Patent GB-133343-A (GB)
IPC: H04Q3/42
Abstract: 133,343. Western Electric Co., and Polinkowsky, L., (Western Electric Co., partly). Jan. 25, 1918. Semi-automatic exchange systems.-Relates to registering and controlling equipments, particularly for semi-automatic B-operators, in which two or more registering sets comprising relays only are associated with a single set of number keys. Special provision is made for " translating " from one numerical system to another, as required in systems using 200-point selectors, and for controlling the length of time the fundamental circuit is kept open at the register between successive selecting operations. The invention is described as applied to a system in which calls are extended from an A-operator's position, shown to the left of Fig. 1, through a semi-automatic B-operator's position to a subscriber on a 2000-line satellite, Fig. 4, connected to the main exchange by a two-wire trunk 230. On the receipt of a call over an order-wire, the B-operator assigns the junction to be used and depresses the assignment key 201 individual to that junction. Connexion of idle register set to selected junction. The operator has a single keyboard with two registers, preference being given to the A- register if idle. The A-register is shown in detail in Figs. 2 and 3, the B-register being indicated in Fig. 2 only by the relays 371 - - 374, which operate in the same way as corresponding elements in the A-register. Assuming that both are idle, the depression of the assignment key 201 closes a circuit through the lefthand winding of relay 202, key 201, wire 220, and back contacts of relays 303, 371, to ground. Relay 202 completes a holding-circuit through its right-hand winding and relays 205, 304, and closes a circuit over an interrupter 212 for the calling and guarding lamps 206, 207, while relay 205 prepares the fundamental circuit for the trunk 230 over wires 221, 223 and the stepping- relay 307, this circuit being completed when the relays 208, 308 are energized as described later. Relay 304 energizes relays 303, 309, relay 303 opening the circuit for seizing the A-register, while relay 309 energizes the holding-magnets 411 of the operator's keyboard. If the B-register had been in use, and the A-register idle, the initial energizing-circuit for relay 202 over wire 220 would have been completed over the contacts of relays 372, 373 as soon as the keyboard was disconnected from the B-register. The wiring between the A and B registers is so arranged that, by a slight change, preference may be given to the B-register instead of to the A-register. Operator's keyboard and register sets. The operator registering and controlling equipment comprises relays only, which are used for registering the number, counting the reverting-impulses, producing the necessary circuit changes between successive selection-controlling operations, and introducing a timed delay between such operations. Fig. 3 shows the thousands, hundreds, tens, and units keys with their connexions to the A-register, the duplicate connexions to the B-register not being shown. The number relays 412, 413, 414, Fig. 3, are connected to the units, tens, and hundreds keys as shown, the thousands keys not being provided with number relays, since, in the case assumed, the capacity of the satellite does not exceed 2000 lines. One number relay is provided for each units and tens key and for each pair of hundreds keys. As the selectors used are 200-point switches with ten levels, each containing twenty sets of terminals, translation is necessary and is effected partly by the number relays and partly by the set of counting-relays. The method of wiring the group and final selectors is such that, when the thousands digit is odd (1 in the special case described), connexion is made to the odd levels of the group-selector, and when it is even, to the even levels, consecutive levels containing terminals of final selectors serving lines having the same hundreds digits but different thousands digits. For example, the first level of the group-selectors may lead to final selectors serving the group of lines 1000-1199, while the second level leads to selectors serving the group 2000-2199. It is necessary therefore that the tripping-spindle of the group-selector should rotate one step less when the thousands digit is odd than when it is even, and this is effected by an arrangement whereby one pair of counting-relays is short-circuited when an odd thousands key is depressed. Tens selection proceeds without translation, but as each level of the final selectors contains twenty sets of terminals, ten of an even hundred and ten of an odd hundred (e.g. one level may contain lines 210 to 219 and 310 to 319), it is necessary that, when the hundreds digit is odd, the final selector brushes must rotate through ten extra steps, and, to effect this, it is arranged that the depression of an odd hundreds key causes the train of counting-relays to run through a complete cycle in addition to the number of steps determined by the units key. Registration of wanted number on register. The relays 303, 304, 309 having been energized as previously described, the operator depresses keys 415 - - 418 corresponding to the wanted number, say 2222. The corresponding number relays 472, 413, 414 are each energized in series with the common units, tens, and hundreds relays 321, 322, 323, Fig. 2, and the relay 324 is energized in series with the depressed thousands key 418, The number relays lock up over the left-hand armatures of relays 321, 322, 323, and the relays 321 - - 324 close u circuit for relay 313 over their series contacts and relays 314, 315. Relay 313 provides a locking-circuit for the right-hand windings of relays 321 - - 324 in parallel, including relay 305, which opens the circuit of the holding- magnets 411 of the keyboard and earths the common test wire 224 of the B-register, so that this can be taken into use. Relay 313 also closes the circuit of a relay 312, which energizes relay 308 to prepare further the fundamental circuit, including the stepping-relay 307. At this stage, the relays 202, 205, 303, 304, 305, 308, 309, 312 - - 315, and 321 - - 324 are all energized, as well as the number relays 412. 413, 414, whereas the keyboard is released for use with the B- register. Operations from the insertion of the plug by the A-operator. The fundamental circuit is open at the contact of relay 208, so that selection cannot proceed until the A-operator inserts the plug in the jack of the assigned junction, thereby energizing relay 209. To prevent the possibility of false impulses in the fundamental circuit due to faulty insertion of the plug, it is arranged that the relay 208 is energized over the right-hand armature of relay 209 and the tip of the plug. Relay 208 closes a holding-circuit over both its windings in series, both armatures of relay 209, and relay 211, which disconnects the guarding-lamp 207. The calling-lamp 206 alone is flashed during the selecting-operations. Controlling operations of register. It will be convenient to describe first the operations when the thousands and hundreds digits of the wanted line are both even, in which case the special translating-arrangements associated with the hundreds and units selection do not come into use. The set of relays 314 - - 317 serves primarily to introduce a timed delay between successive selecting operations, and the relays 331, 333 serve to bring the counting-relays 325, 326, 327, &c. under control of the hundreds, tens, and units keys successively. Assuming that line 2222 is to be called, the stepping-relay 307 closes a circuit from the grounded armature of relay 316, armatures of relays 307, 331, wire 428, right annature of hundreds relay 414, and counting-relay 325, to battery. Relay 325 locks up over relay 335, which is short-circuited until the stepping- relay 307 is de-energized, when relay 335 is energized and prepares the circuit of relay 326. The counting-relays are energized in pairs in the usual way until the last pair of relays 319, 338 is reached, when relay 319 opens the fundamental circuit to make the necessary circuit changes at the .group-selector, while relay 338 closes a circuit through relay 332 and a slow-acting relay 316. Relay 332 locks up over a relay 331, which, however, is shunted by the low-resistance relay 316 and remains de-energized, while relay 316 short-circuits relay 315, which closes a circuit for the left winding of relay 318 and relay 317 in parallel, over the right armature of relay 324 and the armatures of relays 305, 309. Relay 317 short-circuits relay 314, which opens the holding-circuits of the counting-relays, including relays 319, 338. Relay 338, which is timed to close its back contact after all the counting-relays have de-energized, opens the shunt around relay 331, which energizes and extends the circuit controlled by the stepping-relay to wire 429 instead of wire 428. Relay 316 de-energizes, removing the shunt around relay 315, which in turn de-energizes relay 317, thus re-energizing relay 314 to prepare a holding-circuit for the counting- relays. Thus, the timed interval between the running-down of the counting-relays and the reestablishment of the holding-circuit is determined by the temporary energization of relays 316, 317 and de-energization of relays 314, 315. As two of these relays are slow to operate, and the other two are slow to de-energize, the interval is independent of variations in the battery voltage. The relay 318, which was energized in parallel with the relay 317, disconnects the stepping-relay 307 from the trunk circuit, and connects thereto battery and a relay 342, this change taking place after the sequence switch of the group-selector, Fig. 4, has connected a relay 516 across the incoming end of the trunk 230 as described later. Relay 342 is energized over this circuit and closes a holding-circuit over the righ