US2089338A - Telephone system - Google Patents

Description

1937. w. w. CARPENTER ET AL 2,089,338

TELEPHONE SYSTEM Filed March 11, 1936 8 Sheets-Sheet l .W. w. CARPENTER Sf'A. E. HAGUE AT TOR/VEV Aug. 10, 1937. w. w. CARPENTER ET AL 2,089,338

TELEPHONE SYSTEM Filed March 11, 1956 8 Sheets-Sheet 2 /NVENTOR$,W l4. CARPENTER 'A.E. HAGUE 51/ ATTORNEY Aug. 10, 1937- w. w. CARPENTER ET AL 2,089,338

TELEPHONE SYSTEM Filed March 11, 1956 8 Sheets-Sheet 5 INVENTORSZW. W. CARPENTER By AE. HAGUE AT TORNEV 1937- w. w. CARPENTER El AL 2,089,338-

TELEPHONE SYSTEM Filed March 11, 1936 8 Sheets-Sheet 4 EADER FULL 4.90 F/G4 FULL MECH JUNCTOR "8"JUNC7'0R PM .w. m CARPENTER 351 ,5. HAGUE ATTORNEY Aug. 10, 1937.

w. w. CARPENTER El AL 2,089,338

TELEPHONE SYSTEM Filed March 11, 1936 8 Sheets-Sheet 5 U, y n I ATTORNEY Aug. 10, 1937.

w. w. CARPENTER ET AL 2,089,338

TELEPHONE SYSTEM Filed March 11, 1936 8 Sheets-Sheet 6 .W. W. CARPENTER gfnf. HAGUE ATTOPNEV Aug. 10, 1937. w. w. CARPENTER ET AL 2,089,338

' TELEPHONE SYSTEM Filed March 11, 1936 8 Sheets-Sheet 7 INVENTOAZ: 5 HAGUE ii o a. 20 unnecessary duplication of equipment.

Patented Aug. 10, 1937 UNITED STATES PATENT OFFICE TELEPHONE SYSTEM Application March 11, 1936, Serial No. 68,263

10 Claims.

oifice, registering devices are employed which are associated with the incoming trunk circuit. In the case of trunk circuits incoming from dial offices, the registering devices are positioned by means of revertive impulses under the control of the originating sender. In the case of trunk circuits incoming from manual ofiices, the registering device is also associated with an operators position and receives its setting under the control of the operator.

Heretofore, separate switching arrangements have been employed in connecting dial and manual trunk circuits with their respective registering devices. If either group of registering devices is small, this separation requires an In accordance with the present invention, a unitary switching device is provided for connecting the trunk circuits and registering devices together with means for permitting connections between corresponding equipment only.

.More specifically, the switching device comprises primary and secondary cross-bar switches with interconnecting links in which primary contacts and links are individual to the trunk types W and secondary contacts are individual to register types, the links having access to both register types. Means is provided to record the type of trunk seizing the switching device and responsive to this record, only the corresponding type of register may be tested and connected with.

The present disclosure forms a part of the complete system disclosed in the application of W. W. Carpenter, Serial No. 68,262, filed March 11, 1936.

The invention will be more clearly understood from a consideration of the following description in association with the drawings in which:

Fig. 1 shows the sender group testing and link lock-out relays;

Fig. 2 shows a number of control relays;

Figs. 3 and 6 show the multicontact connecting relays;

Fig. 4 shows a part of the sender link switches;

Fig. 5 shows the junctor group and selecting relays;

Fig. '7 shows the sender selecting relays;

Fig. 8 is a skeleton showing of the sender connector; and

Fig. 9 shows the manner in which Figs. 1 to 7 are to be arranged. 1 Referring first to Fig. 8, the sender connector consists of three primary cross-bar switches and three secondary cross-bar switches. The junctors are connected to contacts appearing in the horizontals of the primary switches; the senders are connected to the horizontals of the secondary switches; while the links connect verticals of the primary switches to verticals of the secondary switches. The primary switches are split vertically to divide the links into groups of three, and ten junctors are connected to the horizontals served by each group of three links, being multipled between switches where necessary. Therefore the primary switches provide thirty links for serving one hundred junctors. The three links of one group are connected one to each of the three secondary switches, thereby giving each incoming junctor access to all of the thirty senders. As will be pointed out in the description of the circuits, assuming that certain groups of junctors, for example groups 1 to H], are incoming from manual ofiices, they will be served only by the B senders. Such junctors are grouped by themselves and are therefore served by links individual to that purpose. However, the links have physical access to all senders sothat regrouping of the junctors may take place without rewiring the switches themselves. It is, of course, to be understood that the grouping shown is merely illustrative.

Detailed description This link control circuit, like the line group and control circuit described in the application of W. W. Carpenter, above-identified, is arranged to act as an emergency control circuit for an adjacent or mate frame. The dotted rectangle 350 of Fig. 3 has been used as a convenient means of indicating the relationship between the two control circuits and all conductors entering the rectangle are considered to emerge at the mate frame.

Test for presence of idle link and sender Turning now to Figs. 1 to '7, when a full mechanical junctor has been seized, it grounds conductor 42! completing a circuit over the inner back contact individual to that junctor on relay 62L back contact of primary hold magnet 425, conductor 426, outer back contact of relay 109, conductor I30, outer right back contact of relay 62L contact of jack 647 to the winding of group relay 622 and battery. The circuit of relay 622, which is individual to the group of ten junctors including the calling junctor, also extends in parallel over the back contacts of the hold magleft back contact of relay 228.

nets individual to the other two sender links which serve this group of junctors and over the back contacts of the corresponding sender group busy relays. Relay 52! is operated if the control circuit is busy, hold magnet 425 is operated if the corresponding sender link is in use with another junctor and relay l'99 is operated if all of the fullmechanical senders in the corresponding group are busy. Therefore, relay 622 can only operate if the control circuit is idle and an idle link to an idle sender is available.

Connecting junctor group to control circuit Assuming that relay 922 operates, at its inner right contact, it closes a holding ground for itself over the contacts of magnet 425, relay 199 and relay 62L It also connects ground over its outer right contact, conductor 64!, and the right back contact of relay 546 to the winding of relay 552 and battery, to start the control circuit functioning. With relay 552 operated, a circuit is closed from battery through the winding of relay542, through rectangle 959, over the right back contact of relay 559 or the inner right back contact of relay 543 of the mate control circuit, indicating that the mate control circuit is functioning, back through rectangle 359, inner left back contact of relay 559 and the outer left back contact of relay 543 of the home control circuit to ground at the left front contact of relay 552. Relay 542 in turn closes circuits from battery through the windings of relays 399 and 699, over its left contacts in parallel, over the left back contact of relay 545, conductor 554 to ground at the inner Relays 399 and 599 connect the junctor group circuits and the sender group circuits to the home control circuit. Relay 542 also opens the circuit of relay 545 to prevent interference from the mate frame until the control circuit has completed its function. It also connects ground over the outermost front contact of relay 599 to conductor 554 to hold relays 699 and 399 operated.

Choosing jnnctor group to be served With relay 699 operated, an indication of the group within which the calling junctor lies is given to the control circuit. Ground from the middle right contact of relay 622 extends over conductor 621, armature 692 of relay 599, conductor 693, outer back contact of relay 539 to the winding of relay 529 and over the normal contacts of the lower numbered group test relays to battery at the back contact of 'relay 529. Relay 529 closes a holding circuit to battery at its inner upper front contact. If junctors in other groups were calling, their relays might also operate, but preference is given to the highest numbered group by reason of the chain wiring of relays 529 to 529. Assuming relay 529 operates, it extends its operating ground over its lower front contact, over the upper back contact of relay 5H) to the winding of relay 54! and battery. Relay 529 also closes a circuit from ground over its outer upper front contact, armature 594 of relay 699, winding of relay 629 to battery. Relay 629 connects the individual group circuit serving the calling group of junctors to the control circuit.

Choosing y'unctor to be served Relay 529 in operating connects the ten start leads such as conductor 42L from the ten junctors of the group, through to the ten trunk test relays 599 to 599, conductor 42! extending over armature 528 of relay 629,.armature595 ofrelay 599, inner lower back contact of relay 519 to the winding of relay 599 and battery. It will be noted that the start conductors of the ten trunks of the group are connected together at the contacts of relay 625. Therefore the ground from conductor 42! also extends over other back contacts of relay 52! and front contacts of relays 629 and 999 to the windings of relay 599 and the rest of the trunk test relays. Each relay locks to its operating ground, independent of relay 5l9. With all of the relays 599 to 599 operated, a circuit is closed from battery through the winding of relay 52!, armature 629 of relay 529, armature 9960f relay 599, left back contact of relay 549,

inner upper front contacts of relays 599 to 599, inner left contact of relay 54! to ground at the middle lower front contacts of all of the relays 599 to 599. Relay 62d in operating looks over its right front contact, conductor 64f, armature 642 of relay 629, armature 69'! of relay 599 to ground. It also disconnects the multiple ground from the trunk relays and releases relay 622. Those relays, such as relay 599 which correspond to calling trunks remain locked, but the remaining relays release.

The release of relay 622 closes a circuit from battery through the winding of relay 549, armature 698 of relay 599, armature 63l of relay 629, back contact of relay 622, armature 632 of relay 629, armature 699 of relay 699, outer lower front contact of relay 599 to ground over the operating circuit of that relay. Relay 549 looks in a circuit from battery through its winding, armature 698 of relay 599, armature 63! of relay 629, back contact of relay 622, armature 632 of relay 929, armature 699 of relay 699, to ground at the fifth right contact of relay 549. With relay 549 operated, a circuit is closed at its fourth right contact for relay 539. Relay 539 opens the operating circuits of the group relays 529 to 529, leaving the highest numbered operated relay, in this case relay 529, looked over the inner front contacts of relay 529, outer left contact of relay 54! to ground at the middle lower contacts of the operated trunk test relays. When relay 549 operates, it closes a substitute holding circuit for relay 529 which may be traced from battery over the inner upper front contact, winding and lower front contact of relay 529, middle left front contact of relay 549, armature 6 ll of relay 699, arma-- ture 634 of relay 629, back contact of hold magnet 425, conductor 426, outer back contact of relay E99, conductor E39, armature 533 of relay 629, armature 5l2 of relay 669, to ground at the third right contact of relay 549. Parallel holding circuits extend over the other hold magnets and sender group relays serving the group. Therefore, if all links or all sender groups become busy, relay 529 releases, in turn releasing the group relay 529 to normal so that other calling junctors may be served.

Relay 549 also closes a locking circuit for the preferred trunk relay 599 which extends over the inner and outer lower front contacts of relay 599 to ground at the outer right front contact of relay 549. This locking circuit prefers the lowest numbered relay, the higher numbered relays locking only over the back contacts of the lower numbered relays. However, if higher numbered relays were operated at this time, they would remain locked to ground on the corresponding start lead.

Relay 599 also closes an obvious circuit for relay 5E9 which opens the operating circuits of the trunk .test relays. Relay 5E9 also opens the the primary sender selector.

' chain.

circuit of relay 54l which releases, but due to its slow-to-release characteristic, only after an interval. Relays 536 and 5I6 in operating prevent the operation of any further group and trunk relays should additional calls be received.

Operating select magnet of primary sender selector Relay 5! also closes a circuit for the select magnet corresponding to the preferred junctor in This circuit may be traced from ground at the outer left back contact of relay 228, conductor 236, upper front contact of relay 5I6, outer upper front contact of relay 566, armature 6) of relay 666, winding of primary select magnet All) to battery, and in parallel to the select magnets of correspondingly positioned junctors in the other primary switches.

Test for idle sender group and link In the meantime the control circuit has been testing for a sender group and sender. Since this is a full mechanical incoming junctor, group relay 626 connects ground over its armature 635 and armature 6I3 of relay 666 to conductor SM and the winding of relay I26, which is individual to this junctor type and connects the group test relays to the circuits controlled by full mechanical senders only.

Assuming an arrangement similar to that shown in'Fig. 8, each group of ten senders includes eight full mechanical senders grouped in the top horizontals of the switch and two B senders grouped in the bottom two contacts of the switch. Each group of senders has a circuit such as shown in Fig. 7, relays H6 to H9 being individual busy relays for the senders and relays I26 to I29 serving to test the condition set up on the sender busy relays H6 to H9. Relays I68, I65 and 166 serve the full mechanical senders, while relays I55, E58 and 'I3I serve the B senders. With relay I26 operated, the three sender groups are tested to determine whether the link serving the calling trunk group is idle and'whether there are two or more full mechanical senders idle in the group. One sender group test circuit may be traced from ground at the left back contact of the link hold magnet 425, armature 636 of relay 626, armature 6I5 of relay 660, conductor 6I6, outer right back contact of relay 22I right winding of relay I66, right back contact of relay I21, outer left front contact of relay I26, conductor I3I,'armature 3I6 of relay 366, left back contacts of relays I62 and I65, outer left back contact of relay H6 to battery over the left normal contact of the next lower unoperated relay in the chain. A similar circuit is closed over the outer back contact of each unoperated relay except relay II 1, which belongs to the last full mechanical sender of the group, to battery over the inner left contact of the next unoperated relay in the Where operated relays intervene, the chain is extended to the following relay. This relay arrangement is disclosed and claimed in the application of A. J. Busch, Serial No. 68,240, filed March 11, 1936.

Circuits similar to the one traced for relay I 66 are closed for relays I6! and I62 if the corresponding link and two full mechanical senders of the group are available. Assuming that relay I66 is operated, a circuit is closed from ground over the normal contacts of relays I63 and I64 through the winding of relay I65, armature SI?! of relay, 366, outer, right front contact of relay I66, right back contact of relay I62, left back contact of relay 2I8, conductor 232, inner left front contact of relay 546, conductor 555, right back contact of relay 228, resistance 229 to battery.

seizing sender group Relay I65 is individual to the group of senders represented by relay I66 in this link circuit. A similar relay (not shown) is provided for each of the other sender groups. Relays I63 and I64 belong to the same sender group as relay I65 but are a part of other link circuits. These relays are arranged in a lock-out chain in order to individualize the sender group to a particular link circuit and to prevent interference from other link circuits. In this case the link circuit shown has the last preference for the sender group shown and relay I65 can only operate if no other link control circuit is attempting to connect with this group of senders. Relay I65 when operated locks to ground at its own front contact and renders relays I63 and I64 ineffective by disconnecting ground from their left armatures. With relay I65 operated, a locking circuit is closed for relay I66 which may be traced from battery through the left winding and over the inner left front contact of relay I66, armature 3II of relay 366, outer left front contact of relay I65, to ground. This same ground is extended over the inner left front contact of relay I65, armature 3I3 of relay 366, to the winding of relay 22I and battery. A circuit is also closed from ground at the middle right contact of relay I65 to the winding of relay I62 and battery. Relay 22I opens the operating circuits of relays I66, MI and I62 causing relays ml and I62, for which no locking circuits have i been provided, to release.

Reserve sender group test When relay 54I closes its back contact, a circuit is closed from ground at the right back contact of relay 54 I, outer left front contact of relay 546, conductor 556, winding of relay I27 to battery. If none of the relays I66, IM or I62 has operated by this time, relay I 27 transfers their circuits from the regular test over back contacts of the sender relays 'II6 to II I, to the reserve test to battery over the back contacts of relays I62 and I65 and the similar relays of the other sender group circuits. Relay 165 is operated over the outer left front contacts of relays H6 to II! when all of the full mechanical senders of the group are busy, thereby opening the circuit of the corresponding sender group relay. Therefore for groups having a single idle sender, relay I65 will be unoperated and such a group may be selected. The operation of relay 162 from relay I65, when the regular test is satisfied, cancels this reserve test, although relay I2! is operated.

Selection of idle sender With relays I66 and I65 operated and locked, the control circuit is ready to select an idle sender in the selected group. A circuit is first closed from ground over the middle left contact of relay 22I, outer left front contact of relay I66, outer left back contacts of relays I 6| and I62, middle left front contact of relay I66, armature 3M of relay 366, outer right contact of relay I65, winding of relay I56 to battery. Relay V56 connects the circuits of the selected group of senders to the control circuit.

Relay I56 connects ground to conductors I8I,

182, E83 and 184. These conductors extend in multiple to the ten senders of the group but are ineffective until a sender has been seized. Conductor l8! controls a relay which reverses the direction of current flow over the contact of the stepping relay for calls received over part of the link circuits in order to save wear on the contact. Conductor F32 supplies holding ground to the sender until after the off-normal relay has operated. Conductors E83 and 584 carry the identity of the trunk group to the sender for transmission to the marker.

Operating select magnet of secondary sender selector Relay Hit also closes a circuit from battery through the winding of relay Hi8, armature of relay 'l-ili, conductor 53%, armature 330 of relay 3%, to ground at the outer right contact of relay i26. With relay lElB operated, the circuits for selecting a sender are closed. Each trunk normally prefers a different sender but in this case, with only eight senders available the preference of two pairs of trunks would be the same. Therefore relays 383 and W8 connect eight preference leads from the trunk relays 5st] to 599 through the windings of the eight sender selecting relays J25 to Hi over contacts of the sender busy relays lid to ill. Since trunk relay 50!] was operated, the circuit closed at this time extends from ground at the inner right front contact of relay 5%, middle upper front contact of relay 5%, conductor 55?, armature 3H3 of relay 3%, conductor 3H, armature it? of relay 7150, inner right contact of relay 768, right back contact of relay Hi1, assuming this sender to be idle, winding of relay was, left normal contacts of relays E21, 128, 129, etc., to battery. Relay 12o operates and locks to battery at its inner left contact and to ground over its inner right contact and armature 132 of relay 750. It connects ground over its outer right contact to the winding of relay N32 to hold that relay operated. At its outer left contact it closes a circuit from ground over armature 188 of relay i159, conductor 1189 to the winding of the secondary select magnet not individual to the selected sender. At the same contact it connects ground to conductor 5'92 to inform the sender that it has been selected. Relay 72% also connects ground over its middle right contact, armature E98 of relay E59, conductor lsl, armature EH8 of relay Salli, to the winding of relay 225 and battery.

When relay i552 operated, relay Ml was connected in parallel over the four left back contacts of relay M6, the four outermost armatures of relay 3%, armatures F93 to 96 of relay 550 to conductors is? to E99 and 75! leading in multiple to the group of senders to test them for the presence of false ground. If any one of these conductors is grounded falsely, relay ill operates, opening the circuit of relay H6 and blocking the progress of the call.

Operating linlc hold magnets If relay ill does not operate, the operation of relay 225 closes a circuit from ground at its inner right contact over the back contact of relay i ii for relay 9 i 6 which disconnects relay i ll from conductors E9? to E99 and l'5i. With relay H6 operated, a circuit is closed for hold magnets 424 and, 525, belonging to the link circuit connecting the calling trunk and selected sender, extending over the inner back contact ofrelay 523, armature $31! of relay 620, armature fill of relay Bill], conductor 6! 8, middleright front contact ofrelay I00, through the winding of relay ZIE shunted by the outer left back contact of relay 2%, inner right front contact of relay I It, to ground at the inner right back contact of relay 224. Magnets 324 and 425 operate, closing the cross-points prepared by select magnets 400 and tilt. When magnet 424 closes its cross-point, the operating ground for the magnets is extended over contact 445 of the secondary selector, conductor 4%, to the sender.

Test of sender holding circuit When relay Z20 connects ground to conductor 192, it causes the operation of a sender relay which connects conductor M6 to conductor 15i, armature 796 of relay l5fl, armature 3H5 of relay 300, inner left front contact of relay i is, winding of relay 220 and battery. Relay 22ft opens the shunt around the winding of relay 2E5 and relay 2E5 operates, provided there is no false ground on the sleeve conductor of the sender link. Such a ground, while holding the hold magnets and relay 225 would be in shunt of the winding of relay 2|5, preventing its operation and blocking the call.

Assuming relay 2H5 operated, it closes an obvious circuit for relay 214 which looks under the control of relay 22H. Relay 2 it connects ground over its middle left contact, outermost contact of relay 3Ull,'armature MS of relay l5), conductor EST, to the sender where it operates a relay which in turn connects ground to the winding of relay ill marking this sender busy to this and other link circuits.

Frame registration In the meantime, the incoming frame is identified to the sender by ground connected to conductors 183 and 784 as previously described. In response to the completion of the frame registration ground is closed over conductor W9, armature of relay 150, armature 326 of relay 3%, left back contact of relay 224, outer right contact of relay 2M, winding of release relay 228 and battery. This same ground is also extended to conductor 446 to hold the magnets 424 and 325 operated, independent of the control circuit.

Release of control circuit Release relay 228 locks under the control of relays 223, I21, 22!, H6, 540 and 5M if operated, to insure that it remain operated until the control circuit has restored to normal. It also connects ground over its left front contact, conductor 233, armature N9 of relay 6%, conductor 624, inner left back contact of relay 5&3, winding of relay 5% and battery. Relayt lt locks to ground at'the right front contact of relay 552, opens the circuit'of relay 552 and disconnects ground from conductor 558, thereby terminating the timing operation. Relay 552 releases relay 5 2 which in turn releases relays 6% and disconnecting the sender and group circuits from the control. circuit. The release of relay 6% in turn releases group relay 629, select magnet ilt, relay 5:30, the group test relay 529 and trunk test relay 566, as well as relays 5M and 533. 38s], in releasing, restores the link lock-out relay 555, sender group connect relay 15B, sender test relay i283, sender select magnet and, relay H92 and relay 768, also sender group test relay i953, and the remaining operated relays of Figs. '1 and 2, relay 228 releasing last.

Relay 62! releases following the release of relay .620 if no calls are waiting in other groups. When Relay" calls are Waiting in other groups, the corresponding group start relay, for example relay 652, is operated, grounding conductor 64!, which is common to all groups, and thereby holding relay 62! operated and preventing the extension of a new call in this group until other waiting groups have been served.

The junctor is now connected over the primary sender selector 438 and secondary sender selector 440 to the terminating sender.

Emergency operation of control circuit Before proceeding to a description of a call involving a B junctor, the operation of the link control circuit in connection with a mate frame will be described. When conductor 64! is grounded, this ground extends over the left back contact of relay 545 to conductor 55% and an interrupter (not shown). After an interval the interrupter grounds conductor 559, operating relay 553 which locks to conductor 558. After a further interval of about 6 seconds the interrupter connects ground to conductor 56!), completing a circuit over the right contact of relay 553 to the winding of relay 541 and battery. Relay 541 also looks to conductor 558, lights lamp 548, and operates relay 543 over the left contact of key 544. Relay 543 opens the operating circuits for relays 542 in both the home and mate control circuits and the circuit of relay 545 and transfers 7 the circuit of relay 546 from control by the sender relay and the release relay 228 to the transfer relays 550 of the home and mate frames.

In addition, relay 543 closes a circuit for relay 550 which is effective if the transfer relay 555 and start relay 552 of the mate control circuit are idle. The circuit may be traced from battery through the winding of relay 558, through rec'- tangle 350, over the outer left back contact of the mate relay 550, right back contact of mate relay 552, back through rectangle 353, to ground at the inner right contact of home relay 543. Relay 550 locks over its inner right contact to ground over key 55! and therefore remains operated until released manually by the operation of the key. Relay 553 further opens the circuit for mate relay 542, operates relay 546, lights lamp 549, extends the start circuit from the front contact of relay 552 to the winding of mate relay 545, and opens the circuit of mate relay 550.

Relay 542, if operated, releases, in turn releasing relays 555 and 350. The operation, of relay 546 disconnects ground from conductor 558, releasing relays 553, 541 and 543. When relay 543 releases, mate relay 545 operates, locking in- Timing for sender connection In the control circuit, relay 22! operates as soon as the control circuit is associated with a group of senders. Relay 221 at its inner right contact connects interrupter 222 to conductor 234, thereby grounding that conductor at half second intervals. Relays 2H) and 2H function in the well-known manner, relay 2 operating at the beginning of the first pulse and relay 2H] operating when ground is removed. Relay 2 releases at the beginning of the second pulse and relay 2I0 at the end, the cycle repeating as long as the ground pulses continue. If the control circuit has not released when relays 2H and 2H] have operated and relay 2]! has released, a circuit is closed from battery through the winding of relay 2l8, outer right back contact of relay 224, inner left back contact of relay 220, right front contact of relay 2), left back contact of relay 2! I, conductor 235, armature 623 of relay 600, conductor 625 to ground over the right contact of key 544. Relay 218 locks under the control of release relay 223. Relay 2l8 opens the circuit of relay I05, releasing the selected group of senders. Relay 2l8 also closes a circuit from battery through the winding of relay 223, left front contact of relay 2l8, left contact of relay 225, to ground at the right back contact of relay H5. Relay 223 also looks to the back contact of relay 228. In selecting a sender group, the preference lead coming into the control circuit over conductor 232, normally extends over the back contact of relay 218 to the armature of relay I 02. With relays. 2I8 and 223 operated this preference lead is extended over the front contact of relay 223 to the armature of relay IUD, thus endeavoring to seize a difierentsender group.

Relays 2H], 2H, 2l8 and 223 are. permitted to function if because of false grounds relay H1 operates as previously described, or if because the cross-points fail to close properly, relay 220 does not operate. If relay 220 operates, but because of double connections relay 2l5 does not operate, when relay 2 falls back, the circuit above traced to relay 2! 8 extends over the left front contact of relay 226 to the winding of relay 224, which looks under the control of relay 22l. Relay 224 closes a circuit from battery through the winding of relay 423, conductor 439, armature 32l of relay 355, inner right front contact of relay I00, middle left front contact of relay 224, to ground at the left back contact of relay 2l4. Relay 423 opens the circuits of hold magnets 424 and 425 opening the corresponding cross-points and disconnecting ground from relay 220, which releases. It also connects ground over its left contact, conductor 438, armature 322 of relay 30B, outer right back contact of relay 225, inner left front contact of relay 224, to the winding of relay H9 and battery. Relay 2I9 operates and locks under the control of relay 22L Relay 2l9 connects ground over its middle left contact, armature 323 of relay 35!], armature 194 of relay 150 to conductor 198 to release the sender. It also connects ground over its inner left contact, outermost armature of relay 340, armature 193 of relay 155 to conductor 191, which ground is passed back over conductor 15! and thence as previously traced to the winding of relay 220 and battery. Relay 220 closes a circuit for relay 2l8 over the outer left contact of relay 2l9, inner right and left contacts of relay 220 to the right front contact of relay 2l0 and thence to ground as described above when relays 2|!) and 2H reach the proper point in their cycle. Relay 2|8 functions as previously described to release the sender group selection relays and to bring about a second trial.

If the sender is selected and otherwise operates correctly but fails to send a release signal to the link Within the prescribed length of time, the functioning of relays 2H! and 2 will bring I group busy relays.

about the operation of relay 224 as described. If relays 226, 2I5 and 2M have been operated, when relay 2!!! releases after operating relay 224 it closes ground over its back contact, outer left front contact of relay 224, outer right front contact of relay 2I4, winding of relay 228 and battery. Relay 228 functions in the usual manner to release the link control circuit. If relays 226, 2I5 and 2I4 do not operate, the call is transferred to the mate control circuit.

Operation in connection with B iunctor When a call is originated on a junctor to be served by a B operator, the group start conductor is grounded in the same manner as by a full mechanical junctor. As above mentioned the B junctors are grouped together and will be served by individual links. Assuming the B junctor indicated in Fig. 4 is seized, conductor 45! is grounded, operating the individual group relay 652. The circuit for relay 652 may be traced from grounded conductor 45!, back contact of relay 65!, back contact of hold magnet 452, back contact of relay !3I, outer right back contact of relay 65!, contact of jack 65'! to the winding of relay 652 and battery. Parallel circuits are closed over the back contacts of the hold magnets of the other two links serving this group of junctors and the corresponding sender Relay I3! operates from relay I55 which, in turn, operates over the front contacts of relays H8 and H9 if the two B senders of this group are both busy.

Relay 652 grounds conductor 64! to start the operation of the control circuit in the usual manner. Relay 542 is operated, in turn, operating relays 666 and 366. Relay 652 now indicates the identity of the calling group of junctors to the group relays 526 to 529 by closing a circuit from ground at its middle right contact, armature 653 of relay 666, inner lower back contact of relay 536 to the winding of relay 526 and battery. Assuming'relay 526 is operated alone, it removes the operating battery from the higher numbered relays to prevent interference. It also extends its operating ground over its lower front contact and the back contacts of thehigher numbered group relays including relay 529, upper back contact of relay 5!!) to the winding of relay 54! and battery. Relay 526 also closes a circuit from ground over the upper back contacts of relays 529 and the intermediate group relays, outer upper front contact of relay 526, armature 654 of relay 666, to the winding of relay 655 and battery. Relay 655 performs the same functions for this group of junctors that relay 626 performed for its group. Since this B junctor is also the first in its group, relay 655 connects start lead 45! over armature 656 of relay 655, armature 665 of relay 666, inner lower back contact of relay 5!!) to battery through the winding of relay 566.

All of the trunk relays operate and lock temporarily as above described. With relays 566 to 566 operated a circuit'is closed from battery through the winding of relay 65!, armature 658 of relay 655, armature 666 of relay 666, left back contact of relay 546, inner upper front contacts ofirelays 566 to .569, inner left contact of relay 54! to ground at the middle lower front contacts of relays 566 to 569. Relay 65! looks under the control of relay 666 and opens the multiple ground allowing all relays but relay 566 to release. Relay 65! also releases relay 652 which closes the circuit of relay 546 over armature 668 of relay 666, armature 666 of relay 655,

left back contact of relay 652, armature 656 of relay 655, armature 669 of relay 666, outer lower front contact of relay 566 to ground over the operating circuit of that relay. Relay 546 supplies locking ground at its outer right contact in place of the ground supplied by relay 566.

Relay 566 operates relay 536, which in turn operates relay 5I6. Relay 546 also provides a holding circuit for relay 526, which extends over the lower front contact of relay 526 and the lower back contacts of the other group test relays, back contact of relay 529, middle left front contact of relay 546, armature 6! I of relay 666, armature 66! of relay 655, back contact of magnet 452, back contact of relay I3I, armature 662 of relay 655, armature 6I2 of relay 666 to ground at the third right contact of relay 546. As in the operating circuit of relay 652 there are parallel circuits over contacts of the hold magnets and sender group busy relays of other sender groups. In addition relay 546 also looks relay 566 as before.

With relay 5 I 6 operated the select magnets corresponding to relay 566 are operated as above described.

In the meantime the sender test is taking place.

ince this is a B junctor, group relay 655 connects ground over armature 663, armature 664 of relay 666, conductor 665 to the winding of relay I32 and battery. With relay I32 operated the three sender groups are tested to determine whether the links are idle and B senders are available. The test circuit for the group shown extends from ground at the left back contact of magnet 452, armature 666 of relay 655, armature 6I5 of relay 666, conductor 6! 6, outer right back contact of relay 22!, right winding of relay I66, right back contact of relay IZ'I, outer left contact of relay I52, armature 33! of relay 366, conductor 332, outer right contact of relay I62, left back con,- tacts of relays E55, M8 and M9 to battery. This is under the assumption that the two B senders of the group to which relays H8 and H9 belong are idle. If one of the senders were busy and the corresponding sender busy relay operated, this circuit could not be completed. If both senders were busy relay 655 would be operated over the middle left front contacts of relays H8 and H9, in turn, operating relay 13 I.

Similar test circuits are closed for relays I6! and I62. With at least one sender busy in each group, the regular test would fail and the reserve test he made under the control of relay !2!. The reserve test circuit for relay I 66 extends over the outer right front ccntact of relay I21, inner right contact of relay I32, armature 333 of relay 366, conductor 334, inner right back contact of relay 762, to battery at the right back contact of relay I55. If both senders are busy so that both tests fail, this group of senders cannot be used.

Assuming, however, that the reserve test is successful, relay H8 being operated but relay H9 idle, relay I66 will operate, in turn, operating relay I65, which provides a locking circuit for relay I66, and an operating circuit for relay 22!. Relay I65 also operates relay I62.

With relays I66 and I65 operated, relay I56 is operated as previously described. Relay I56 closes a circuit from battery through the winding of relay T58, armature 765 of relay I56, conductor I86, armature 3I5 of relay 366, outer right contact of relay I32 to ground. Relay I58 closes a sender selecting circuit from ground at the inner right front contact of relay 546, middle upper front contact of relay 566, conductor 55!, armature 3I6 of relay 666, conductor 3II, armature 18! of relay ldtt inner right contact of relay 158 to the outer right armature of relay 7 l 8. Since it was assumed that relay H8 is operated, the circuit extends over the outer right front contact of relay H8, right back contact of relay H9, winding of relay i228 and battery.

Relay i233 locks to ground on armature 732 of relay 75d, and connects ground to the winding of relay m2. It also closes a circuit from ground over the left back contacts of relays 120 to 128, outer left front contact of relay 129, armature E3? of relay 75B, conductor F38, winding of sender select magnet W9 and battery. A branch of this circuit extends over conductor 142 to the sender.

At its middle right contact relay 12!! connects ground to the circuit of relay 225, which operates relay lit as previously described. With relay H6 operated, a circuit is closed from ground at the inner right back contact of relay 224, inner right front contact of relay I I6, through the winding of relay 2E5 shunted by the outer left back contact of relay 220, middle right front contact of relay lilii, conductor 6H3, armature 6|! of relay 6B0, armature 651 of relay 655, outer right back contact of relay 423 to the windings of hold magnets 4 ,52 and 45 5. These magnets close the crosspoints prepared by select magnets 453 and 409, completing the connection between the junctor and sender.

The testing of this connection and the release of the control circuit take place in the same manner as for a full mechanical junctor.

What is claimed is:

1. In a telephone system, a terminating oifice, trunk circuits incoming to said ofiice from manual ofiices, registering devices for association with said manual trunk circuits, trunk circuits incoming to said office from dial oilices, registering devices for association with said dial trunk circuits, and a unitary switching device for connecting any one of said trunk circuits with one of the corresponding registering devices.

2. In a telephone system, a terminating ofl1ce, trunk circuits incoming to saidofiice from manual ofiices, registering devices for association with said manual trunk circuits, trunk circuits incoming to said ofiice from dial oilices, registering devices for association with said dial trunk circuits, and a unitary switching device responsive to seizure by any one of said trunk circuits to connect said trunk circuit with one of the corresponding registering devices.

3. In a telephone system, a terminating oflice, trunk circuits incoming to said ofiice from manual offices, registering devices for association with said manual trunk circuits, trunk circuits incoming to said office from dial ofiices, registering devices for association with said dial trunk circuits, a unitary switching device, means for seizing said switching device by any one of said trunk circuits, means associated with said switching device to record the type of said trunk circuit, means for testing said registering devices, and means under the control of said recording means to cause said testing means to test only those registering devices corresponding to said trunk circuit.

4. In a telephone system, a terminating ofiice, trunk circuits incoming to said office from man-. ual oifices, trunk circuits incoming to said oifice from dial oifices, first registering devices for association with said manual trunk circuits, other registering devices for association with said dial trunk circuits, said registering devices being arranged in groups containing both said first registering devices and said other registering devices,

a unitary switching device, means for seizing said switching device by any one of said trunk circuits, means associated with said switching device to record the type of said seizing trunk circuit, a testing circuit associated with said switching device for testing each of the registering devices of a group, and means under the control of said recording means for rendering only those testing circuits efiective which test registering devices associable with the seizing trunk.

5. In a telephone system, a terminating ofilce, trunk circuits incoming to said office from anual oflices, trunk circuits incoming to said oihce from dial oflices, first registering devices for association with said manual trunk circuits, other registering devices for association with said dial trunk circuits, said registering devices being arranged in groups containing both said first registering devices and said other registering devices, a unitary switching device, means for seizing said switching device by any one of said trunk circuits, means associated with said switching device to record the type of said seizing trunk circuit, means for testing said registering devices comprising a set of relays one for each registering device in the group, and means under the control of said recording means for rendering only those relays eifective which test registering devices associable with the seizing trunk.

6. In a telephone system, a terminating ofiice, trunk circuits incoming to said ofiice from manual offices, trunk circuits incoming to said office from dial offices, first registering devices for association with said manual trunk circuits, other registering devices for association with said dial trunk circuits, said registering devices being arranged in groups containing both said first registering devices and said other registering devices, a unitary switching device, means for seizing said switching device by any one of said trunk circuits, means associated with said switching device to record the type of said seizing trunk circuit, means for testing said registering devices comprising a set of relays one for each registering device in a group, and means for operating one of said relays under the joint control of said recording means and the registering devices under test.

7. In a telephone system, a terminating ofifice, trunk circuits incoming to said ofiice from manual o-fiices, trunk circuits incoming to said office from dial oilices, first registering devices for association with said manual trunk circuits, other registering devices for association with said dial trunk circuits, said registering devices being arranged in groups containing both said first registering devices and said other registering devices, a unitary switching device, means for seizing said switching device by any one of said trunk circuits, means associated with said switching device to record the type of said seizing trunk circuit, means for testing said registering devices comprising a set of relays one for each registering device in a group, and means for operating a particular one of said relays under the joint control of said seizing trunk, said recording means and the registering device under test.

8. In a telephone system, a terminating oifice, trunk circuits incoming to said oflice from manual offices, registering devices for association with said manual trunk circuits, trunk circuits incoming to said ofiice from dial omces, registering devices for association with said dial trunk circuits, a unitary switching device, comprising primary and secondary cross-bar switches and links interconnecting them, sets of contacts in said primary switches and links individual to each type of trunk, sets of contacts in said secondary switches individual to each type of registering device and accessible to both types of link, and means for preventing links of one type from engaging contacts belonging to registering devices of the other type.

9. In a telephone system, a terminating ofiice, trunk circuits incoming to said office from manual ofiices, registering devices for association with said manual trunk circuits, trunk circuits incoming to said ofiice from dial offices, registering devices for association with said dial trunk circuits, a unitary switching device, comprising primary and secondary cross-bar switches and links interconnecting them, sets of contacts in said primary switches and links individual to each type of trunk, sets of contacts in said secondary switches individual to each type of registering device and accessible to both types of link, and means for permitting links of one type to engage only contacts belonging to registering devices of the same type comprising means for recording the type of an incoming trunk, means under the control of said recording means for testing only the corresponding type of registering device, and means under the control of said testing means to prepare a set of secondary switch contacts.

10. In a telephone system, a terminating ofiice, trunk circuits incoming to said ofiice from manual ofiices, registering devices for association with said manual trunk circuits, trunk circuits incoming to said ofiice from dial offices, registering devices for association with said dial trunk circuits, a unitary switching device, comprising primary and secondary cross-bar switches and links interconnecting them, sets of contacts in said primary switches and links individual to each type of trunk, sets of contacts in said secondary switches individual to each type of registering device and accessible to both types of link, and means for permitting links of one type to engage only contacts belonging to registering devices of the same type comprising means for recording the type of an incoming trunk, a set of relays for testing each group of registering devices, means under control of said recording means for preparing the circuits of those test relays only which test the corresponding type of registering device and means under the control of said test relays to prepare a set of secondary switch contacts individual to a registering device of corresponding ype.

WARREN W. CARPENTER. ALFRED E. HAGUE.

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