the winding of relay 1 11 and battery. Relay 1 11 operates in this circuit and opens the locking circuit for relay 319 permitting that relay to release and in turn release relay 315 and the other similar relays associated with the class C lines.

Dialing a series of its results in the operation of relays 236 and 113 to restore the class B lines to service.

If the ofiicial wishes to determine whether any lines have been removed from service and which relay 233 operated, the advance of switch 221] in response to the subsequent digits places brush 222 in engagement with terminal 221, completing a circuit from ground over contact] of relay 2I8, brush ZZZ-{terminal 22-1, contact I of relay 233, winding of relay H and battery. Assuming that only the classG lines have been removed from service, relay H6 will be operated alone and the operation of relay H5 will close a tone circuit from the tip conductor of the incoming connection, contact 4 of relay I05, condenser 241, contact 4 or relay 233, contact'4 of relay H5, contact 2 of relay I I6, contact 3 of relay H8 to conductor I29 and the code: 2 ringing source. Therefore, the oflicial will hear the 2-ringcode and will be informed that the .class- C lines are out of service.

If only theclass B lines have been removed from service so that only relay H8 has been onerated, the tonecircuit extends as above traced to contact 4 of relayl I5 and thence over contact 3 of relay H6 and contact 2 of relay IIB to conductor I28, and the code I ringing generator. If no lines have been removed from service, the tone circuit extends from contact 4 of relay H5 over contact 3 of relay H6, contact I of relay H8, contact 5 of relay H5, to conductor I21 which extends to a source of steady ringing current.

Whenever relay H5 is operated, a circuit is closed from battery through the winding'of relay I25 over contact I of relay H5 to conductor I23, to which ground is connected at the rate of sixty impulses per minute. If both class B and class C lines have been removed from service, the tone circuit extendsfrom contact 4 of, relay H5,

-contact 2 of relay I I0, contact 4 of relay I I8,- over the front contact ofrelay I25 to conductor I21.

Therefore, steady ringing current, interrupted at a rate of sixty interruptions perminute, is connected to the tone circuit as an indication that both the class B and class C lines have been removed from service.

The operation of relay I I5 also serves to silence the alarm in the line load control circuit. Assuming that the class C lines have been removed from service so that relay HIS is operated, relay I I 5 in operating closes a-circuit from ground over contact 2 of relay H5, contact I of relay H6, upper normal contact of key 328, upper winding of relay 324 to battery Relay 324 operates in this circuit and looks over contactsor key 328, front contact of relay 324 to ground at contact 3 of relay 323. At its lower contact, relay 324 opens the circuit of buzzer 325. A similar arrangement is provided for silencing the alarm associated with the class B load control circuit 350.

To guard against the accidental selection and operation of theload control circuit, the remote control circuit is so arranged that'if, after operating one of the relays 232 to 231, a difierentdigit is dialed, no circuitis completed for relay I01 since the circuit of that relay extends over the contact or the operated relay to the terminal of brush 2I I over which the relay was originally'op Grated. Furthermore; if such a digit is dialed, when relay I04 releases, a circuit i's'closed for relay I05. Assuming, for example, that relay 232 had been operated and that subsequently the digit 3 was dialed, when relay I04 releases following the dialing of the digit 3, a circuit-will be closed from ground, contact I of relay I03, back contact of relay I04, contact I of relay'I05', brush 2H in position 3, contact I2 of relay 2I8,'contact Ii of relay 233, to the winding of relay I05 and battery. Relay I05 at its contact 2 closes an obvious circuit for relay I08 which looks under the control of relay I I3. At contact 3 relay I05 opens the operating circuit for stepping magnet 2I4, preventing the operation ofswitch 2I-0 in re sponse to subsequent digits and atcontact 4 opens the tone circuit. Relay I05 releases when the official disconnects, releasing relays I02 and I03 to'restore the remote con trol circuit to normal.

It is also possible to remove the lines of class C from service under local manual control by momentarily operating key 321, thereby closing a circuit for relay 32I which functions as previously described, ,The lines may also be restored to service manually by momentarily operating key BIG thereby releasing'relay 1H5.v A separate key, like key SIB, is provided for each relay 315 so thateach relay must be released: separately. When all of the relays 3I5 havebeen released, relay 3II releases,'in turn releasing the remainder of the load control relays.

If it should be desirable to remove lines within a class of lines from service, thismay' be accomplished by operating key 328. Key 320 at its out-- or lower alternate contacts connectsrrelay 3I9 to ground at the back contact of relay H1, and; at its inner lower alternate'contacts connects relay 323130 a local ground. Relays 319 and 323 operate. If now relay 3I5- isoperated by hand, relay 3I5 will lock-to ground at contact 2 of relay, 3I9 and remain operated. The buzzer may be silenced by operating key 326 which connects ground over the upper alternate contacts of key 328 to the lower winding of relay 324 and battery, operating relay 3-24.- i

I-f relay 3I5 is operated falsely and lamp 3I4 is burned? out so thatno alarmis sounded, relay I 3 I 9 will not be operated-and relay 3 I 5- closes a cirsuit from battery through itslower winding and lower contact, over key 3I3, contact I of relay M9 to ground through the winding of relay 320. Relay 3I5 will not lock in this circuit but relay 320 operates, connecting ground to the winding of relay 323, operating relay 323 to sound an alarm.

With relay 244-operated, it the oflicialattempts to dial an additional digit, a circuit will be closed, when relay I02 falls back in response to the first interruption of the extra digit from ground over the back contact of relay I02, contact 6 of relay H3, contact 0 of relay 244 tothe winding of relay H2, resistance H4 and battery. Relay I I2 looks over its contact 4 to ground at contact 2 of relay I-08.- With relay H2 looked, a circuit is closed from battery through the windingof. magnet 2I4 of switch 2I0,- contact 30f relay I05, iront contact of; relay I04,- contact 6- of relay. 244,- contact 4- of relay H2 to ground at contact'Z of relay I08, thereby closing a steady circuit for magnet 2I4 throughout the digitand preventing its response to the dial pulses. If any extra digits are dialed after the remote control circuit has been released and reseized, relay I09 is operated and, when relay I08- operates in parallel with either relay II'I, relay H9 or relay 32I, the circuit for holding magnet 2l4 operated: will extend as previously traced to the front contact of relay I04 and thence over contact 20f relay I09, contact 3' of relay I08, contact-4- of relay" I I2 to ground-at contact 2 of relay I 08- rendering the remote control circuit independent of excess digits.

What is claimed is:

1.In a telephonesystem; subscribers lines divided into groups, switching equipment, aline relay for each of said lines, meansr'esponsive to the 'operation ofthe lirierelay of anyone "of said lines for connecting said line with said switching equipment, meansfor disabling the responsive means pertaining to all of the lines in certain of said groups of lines, a directively operable switch, and means including said switch for operating said disabling means- .7 a r i 2. In a telephone system, subscribers lines divided into groups, switching equipment, a line relay for each of said lines, means responsive to the operation of the line relay of any one of said lines for connecting said, line :with said switching equipment, means for. disconnecting said responsive means from all of the lines in certain of said groups of lines, a directivelyoperable switch, and means including said switch for operating said disconnecting means.

3. In a telephone system, subscribers lines divided into groups, switching equipment, means responsive to the initiation of a call on any one of said lines for connecting said line with said switching equipment, and means for directively disabling the responsive means pertaining to certain of said groups of lines comprising registering means,-means for repeatedly positioning said registering means in response to the dialing of the same digit, and means responsive to a predetermined number of reoperations of said registering means to operate said disabling means.

4. In a telephone systemfsubscribers' lines divided into groups, switching equipment, means responsive to the initiation of a call on any one of said lines for connecting said line with said switching equipment, means for directively disabling the responsive means pertaining to certain of said groups of lines comprising registering means, means for repeatedly positioning said registering means in'response to the dialing of the same digit, means responsive to a predetermined number of reoperations of said registering means to "operate said disabling means, and means to prevent the operation of said disabling means if said registering means is reoperated in respo'nse to a difierent digit. 5. In a telephone system, subscribers lines divided into groups, switching equipment, means responsive to the initiation of a'call on any one of said lines for connecting said line with said switching equipment, means for directively disabling the responsive means pertaining to oer-'- tain or saidgroups of lines comprising register ing 'means'means forrepeatedly positioning said registering means in response to the dialing-of the same digit, means responsive :to a predetermined number iof reoperations of said'registering means to operate said disabling means, and means operated in accordance with the value of said digit to determine" the groups of lines'for which the responsive means shall be disabled.

6. In a telephone system, subscribers linesdivided into groups switching equipment, means responsive to the initiation of a call on anyone of said lines for-connecting said line with said switching equipment, means 'for directively disabling the responsive means pertaining to certain of said groups of lines comprising registering means, means for'repeatedly positioning said registering means in response to the same digit, means responsive to a predetermined number of reoperations of said registering means to operate said disabling means, and means responsive V to a predetermined number of operations of 'said registering. means in response. to a different digit forreleasing said disabling means. 7. In a telephone system,'subscrihers. lines divided-into groups. switching equipment, means responsive tothe initiation of a call on'any one of said lines for connecting said line with said registering means in 'oneof said groups of lines.

switching equipment, means for directively disabling the responsive means pertaining to certain of said groups of lines comprising registering means, means'for repeatedly positioning said registering means in response to the same digit, means responsive to' a predetermined number of reoperations of said registering means to operate said disabling means, means responsive to a predetermined number. of operations of said registering means in response'to' a different digit for releasing said'disabling means, and means operated in accordance with the value of said other digit to determine the groups of. lines for which the responsive means shall be reenabled.

8. In a telephone system, subscribers. lines divided into groups, switching equipment,.connecting means responsive to .the initiation of a call on any one of said lines. for connecting said lines with said switching equipment, said connecting. means also divided into groups, indicating means operated when each one of said groups of connecting means becomes busy, means for determining which of said groups of connecting means are'busy comprising means for successively connecting with "the indicating means of each of said groups of, connecting means, and means responsive to connection with an operated indicating means for generating a pulse of tone.

9. In a telephone system, subscribers lines divided into groups, switching equipment, connecting means responsiveto the initiation of a call on any one of said lines for connecting said lines with said switching equipment, said ,connecting means also divided into groups, indicating means operated when each one of said groups of connecting means becomes busy, means for determining which of said groups of connecting means are busy comprising registering means, means for repeatedly positioning said registering means in response to the same digit, means responsive to a predetermined number of reoperations of said registering means for successively connecting with thefindicating means oiF-each of said groups of connecting means, and means responsive to connection with an operated indicating means for generating a pulse of tone.

10. In a telephone system, subscribers" lines divided into groups, switching equipment, connecting. means responsive to the initiation of a call on any one of'said linesforuconnecting said lines with said switching equipment, said connectingmeans also divided into groups, indicating means operated when each one of'said groups of connecting means becomes busy, means for determining which of said groups of connecting means are busy comprising a'control circuit, means for selecting said ,control' circuit, said control circuit, means for repeatedly positioning said registering means in response to-the same predetermined digit, means responsive to a predetermined number of reoperations of said registering means for successively connecting with the indicating means of each. ofsaid groups .of; connecting means, means responsive to' connectionwith an operated indicating means for generating a pulse of tone, means responsive tothe, release of. said .control circuit for rendering said registering means responsive to other digits, and means responsive to the reselection ofsaid, control circuit and the registration of oneof. said'other digits to disable said connecting means a'ssociated'with 11. In a telephone system, subscribers lines divided into groups, switching equipment, connecting means responsive to the initiation of a call on any one of said lines for connecting said lines with said switching equipment, said connecting means also divided into groups, indicating means operated when each one of said groups of connecting means becomes busy, means for determining which of said groups of connectin means are busy comprising a control circuit, means for selecting said control circuit, registering means in said control circuit, means for repeatedly positioning said registering means in response to the same predetermined digit, means responsive to a predetermined number of reoperations of said registering means for successively connecting with the indicating means of each of said groups of connecting means, means responsive to connection with an operated indicating means for generating a pulse of tone,

means responsive to the release of said control circuit for starting a timing operation, and means responsive to the reselection of said control circuit prior to the termination of said timing operation and the repeated registration of another digit to disable said connecting means associated with one of said group of lines.

12. In a telephone system, subscribers" lines divided into groups, switching equipment, connecting means responsive to the initiation of a call on any one of said lines for connecting said lines with said switchng equipment, saidconnecting means also divided into groups, indicating means operated when each one of said groups of connecting means becomes busy, means for determining which of said groups of connecting means are busy comprising a control circuit, means for selecting said control circuit, registering means in said control circuit, means for repeatedly positioning said registering means in response to the same predetermined digit, means responsive to a predetermined number of reoperations of said registering means for successively connecting with the indicating means of each of said groups of connecting means, means responsive to connection with an operated indicating means for generating a pulse of tone, means responsive to the release of said control circuit for starting a timing operation, and means effective if said control circuit is reselected prior to the termination of said timing operation to selectively disable the connecting means associated with a particular group of lines or to reenable said connectingmeans in accordance with the digit registered.

JOHN BAUMFALK.

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