US1732184A - Telephone system - Google Patents

Description

Oct. 15, 1929. J. l. BELLAMY ET AL TELEPHONE SYSTEM Original Filed Oct; 11, 1926 5 Sheets-Sheet 1 ANA MA In'fa'u'TFs Jul-m IBalIamy and Rndnay E. Richardson Oct. 15, 1929. J. 1. BELLAMY ET AL 1,732,184

TELEPHONE SYSTEM Original Filed Oct. 11. 1926 5 Sheets-Sheet 2 Juhn [Bellamy and Rodney E Richardson Oct. 15, 1929. J. l. BELLAMY ET AL 1,732,134

r TELEPHONE SYSTEM Original Filed Oct. 11, 1926 5 Sheets-Sheet 3 John IBaZlamy anufiudney EEichardsLm Oct. 15, 1929. J. I; BELLAMY ET AL 1,732,184

TELEPHONE SYSTEM I Original Filed 001:. 11, 1926' 5 Sheets-Sheet 4 L Q g g W gm. ,|-H. gm ,|-H-

' Inuenlur's Oct. I5, 1929. J. I. BELLAMY ET AL TELEPHONE SYSTEM 5 sheets-sheet s Patented Oct. 15 1929 UNITE. STATES PATENT orrics JOHN I. BELLAMY, F BROOKFIELID, AND RCDNEY G. RICHARDSON, OF CHICAGO, ILLI- NOIS, ASSIGNOBS T0 AUTOMATIC ELECTRIC INC, OF CHICAGO, ILLINOIS, A CO3- IOBATION or DELAWARE Application filed October 11, 1926, Serial The present invention relates to telephone systems, and the object is the production of a new and improved call director system.

Call directors are employed in multiofilce telephone systems primarily for the purpose of routing calls from the calling ofiice to the terminating ofiice through intervening oifices by way of the most economical path. In order for the trunking operations to be properly controlled, it is necessary that a diiierent registration be made for each ofiice in the system. When a system contains a relatively small number of separate ofiices, two digits sufi'ice to identity the called ofiice, and these two digits are registered on two-motion hundredpoint switch. In the case of a larger telephone system, three digits are used to designate each office, and a plurality of two-motion switches may be used in each director. The first ofiice digit in this case is registered on a single-motion switch which selects the appropriate two-motion switch to register the second and third oflice digits. An arrangement of the foregoing character is disclosed in the copending application of Richardson et al., Serial No. 538,551, filed Feb. 23, 1922. A director so constructed, however, is expensive. on account of the number of two-motion switches required.

an arrangement for simplifying the individual directors by providing a director selector to respond to the first oi'lice digit and select a director-containing a single oifice register capable of registering the second and third digits in the number. In other words, the directors are split into groups and each group corresponds to a different first otfice digit. In this way, the cost of the individual directors is greatly reduced, but the advantage is offset to a certain extent because the etliciency of the directors as a-whole is lowered on account of the fact that they are sub-divided into relatively small and inefiicient groups.

T he general object of the present invention ma now be stated to be the oroduction of a new and improved grouping arrangement TELEPHONE SYSTEM No. 140,720. Renewed January 31, 1929.

ofiice digit is dialed and it automatically rotates to find an idle oilice register in the selected group. In this way, although the registers that record the second and third digits are split into a number of groups as before, the directors themselves are all in one group.

Although the foregoing sets "forth the general arrangement of the grouping, the grouping arrangement is suiiiciently flexible to permit a certain number of single-digit ol'lice designations if such are desired and to permit a certain number of two-digit ofilce designations to be used.

In certain respects, this invention may be considered an improvement on the copending Bellamy application Serial No.

753,796, filed Dec. 4, 1924, and on our 00-- pending application, Serial No. 51,938, filed Aug. 2st, 1925. In their Patent No. 1,702,392, granted Feb. 19, 1929, Richardson et al. disclosed There are other objects and features of the invention which can be understood best from a further perusal of the specification. Referring now to the drawings comprising Figs. 14, there is shown 1n Figs. 16 a sutiicient amount of equipment in an automatic telephone system employing the features of the invention to enable the invention to be understood, and Fig. 7 is a layout showing how the sheets of drawings should be assembled in order for the invention to be understood best.

Fig. 1 shows a line which may be eX- tended, when calling, by the lineswitch LS to the selector S by way of the trunk circuit TC. The director selector DS is provided to connect an idle director to the trunk line through the trunk circuit TC when the trunk line is seized.

Figs. 2, 3, and 1, show one of the directors accessible to the director selector DS, Fig. 1. The portion of the director shown in Fig. 2 includes the input control switch ICS which distributes the series 01"- incoming impulses, and the output control switch OCS which places the sending switch SS, Fig. 3, under the control. of the registers in the proper order. Fig. 2 shows also the register selector which operates upon the seizure of the director to extend connection to an idle A-di git register.

The portion of the director shown in Fig. 3 includes the sending switch SS and the associated control relays. g The portion of the director shown in Fi '4 includes the class register CR, the thousanc s register TH, the hundreds register H, the tens register and the units register U.

5, shows the register switch A which re sponds to the first ofiice digit and selects a-n idleregister in the group corresponding to the first digit. This drawing shows also the register B accessible to register A through the sixth level of the latter. Register B is a single motion switch, and is taken into use to register the second digit in certain designations that contain only two o-flice digits. The register BC is accessible to register A through the fourth level of the latter, and it registers the second and third otlice digits when it is used. The register BC is accessible to the register A through the second level of the latter and it registers thesecond and third. igits in the office designations starting with the. di it 2 in case the called office has a three a the entire exchange battery oi twenty-tour digit designation. If the called ofiice has a two digit designation, the registration is completed by the register B which is individual to and operates in synchronism with the primary magnet of register BC. The register BC isa two-motion switch identical with the register BC, and the register B is a single "motion switch identical with the register B.

The wipers of the registers BC and B it will befn'dted are connected in multiple, and the bank contacts of both registers are wired up to the left-hand side of the intermediate distributing frame I. D. F. In case a certain office designation beginning with the digit 2 hasonly two digits, the corresponding bank contacts of the register B are connected up at the I. D. F. and the corresponding level of I baiik contacts of the register B are left dead corresponding to the live levels of the register The'zero operators trunk circuit containing relay531 is accessible to the A register through the tenth level.

Provisions are ordinarily made for routing calls to an operator responsive to the simple act of dialing the letter 0,

dialed connections are made directly to the I. D. F. independent of any further registers.

The intermediate distributing frame I. D.

registers.

Fig. 6 shows the battery B with taps taken oli c'om'niencing at the grounded terminal of the said battery and being spaced two cells apart, there being twelve taps in all. This battery, it will be understood may be the reg ular exchange battery, which is usually of the 48-volt type comprising twenty-four or more cells. It will be noted that the battery taps are shown extended'to circles numbered to The circles at the left of the bat- 'tery represent terminals that are to be connected to corresponding terminals on the lefthand side of the intermediate distributing frame I. D. F, and the circles at the right of the battery represent terminals that are to be connected to corresponding terminals in Figs. 3 and 4. It is to be understood that the remaining battery symbols shown throughout the drz twings 'all indicate the same battery, and that, although only two cells are shown,

or more cells is meant in each case.

Gall to the zero opera-tor It will now be assumed that a subscriber desiring to get into communication with the zero operator removes his receiver and dials the digit 0. It is assumed that the director translates the digit 0 into the code 920. Assuming that the calling line is the one shown in Fig. 1, the lineswitch LS operates in the usual manner to extend the connection to an idle selector, such as the selector S. When the trunk line extending through the trunk circuit TC to the selector S is seized, line relay 104 energizes over conductors 101 and 103 and at armature 110 closes a circuit for relay 105. Relay 105 at armature 112 places ground on release trunk conductor 102 so as to maintain the lineswitch LS operated. At armatures 113 and 114, relay 105 closes the switching relay and test circuits, respectively, of the director selector DS. The director selector DS now operates in the usual manner to select an idle director, the stepping magnet 141 operating through its self-interrupting contacts, armatures 114 and 118, armature 149, normal, and test wiper 145. Switching relay 142 is short circuited as long at the hunting operation continues, but the short circuit is removed when an idle director is encountered, whereupon relay 1 12 energizes through armatures 117 and 113, and the stepping magnet 1 11. Upon energizing, relay 142 at armature 149 disconnects test wiper 145 from the test circuit and connects it to ground, thereby making the seized director busy; at armature 150 it connects up the impulse conductor to wiper 1 16; and at armatures 1 17 and 14.8 it extends conductors 107 and 109 to wipers let?) and 1&4. Assuming that the director seized is one shown in Figs. 2%, the line relay (not shown) of the selector S energizes over conductors 151 and 152 and prepares the selector for operation.

In the seized director, relay 302 energizes over release trunk conductor 153 responsive to the grounding of the said conductor by the director selector DS, and at armatures 310- S12 opens the various release circuits of the director, at the same time preparing at armature 312 a circuit through the le'ithand wiper of the class register GR, Fig. 4:. A circuit is closed through armature 31 1, normal, for relay 806, which operates to prevent premature operation of the sending switch SS.

As a further result of the grounding of the release trunk conductor 153 of the director, a circuit is closed through armature 224:, normal, Fig. 2, for relay are of the register selector RS. Relay 21% operates and closes the switching-relay circuit of the register selector at armature 223, and at armature 222 it closes the test circuit of the register selector. As a result, the register selector RS operates in the same manner as previously described in connection with the director selector DS and it seizes an idle register, which selector it will be assumed is the register shown in Fig. 5. When the switching relay 213 operates it connects up the conductors 217221 at its lower armatures, and at armature 216 it opens the test circuit and grounds the test wiper, whereupon a circuit is closed through the upper winding of the two-step switching relay 501 of register A. The upper winding of this relay is a high resistance winding of a relatively small number of turns, and the relay operates through its first step only. At armature 505, relay 501 opens a point in the circuit 01 release magnet 513.

The calling subscriber may now dial the digit 0, whereupon line relay 10 1 of the trunk circuit TC, Fig. 1, falls back ten times. Each time it falls back it closes at armature 11 a circuit through armature 150, operated, wiper 146, conductor 15st, series relay 201, armature 228, wiper 206, an armature of relay 213, conductor 219, a wiper of the register selector RS, armature 508, normal, series relay 503, and vertical magnet 510 to battery.

By the operation of vertical magnet 510, the wipers of the A register are raised step by step and they come to rest opposite the tenth level otbank contacts. Relay 503 is energized in series with vertical magnet 510 and it maintains armature 516 attracted throughout the vertical movement. Upon the operation of armature 516, a circuit is closed from the grounded release trunk conductor of the A register for stepping relay 502. Relay 502 energizes and prepares at armature 15 a circuit for rotary magnet 512, and at armature 5141 it prepares a locking circuit for itself which is closed through oft-normal contacts 511 and the rotary magnet interrupter contacts upon the first vertical step of the switch shaft.

In the director, series relay 201 operates in response to the first impulse of current and it remains operated throughout the series of impulses. At its upper armature, relay 201 closes a circuit for relay 202, and. relay 202 prepares a circuit for stepping magnet a of the input control switch ICS, which circuit is momentarily closed at the end of the series of impulses, when relay 201 falls back, and pending the falling back of the slow acting relay 202. Accordingly, the wipers 205 of the switch 10S are advanced one step at the end of the digit 0. WViper 206 transfore the impulse conductor from the concuctor to which it is normally connected and connects it to the one next in order.

In the A register, Big. 5, when series relay 503 falls back at the end of the vertical move ment it completes the circuit or rotary magnet 512. Rotary magnet 512 operates and advances the wipers of the register into ongagement with the list set of bank contacts in. the 0 level. Near the end of its stroke, magnet 512 opens the circuit of stepping re-- lay 502, whereupon relay 502 falls back and opens the rotary magnet circuit. The rotary magnet falls back again, and closes its interrupter contacts. From this point, the operation depends upon whether the first set of bank contacts is busy or idle. If this set of contacts is idle, the lower winding of switching relay 501 energizes, operating the relay to seize the contact set. It the set of contacts is busy, the lower winding of switching relay 501 is short circuited by the ground potential encountered on the busy test contact by the test wiper (the upper wip er of the register) and does not operate. In thiscase stepping relay 502 is operated again and the wipers are advanced another step.

This alternate operation of stepping relay 502 and magnet 5112 continues until an idle contact set is reached, which contact set will be assumed is the one shown in the d rawings l Vhen this idle contact set is reached, switching relay 501, being no longer short circuited, energizes in a circuit including the grounded release trunk conductor of the switch, off-normal contacts 511, interrupter contacts of the rotary magnet, and stepping relay 502. The relatively low wound step ping relay 502 does not operate in series with relay 501. The energization of the lower *inding of relay 501 brings about the operation of the relay through its second step, and its armatures 50d and 506--510 are operated. Armature 50 1 opens the test circuit and con nects the test wiper to the grounded incoming reloasetrunk conductor, and the lower armatures connect up the remaining wipers oi the register. The grounding of the test wiper of the A register results in the closure of a circuit through the test contact of the seized set for both. windings of relay 531 in series. Relay 531 does not energize over this circuit at this time however owing to the fact that a circuit is closed for the lower winding directly as will now be pointed out. This circuit includes armature 229, normal, of relay 203, Fig. 2, an armature of relay 213, conductor 216, the associated wiper and bank contact, armature 507, the associated wiper and the bank contact on which it is standing, and the inner armature, normal, of relay 531. The upper winding of relay 531 is accordingly short circuited because ground potential is applied to both its terminals, and the relay not operated ow g to the fact that the lower winding is a relatively ineiiicient winding.

The second wiper from the top of the A reg ister is the wiper over which the class selection is controlled. It will be noted that the contact engaged by this wiper is connected directly with the I. D. F. and does not pass through contacts on relay 531. As a result, a circuit now closed from battery through the litth battery tap, the said second wiper from the top of the register A, armature 506, corresoonding wiper of the register selector RS, conductor 217, an armature of relay 21?), lower armature of relay 201, and the lower armature of relay 203 for the lower winding of the said relay. Since the other terminal of the lower winding of relay 203 is connected to the full voltage terminal of the exchange buttery, relay 203 energizes and at armature 226 closes a locking circuit including its upper winding and the grounded release trunk conductor At armature 227, relay 203 opens the circuit through its lower winding; it disconnects wiper 206 at armature 228; at armature 229 it removes ground from conductor216 and connects ground to interrupter 332, Fig. 8; and. at armature 225 it places ground on the second and third contacts in the bank 01" the input control switch 165, closing a circuit through wiper 205 and the self interrupting contacts tor magnet 204:. l'fdagnet 20st operates and advances the wipers 205207 through their second and third positions.

As a result of the removal of the ground potential from conductor 218 at armature 229, the short circuit is removed from around the upper winding of relay 531, Fig. 5, and relay 5 31 now energizes through the upper-wiper of the register A and the bank contact on which it is standing. The upper winding of relay 531 is a relatively efiicient winding, and the relay operates therefore, when both winding are energized in series. Upon operating, relay 531 connects the lower four associated bani; contacts to the corresponding contacts on the l. D. F, at the same time disconnecting the upper of the four contacts mentioned from the junction of its own windings.

it may be pointed out at this time that wiper 206, Fig. 2, is disconnected at armature 228, upon the operation of relay 203, so as to prevent any connection between the incoming impulse conductor and the I. D. F. which would occur otherwise during the advance of the input control switch through its second and third positions. Except for the necessity of an arrangement of this kind, a single wiper would replace the two wipers 206-207 of the input control switch. Also, relay 531, Fig. 5, coe ld be dispensed with entirely and the corponding conductors could be connected straight through except for the fact that it necessary to prevent connection between ooming impulse conductor and :the D. F. i is necess ry to prevent such connection 0wto the act that the incoming impulse conducto 1 is used also as an outgoing switching uctor, in a manner to be subsequently ded, to operate switching relay 106, Fig. 1. It a separate switching conductor were used it would. be no longer necessary to prevent the connection above mentioned.

Responsive to the grounding of the start conductor extending from the make contact of ari'nature 229, Fig. 2, to the upper terminal of the interrupter 332, Fig. 3, the setting of the class register CR, Fig. 4, is effected. he circuit oi? the operating magnet (the upper magnet) of the class register OR includes the interrupter 832, which is now grounded at its upper terminal, and armature 317, normal. Upon the first step ofthe wipers oi the class register GR, the righthand wiper of the register encounters a bank contact connected with the second battery tap. A circuit is now complete between the fifth battery tap and the second battery tap including ajumper and the upper I. D. F. terminal, Fig. 5, the next to the top bank contact of the set shown in the 0 level of the register A, corresponding wiper of the register A, armature 506, a wiper of the register selector, conductor 217, an armature of relay 213, a conductor extending horizontally across F igL2, polarized test relay 303, Fig. 3, armature 31-6, and the righthand wiper of the class register CR. Since the battery taps 2 and 5 are of dii'lere'nt potentials, there is current now flowing'through the test relay 803. However, test relay 303 is polarized so that the lower terminal must be nega tive with respect to the upper terminal in order for the relay to operate. Such is not the case at this time on account of the fact hat tap is negative with respect to the tap No. 2, and the tap which is positive with respect to battery tap 2 is battery tap N0. 1, which is the tap used for the class connection on the D. F. only when the call being handled belongs to class No. 1. Accordingly, the advance of the class register CR continues uni the control of the interrupter and by the operation of the operating magnet of the class register until live steps have been taken by the wipers of the class register. At this time, the righthand wiper oi' the register engages the sixth battery tap, which is negative in potential with respect battery tap No. 5 to which the other end oi the test circuit is now connected through the upper right-hand terminal of the I. D. F., Fig. 5. Test relay 303 now operates therefore, and at armature 313 closes a circuit for relay 304 including the grounded release trunk conductor 153. Relay 304 energizes and closes a locking circuit for itself at armature 315; opens the circuit through test relay 303 at armature 316; extends ground at armature 318 from armature 312, operated, to the left-hand wiper of the class register OR; at armature 334 connects up test relay 301; and at armature 31% opens the w initial circuit of stop relay 306 and closes a self locking circuit for the said relay through contacts 309 and armature 333. The right-hand terminal of test relay 301 is now connected through the operated armatures 3- 33st and 325 to wiper 210 of the output control switch OCS, Fig. 2. The conductor connected to the bank contact on which wiper 210 is now standing (in its normal position) is connected through a wiper of the register selector RS, and a wiper of the register A to the second (counting from the top) righthand I. D. F. contact, Fig. 5. This contact is cross connected on the I. D. F. to the ninth battery tap, as the first code digit to be transmitted in the present call is the digit 9. Any one of the first ten battery taps is positive with respect to the eleventh battery tap to which the left hand terminal of the test relay 301 is connected. As a result, relay 301 operates in such a manner as to separate the contacts 309 so as to permit stop relay 306 to deenergize to start the sending operation, the arrangement being such that this relay is peritted to deenergize to start the sending operation only when the connections are such that the sending operation will stop at a predetermined point. For example, it may be mentioned that, in making certain calls it is sometimes desirable that the digits registered on the registering apparatus shown in Fig. 5 be wiped out, and the outgoing control switch OCS, Fig. 2, is advanced through its first four positions to ell'ect the wiping out operation, in a manner which will be explained later. It is obvious that no sending operation is desired while the skipping oper ation is in progress and for that reason no sending can commence if the right-hand terin' al ot the polarized relay 301 is connected twelfth battery tap, as this tap is negawith respect to the left-hand terminal Or the relay and the relay operates the contacts to bring about the skipping operation. Continuing with the description, relay 306 cenergizes when its circuit is opened at conict 309 of relay 301 as above pointed out. at armature 333 relay 306 opens a further point in its locking circuit; at armature 325 it disconnects the test conductor fromtest relay 301 and connects it instead to test relay 305; and at armature 324 it extends a connection from the interrupter 332 to the stepping magnet 327 of the sending switch SS, this connection including armature 317,

operated. Magnet 327 now energizes and deenergizes under the control of interrupter 332, advancing the wipers 330 one step on eacii deenergization. Sending contacts 338 are opened on each energization of mag net 327, but the first opening is inettective on account of the fact that pick-up relay'305 (not yet operated) maintains-contacts 328 shunted at armature 319. On the first step of the wipers, wiper 330 closes a circuit for pick-up relay 305 from its grounded bank and relay 305 operates. At armature 319, it removes the shunt from around the sending contacts 328, and at armature 331 it closes a circuit through armature 323, normal, for stepping magnet 208 of the output control switch 063, Fig. 2. Magnet 208 energizes preparatory to advancing the wipers 209 211. On each operation of magnet 327 following the operation of pick-up relay 305, the outgoing control circuit, including conductors 151 and 152, is opened at contacts 323, and on each deenergization of magnet 327 the wipers 330 and 331 are advanced one step. fit the end of the first interruption, wiper 331 engages the second battery tap so as to energize the polarized test relay 307 in case the digit to be transmitted is the digit 1. In the present case, the digit to be transmitted is the digit 9 and the second contact from the top oi the right-hand side of the I. D. F, Fig. 5, is cross connected to the ninth battery tap as above pointed out, and, although current now flows through the polarized relay 307 the relay remains normal owing to the fact that it is operated only when the right-hand terminal is negative with respect to the left-hand terminal.

The sending operation continues until nine interruptions have been produced in the outgoing control circuit, and the wiper 331 engages a contact connected with the tenth battery tap at the end 01": the ninth interruption. Relay 307 is now operated owing to the fact that the tenth battery tap is negative with At armature 3263, relay 307 closes a circuit for stop relay 306. Stop relay 306 operates and shunts the sending contacts 328 at armature 322; opens at armature 323 the circuit ofmagnet 208, Fig. 2, and closes a locking circuit for itself; again completes its previously-closed locking circuit at armature 333; at armature 325 switches the test conductor back into connection with test relay 301; and at armature 324 disconnects stepping magnet 327. from the interrupter 332 and connects it instead in a local circuit including the selfinterrupting contacts 329 and the restoring wiper 330. As a result, magnet 327 operates rapidly in a buzzer-like manner and spins wipers 330- and 331 around. to their normal position, whereupon the operation of magnet 327 ceases and the circuit of pick-up relay 305 is opened.

As a result of the rleenergization of magnet 208, Fig. 2, the wipers 209211 of switch OCS advances one step, and wiper 210 connects the test conductor to the second code digit wiper of the register A through an obvious path. The second wiper of the register A is connected to the corresponding ILDFL contact and thence by way of a jumper to the second battery tap, as the second code digit to be transmitted is the digit 2. As the test conductor has been switched into connection with test relay 301, Fig. 3, this relay, having previously energized again through the first contact in the bank a wiper 210, Fig. 2, remains energized in such a direction as. to maintain the auxiliary locking circuit of relay 306 open at contacts 309'. As a result, the deenergization of pick-up relay 305, which shortly follows the restoration to normal of the sending-switch wipers, is followed shortly thereafter by the deenergization of stop relay 306, whereupon the next sending operation ensues. Relays 305 and 306 are slow acting relays, and the time required for them to fall back one after the other is providedto space the digit apart suificiently to secure the proper operation. of the switches.

Upon the deenergization of relay 306, the interrupter 332 is. again connected to stepping magnet. 327 of the sending switch SS and the second code digit is transmitted. As the left-hand terminal of the test relay 307 is now connected, as above described, to the second battery tap, the sensing operation is stopped when wiper 331 engages the third battery tap at the end of the second interruption in the outgoing control circuits.

The out-put control switch OCS, Fig. 2, is now advanced another step in the above described. manner and the third code-digitcontrol conductor extending to the righthand side of the I. D. F. is connected up. This conductor is connected on the I. D. F. to the fifth battery tap, and the third code digit transmitted is the digit 5. This digit is terminated in a manner similar to the first two, and the out-going control switch is advanced another step.

It will be noted that the fourth and last code-digit-control conductor in the set in use at present is cross connected on the I. D. F. to the skip conductor, corresponding to the twelfth batterytap. Accordingly, the test relay 301 is now energized in the reverse direction; contacts 309 remains closed and contacts 308 are closed. Upon the closure of contacts 308, a self-interrupting circuit is closed for magnet 208 of the switch OCS through the fourth bank contact and wiper 209 and the self interrupting contacts of the magnet. Accordingly, magnet 208 operates and restores, advancing the wipers from their fourth position to their fifth position.

Since the calling subscriber has dialed only the digit 0 the thousands register is in its normal position, and the fifth contact. in the bank of wiper 210 of the switch 0053 is dead- Accordingly, relay 301, Fig. 3, deenergizes and: remains in the position shown in the drawing, leaving the auxiliary locki'ng circuit of relay 306 closed until the director is released.

As the office registering apparatus is never needed inany case after the outgoing control switch OCS, Fig. 2, has advanced beyond its fourth position, a circuit is now closed for the upper winding of relay 215, 2 tlni'ough the fifth bank contact and. wiper 209, and magnet 208 of the switch OCS. Relay 2'15. energizes in this circuit, but mag net 208' does not operate on account of the relatively high resistance of the upper winding of relay 215.. At armature 224, relay 215 opens the circuit of relay 214 and closes a locking circuit for its lower winding. Accordingly, relay 21A restores and relay 215 remainsoperated until the director is re leased. lector RS at armatures 222 and 223, and relay 213 falls back and frees the register A by removing the ground potential from its upper wiper. Responsive to this removal of ground potential, relay 501 of the register A and relay 53'1 in the relay rack both fall back. At armature 505, relay 501 closes a circuit through the associated off-normal contacts for the release magnet 513, with the result that the register A is rest-cred to its normal position in the usual manner.

As the class register QR, has been pre viously set in its fifth position upon the receipt of five impulses by its operating magnet in the manner pointed out hereinbefore, a ground switching branch 154 of the combined switching and operating conductor 15A. The ground potential is applied through armatures 312. and 318, left-hand wiper and fifth ban-k Contact of the class register GR,

Relay 21 i releases the register sepotential is now applied to the ion a. law

and the fifth bank contact and wiper 211 of the switch 008. As a result of the placing of this ground potential on conductor a circuit is closed through wiper 146 of the director selector DS, Fig. 1, armature 150, armature 111, operated and switching relay 106 to battery. Relay 106 operates and closes a locking circuit for itself at armature 116; trees the director selector at armatures 117 and 118; and at armatures 115 and 112) disconnects conductors 101 and 108 :trom the windings of line relay 104iand connects them instead to conductors 107 and 109 extending to the selectorS. Relays 10 i and 105 new fall back. As a result of the release of the director selector at armatures 117 and 118, switching relay 142 falls back and trees the director, removing ground at armature 1&9 from release trunk conductor Release trunk conductor 153, however, remains grounded at armature 320 of pick-up relay 305 for an interval until pickup relay 805 has had time to fall back tollowing the restoration to normal of wipers 330 and 331 of the sending switch SS following the last digit. it will be remembered of course that the switching-through operation was set into motion upon the cnergization of stop relay 806. l his operation is completed, therefore, before the sending switch SS can restore to normal and permit the pick-up relay 305 to fall back. When pick-up relay 305 falls back, ground potential is removed at armature 320 from conductor 153, opening the auxiliary loch 1g circuit of relay 300 and opening also the circuit of release relay 302 and the locking circuits oit relays 203, 215, and 804-. When release relay 302 stalls back, it places ground at armatures 310 and 311 on all the center in the bank of wiper 209 of the switch UCS except the normal contact. This results in the buzzer-like operation of magnet 208 to advance the wipers the switch to their normal position. At armature 312, relay 302 closes circuit for the release magnets of the input control. switch ICS, Fig. 2, the class register CR, Fig. i, and the four digit registers shown in Fig. l. As a result, these switches are restored to their normal. pcsi tions in the usual manner. The director is now ready to handle another call.

Considering new the effect of the transmission ot the code digits 0, 2, and 0 by the director, the selector S, Fig. 1, responds to the first code digit 9 by raising its wipers opposite the ninth evel and selecting an idle trunk in that level; the selector to which this trunk extends responds to the second code digit 2 and extends the connection to further selector in its group; and the selector seized in accordance with the di i 1 in response to the tlrd and last code d to extend the connect on to the switchboard oi the zero operator. The zero operator responds and disposes of the call.

When the calling subscriber replaces his receiver, ground potential is removed from the release trunk conductor of the established connection at the relay equipment of the Zero operator or at an inter ening repeater. li hen this occurs, the line switch LS and the selector F release in the usual manner and relay 100 of the trunk circuit TC falls back. The connection is now released and the apparatus involved therein may be used in the establishment of subsequent connections.

Call 250 oyfiae 62, line It will now be assumed that the subscriber on the line shown in F ig. 1 desires to extend a connection to a line terminating in oliice 62. It is asumed that o'tlice No. 62 is a small otiice having, as yet, not more than 100 lines. Accordingly, the line designation consists of two digits. Assuming that the line desired is line L5, the complete number is 62a5.

It will be assumed that, when the subscriber removes his receiver, the lineswitch LS selects the trunk line extending to the selector S; that the director selector DS selects the director shown in Figs. Q- .l:; and that the register selector RS, Fig. 2, selects the register A, Fig. 5. Accordingly, when the calling subscriber dials the first otlice digit 6 the register A raises its wipers opposite the sixth level and selects an idle set of bank contacts in the hereinbefore described manner. Assuming that the selected contact set is the one extending to the register C, the two-step relay in the register C is energized through its first step only by means of the upper winding when the register is seized, the energizing circuit including the third wiper (counting from the top) of register A, which wiper is grounded through armature 220, normal, of relay 203, Fig. 2. The contact set is mar red engaged by the application of ground potential through the upper contact of the set by the register A through its test wiper, thereby closin a circuit through both windings of the relay A. The relatively efficient lower winding of the relay however short cir cuited for the time being owing to the fact that ground potential is applied to both of its terminals. Upon operating through its first step, the relay of the register C opens at its upper armature a point in the circuit ot the associated release magnet.

The wipers of the input control switch ICS, Fig. 2, are advanced one step in the herein before described manner by the joint scion of relays 201 and 202 at the end of the digit. Accordingly, the incoming impulse conductor is shifted by wiper 206 of the input control switch ICS from conductor 210 to conductor 220. Conductor 220 it will be observed is now connected to the fourth wiper o'l' register A, and the bank contact on which this wiper is standing is connected with the operating magnet of the register B through an armature of the associated relay. Accordingly, the magnet 530 responds to the second f 2 and brings the wipers of the register 13 engagement with the second set of associated bank contacts labeled (62). The upper banl: contact of this set (having to do with the operation of the class register) is connected up on the I. D. F. to the third battery tap so as to guide the class register Cl F. 4-, into its third position. The operation oi. class register is initiated in the hereinbefore described manner upon the falling back of the series relay 201, Fig. 2, and it results from the the sending switch SS by operating relay 30% at armature 313.

\Vhen the first line designating digit 4: is received by the director, the operating magnet of the thousands register DH, Fig. 4:, is operated four times through wiper 207, Fig. 2, in its fourth position. The wipers of the switch ICS being advanced at the end of the digit and the hundreds register H is operated through the fifth position contact of wiper 20? to record the second and last line designating digit 5.

Since the first code-digit contact in the set now in use by the register B is cross connected on the I. D. F. to the seventh battery tap; since the second code digit conductor is cross connected. to the fourth battery tap; since the third code digit conductor is cross connected to the third battery tap; and since the fourth code digit conductor is cross connected to the skip conductor (the twelfth battery tap) the sending switch SS, upon being started, transmits the code digits 7, 4, and 3 and the test relay 11 is operated in reverse direc tion in the fourth code-digit position of the switch OCS to cause this position to be shipped in the manner hereinbefore pointed out.

In the preceding call the switchingthrough operation took place responsive to the arrival of the wipers of the switch 003, Fig. 2, in through their fifth position. This does not take place at this time now owing to the fact that the class register GR is set in its third position instead of the fifth position.

The left-hand terminal of the polarized test relay 307 is new extended by wiper 210 of the switch OCS, Fig. 2, to the wiper of the viously been set in its fourth position to record the first line designating digit. Accordingly, polarized test relay 307 controls the sender so that it retransmits the registered digit 4. The advance of the switch 0C?) is automatically accomplished at the end of the transmission of the digit 4, and the test relay is connected up by the Wiper 210 to the wiper of the hundreds register H on which the second and last line-designating digit 5 is registered. As a result, the digit 5 is retransmitted in the usual manner.

V hen the wipers of the switch OCS advance again at the end of the retransmission of the second and last line-designating digit 5, wiper 211 closes the switch-through circuit upon coming into engagement with its seventh bank contact, the class register CR having been set previously in its third posi tion. is the same as previously placed and includes t 1e switch-through relay 106 of the trunk circuit TC. Responsive to the operation of relay 106 the director is released in the heroin before described manner and the two subscribers may converse with each other as soon as the called subscriber responds, the auto- .iatic switches having responded to the oper' ation of the sending switch SS to extend the connection to the desired line.

Assuming now that the director shown in the drawing is seized incidental to a call to office 112, line 128%, and that the register selector RS, Fig. 2, seizes the register A, Fig. 5, the register A as prepared for operation by the operation of the relay 504 through its first step.

When the first oflice digit 4 is dialed, the register A responds in the usual manner and: raises its wipers opposite the fourth level and selects an idle contact set. Assuming that the contact set selected is the one extending to the register BC, the two-step relay of the BC register operates through its first step Otherwise the switch-through circuitresponsive to the complete operation of relay 501 of register A.

hen the second ofiice digit is dialed, the register BC by means of its vertical magnet 529 raises its wipers opposite the first level, an d when the second office digit 2 is dialed the rotary magnet 524: of the register BC is operated through the lower wipers of the switches A. and BS and the third cont-act in the bank of wipers 206, Fig. 2.

When the series relay 201, Fig. 2, falls baclr at the end of the third oifice digit, a connection is established by the start relay 203 over the class conductor extending to the upper wiper of the register BC. It will be noted that the upper contact in the set M2 is connected on the I. D. F. with the first battery tap. That being the case, the class register CR, Fig. 4;, is stopped in its first position so as to allow the director to receive and retransmit four line-indicating digits before the switching-through operation takes place.

The thousands, hundreds, tens and units digits 1, 2, 3, and 4 are registered on the corresponding registers shown in Fig. 4.

By observing the connections made on the I. D. F. with the remaining contacts in the set 412, it will be noted that the code digits 8, 5, 2, and 6 are retransmitted. In this case the maximum number (4) of code digits are employed, and no special skipping operation involving the reverse action of relay 301, Fig. 3, is required, the switch OCS, Fig. 2, merely advancing one step at the end of each digit.

The operation of the sending switch and the step-by-step advance of the switch OCS continue until the registered line-designating digits have been retransmitted, and the wipers of the switch OCS arrive in their ninth position at the end of the retransmission of the last line-designating digit. As the wipers of the class register CR, Fig. 4, have been set previously in their first position, a circuit is now closed through the wiper 211 of the switch OCS,'in its ninth position, and the left-hand wiper of the class register CR, on its first bank contact, for operating the switching relay 106 of the trunk circuit TC with the hereinbeforedescribed results.

Call to ofit'ce 2192, line 1% Assuming that the director shown in the drawings and the register A are in use incidental to a call to oifice 212, line 123, andthat the register A has seized the joint registers B and BC upon responding to the first oflice digit 2, the second digit 1 received by the director is transmitted through the register A and is received by the operating magnet 521 of the single-digit register B. The digit is repeated by magnet 521 to the vertical magnet 523 of register BC. As a result, the wipers of the register B are placed on the first associated bank contact set (not shown), and the wipers of the register BC are raised opposite the first level of bank contacts. As explained hereinbefore, the first set of bank contacts of the register B are left dead on the I. D. F. on account of the fact that the first level in the bank of the register BC is a livelevel. For this reason, the setting of the register B is of no importance at this time.

When the third ofiice digit is dialed, the rotary magnet 522 of the register BC is operated through the lower wiper of the register A, and the wipers of the register are positioned on the second set of contacts in the first level, labeled (212).

It will be noted that the upper contact of this set is cross connected to the second bat tery tap with the result that the class re ister CR, Fig. 4, is set in its second position.

It will be noted that the cross connection is such that no code digits are transmitted in this case, the four code-digit positions being skipped.

Following the skipping operation, the three line designating digits are retransmitted. The wipers of the switch OCS arrive at this time in their eighth position. In this position of the wipers of the switch, the switch-through circuit is established through the eighth contact in the bank of wiper 211 and the second contact in the bank of the left-hand wiper of the class register CR, Fig. 4.

Call to 077506 22, line 1231;

It will now be assumed that the director shown in the drawings is taken into use incidental to a call to ofiice 22, line 1234; that the register selector BS seizes the register A, Fig. 5, and that the contact set extending to the registers B and BC is the one selected when the register A responds to the first ofiice digit 2. That being the case, both of the seized registers respond when the second office digit 2 is dialed, and the wipers of the register B come into engagement with the bank contact set labeled (2) in the drawing. The upper contact of this set is connected to the first battery tap so as to cause the class register CR, Fig. 4, to stop in position 1 in order to permit four line designating digits to be received and retransmitted before the switching-through operation takes place. The line designating digits 1234 are registered on the registers shown in Fig. 4 in the hereinbefore described manner.

It will be noted that the connections at the I. D. F. and involving the bank contact set (22) are such that the first code digit transmitted is the digit 2; the second code digit transmitted is the digit 5; and the third and fourth code digit positions are skipped.

As the class register CR, Fig. 4, has been set in its first position, a circuit is closed through the left hand wiper of the class register CR and wiper 211 of the switch OCS for bringing about the switch-through operation when the wipers of the switch OCS arrive in their ninth position following the retransmission of the units digit stored on the units register, Fig. 4.

The detailed description of the operation having been given, certain points of the arrangement will be discussed more fully in order that all parts of the invention may be made clear.

Considering particularly the class register CB, Fig. 4, and remembering that this class register is operated between the completion of the ofiice registration and the beginning of the transmission of the oflice code digits, it may be seen at once that it is desirable to complete the operation of the class register CE in theshortest possible time, so as to bring about wherein the greatest number of line-designating digits are used. In a telephone system most numbers contain four line-designating digits; considerably fewer numbers contains three line-designating digits; perhaps only one hundred numbers altogether may contain two line-designating digits; and only special calls such as those to the zero operator contain no line-designating digits. From this it will be seen that the positions assigned on the class register CR to the various classes of calls are in inverse order to the calculated relative numbers of the calls handled in a given time of the various possible classes.

Although only one function (the control of the switch-through operation) has been assigned to the class register OR in the present case, it is. evident that as the occasion may arise other functions may be assigned.

' Considering now particularly the arrangement employed. in connection with contacts 309 of relay 301, Fig. 3, to maintain relay 306 operatedin order to prevent prematurestarting of the sender, it has been mentioned hereinbefore how the stop relay 306 is maintained operated until a positive potential, with respect to the eleventh battery tap, is connected. to the right-hand terminal of relay 301 so as to hold up the starting of the sending switch SS until the skipping operation is completed in case it is desired to skip all code digit positions; It will be seen, however, that this arrangement comes into play on every skipping operation in order to prevent the starting of the sender until the skipping operation is completed. Furthermore, it may happenthat the output control switch arrives in fifth position in order to permit the first linedesignating digit to be retransmitted before the callingsubscriber has operated the thousands register shown in Fig. 4, to register the first line-designating digit. No special arrangements are necessary to handle this situation, as relay 301, Fig. 3, will not operate to open the contacts 309 to permit the sending operation to start, until the wiper of the thousands register has been moved onto its bank contact so as to provide current for operating relay 301. After relay 801 opens the circuit of relay 306 in such a case, the actual sending operation does not start until the slow acting stop relay 306 has fallen back. This permits the register to advance far enough before the starting of the sending operation to ensure that the register will not be overtakenby the sending switch in case along The connections between the digit is being, registered. and in case the dial at the calling substati'on'is running slow as, compared with the running speed of the sending switohSS.

Obviously, the sending operation is held up at any one of the line-designating sta es in case the corresponding register is non-oper ated when the output control switch 00S is advanced into a new position. Also, this arrangement prevents any possibility of a futile attempt of the sending switch SS to restart following the retransmission of the last digit in a number and pending the ultimatefre'cing of the director in response to the switclr ing-through operation.

What is claimedis:

1. In a multi-ofiice telephone system in. which telephone numbers arecomposed of ofice-designating digits and line-designating digits and in which desired connections are classedin accordance with their office designations, registering apparatus'for recording the respective ofiice designating digits, other registering apparatus for recording the line.

esignating digits, sending apparatus for retransmittingdigits inflaccorda'nce with the setting of the registering apparatus, aclass register individual to thesending apparatus, and meansfor operating said class register in accordance with the setting of the oflice. registering apparatus and under the direct control thereof until it is brought into the position corresponding to the class of the desired connection. ,4 V V p 2. In a telephone. system in which. telephone numbers are composed of oiiice-desig nating digits and line-designating digits and, in which thedesired connections areclassed in accordance'with the number of line-desig nating digits contained in called parties numbers, oiiice-registering apparatus, lineregistering apparatus, sending apparatus for retransmitting digits under the control of the oflice registering apparatus .and under control of the line registering apparatus, a class register having positions assigned co responding to the different classes of the desired connections, and meansfor operating said class register under the control of said office registering apparatus. I

3. Incombination, a sender, a plurality ofregisters for controlling said sender, said registers being common to said sender and a plurality of other similar senders, and a trunking switch operated in accordance with a digit in a telephone numberfor effecting a connection between an idle one of said registers and said sender. I 4. In a telephone system, a director includ ing a sender, registering devices divided into groups, means controlled in accordance with a digit in a telephone number for effecting a connection between. said director and an idle register in the group corresponding to such digit, means for operating the "selected I selected register.

5. In a telephone system in which numbers are divided into two portions, the first portion consisting of ofiice digits and the second portion consisting of line-designating digits,

i a director including a sending device and registering apparatus for registering the line-designating digits of called numbers, means for transmitting the digits of a telephone number to said director, oflice registering devices divided into groups, the devices in one group being arranged to respond to a different number of digits than the other devices, means responsive to the first digit received by the director for effecting a connection with an idle register in the group corresponding to such digit, means for transmitting the remaining portion of the otiice digits to the selected office register, and means automatically responsive to the completion of the operation of the selected oflice register for causing the remaining digits in the number to be transmitted to the line-designating digit registering apparatus.

6. In a trunking system for effecting con.- nections between a sending device and digit conductors for controlling the said device, a trunking switch having a directive movement to associate it with its different groups of contact sets and having a free hunting movement over the contact sets, single-digit registers connected between one group of contact sets and the digit conductors, twodigit registers connected between another group of said contact sets and said digit conductors, and connections between said digit conductors and another of said groups of contact sets independent of any digitregistering apparatus.

7. In a digit-register system, a single digit register, atwo-digit register having primary and secondary movements to register two digits, means for operating said registers simultaneously to register a single-digit designation, and for operating the two-digit regis' ter in its secondary movement to register the second digit of the designationin case a twodigit designation is being registered.

8. In a telephone system, two registers arranged to be set in accordance with digits of telephone numbers, and means effective in one call for operating the first register to recorda certain portion of the digits of the called number and for operating the second register to record a further portion of such digits, said means being effective in another call for operating the first register to record a larger portion of the digitsof the second called number.

9. In a register sender, means for operating the registering portion of the register sender to register a portion of a desired number and for preparing a circuit for controlling the number of impulses to be transmitted by said sender in accordance with the setting of such registering portion, means for starting the operation of the sender, and means for pre venting the starting of the operation of the sender in case the circuit for controlling the number of impulses to be transmitted by the sender is open.

10. In a register sender, means for operat ing the registering portion of the register sender to register a portion of a desired number and for preparing a circuit for controlling the number of impulses to be transmitted by said sender in accordance with the setting of such registering portion, means responsive to such registration for starting the operation of the sender, and means for preventing the starting of the operation of the sender in case the circuit for controlling the number of impulses to be transmitted by the sender is open.

11. In combination,an impulse sender for transmitting a series of impulses, digit control conductors. each corresponding to a different digit, a sender-control conductor, a registering device for connecting the sender control conductor with any one of the digit conductors, and means responsive to current flow over said sender control conductor for starting the operation of the sender and responsive to further current flow over said conductors for controlling the value of the transmitted digit; I

12. In combination, an impulse sender for transmitting a series of impulses, digit-control conductors each corresponding to a different digit, a sender-control conductor, a registering device for connecting the sendercontrol conductor with any one of the digit conductors, and means responsive to current flow over said sender-control conductor for starting the operation of the sender and for again stopping the operation of the sender in a position corresponding to the digit conductor with which the control conductor is con-' nected.

13. In a register sender system for use in a telephone system, a class register associated with a sender, a conductor arranged'to be extended by the registering apparatus, and means controlled over said conductor for starting the operation of said class register responsive to the complete extension of said conductor and for positioning said class register in accordance with the setting of the registering apparatus.

14:. In a register sender system for use in a telephone system, a class register associated with a sender, a' conductor arranged to'be extended by the registering apparatus, means controlled over said conductor for starting the operation of said class register responsive to the complete extension of said con ductor and for positioning said class register in accordance with'the set-ting of the registering apparatus, and means also controlled over said conductor for starting the associated sender to operating under the control of the registering apparatus.

15. In a register sender system for use in a telephone system, a class register associated with a sender, a conductor arranged to be extended by the registering apparatus, means controlled over said conductor for starting the operation of said class register responsive to the complete extension of said conductor and for positioning said class register in accordance with the setting of the registering apparatus, and means dependent upon the completion of the setting, of said class register for starting the associated sender to operating under the control of the registering apparatus.

16. In a register sender for use in setting up connections in telephone systems and containing a class registerarranged to be set in accordance with the class of a connection being handled as indicated by the setting of the registering apparatus, means responsive to the setting of the class register for start ing the sending apparatus to functioning under the control of the registering apparatus with the class of the connection as indicated by the set position of the registering apparatus, and means responsive to the arrival of the class register into the position corresponding to the class of the instant connection for transferring the impulse generating device'from association with the class register into association with the sending device.

18. In a register sender system for use in a multi-oflice telephone system, oiiice-registering apparatus responsive to the office-designatin'gdigits of called numbers, other registering apparatus responsive to the line-designating digits of called numbers, means for setting the registering apparatus in accordance with office designations containing vavious numbers of digits, and means automatically responsive to the registration of the lastoflice digit of a number for rendering the line-designatin registering apparatus responsivev to the next digit received.

19. In a director system, means for taking a director for use and for transmitting a telephone number thereto, registering apparatus for recording the number, sending apparatus operable in accordance with. the recorded number, a class register operable in accordcontrol of said apparatus, a secondary reg lster operated under the control of the same registering apparatus, and means for delaying the operation of the sender until the secondary register is operated.

21. In a director including a registering device responsive to a portion of a telephone number, means responsive to a setting of said device for transferring digits, a sender in said director responsive to, certain of said digits, and a class register responsive toanother of said digits,

22. In a register sender system, aprimary register, a. secondary register, and a sender, means tor operating said primary register directly in accordance with a portion of a, telephone number andmeans for operating,

said secondary register and said sender separately under the direct control of the primary register.

23. In a. register sender system, a register sender, a class register therein, local means for driving said class register, and means including a polarized test relay for stopping said register. v

24. In a director system, directors all in one group, registers divided into groups com mon to all said directors, means for taking a director for use and for transmitting aplurality of digits thereto, and means responsive to the first digit for selecting a group of registers.

25. In a director system, directors all in one group, registers divided into groups common to all said directors, means for taking a director for use and for transmitting a plurality of digits thereto, and means responsive to the first digit for selecting a group of registers and forautomaticallyselecting an idle register in the selected group.

26. In a director system, oflice registersidivided'into a plurality of groups, each group corresponding *to a different character in telephone designations and directors-all in one group and arranged to have common access to said registers. v p, 3:

27. In a telephone system employing a director system, means for taking a telephone line for use, and for associating a director therewith, oiiice registers divided into sep I therewith, oiiice registers divided into separately designated groups, and means responsive to the transmission of the designation of a group from said line to the associated director for associating an idle oflice register in the designated group with said director, the associated office register being operable from the said line to register a portion of a telephone number.

29. In a telephone system employing a director system, means for taking a telephone line for use and for associating a director therewith, ofiice registers divided into separately designated groups, and means responsive to the transmission of the designation of a group from said line to the associated director for associating an idle oflice register in the designated group with said director, the associated office register being operable from the said line to register a portion of a. telephone number, and automatic switching apparatus effective to extend the line in accordance with the setting of the operated register.

30. In a telephone system employing directors, means i'or taking a telephone line for use and for associating any one of a plurality of directors therewith, and office-registering apparatus including apparatus common to all said directors for registering three oflicedesignating characters sent to the director from the said line.

31. In a director system, a plurality of directors, a plurality of common office regis ters, a plurality of common oflice register selectors having access to said oflice registers, and switching mechanism responsive to the seizure of a director for connecting it to an idle office register selector.

32. In a registering device for use in a multi-ofiice telephone system, oflice-digit registering apparatus, line-digit registering apparatus, means for transmitting digits to said device, a distributor arranged to divert the oifice digits to the oilice registering apparatus and to distribute the remaining ones to the line registering apparatus, and means for causing said distributor to divert a less number of digits in some cases than others.

33. In a. director, an input-control switch arranged to advance a given distance in response to each digit received, and means for advancing said switch an additional amount between two digits.

In witness whereof, I hereunto subscribe my name this 8th day of October, A. D. 1926.

JOHN I. BELLAMY.

In witness whereof, I hereunto subscribe my name this 8th day of October, A. D. 1926.

RODNEY G. RICHARDSON.

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