Patent GB-263909-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/42
Filed: 1925-09-09
Abstract: 263,909. Automatic Telephone Manufacturing Co., Ltd., (Automatic Electric Co.). Sept. 9, 1925. Automatic exchange systems. - A registercontroller seizes an idle office register and releases it as soon as the translated exchange code has been transmitted. The office register OR, Fig. 4, sets its wipers on terminals jumpered to the wipers of a code drum 301, a single drum and jumpering-frame being common to all the registers. Each digit is transmitted by the drum 301 to the register-controller as a signal consisting of one. two or three elements from a succession of four impulses + - + -, which operate a polarized relay 235, Fig. 3, to energize a particular combination of the relays A - - D, Fig. 5. For example, if the wipers 339 - - 342 are set on the terminals 331 - - 334 the first digit is controlled by the No. 9 code wiper 319 which sends over the wiper 339 only the third impulse of the above series, which energizes only the relay C, which grounds the No. 9 stop wire of the sending switch SS. When the switch SS has sent out the digit 9 the drum 301 signals the second digit over wipers 312, 340, and so on. Signals indicating that a digit is to be skipped, or that the connection is to be switched through immediately (as when the call is for an operator) are sent bv similar codes. Seizure of idle register-controller and office register; recording dialled digits. When the switch RS. Fig. 1, seizes a register controller, relay 240, Fig. 3, is energized to ground the wire 203 and to join the wires 201, 202 so that the switch ORS, Fig. 5, hunts for an idle office register OR, Fig. 4. Relay 402 is then energized and dial tone is sent back over circuit 307, 351, 121, 32, 33, 7. The first digit is repeated by relay 8 over circuit 32, 121, 351 to the vertical magnet 343 of the office register, the second digit to the rotary magnet 344, and subsequent digits to the registers DR1 - - DR4, Fig. 6, the switch S, Fig. 2, being stepped forward at the end of each digit when the series relay 101 relapses. Transmission of translated exchange designation. As soon as the two exchange digits are recorded, battery is connected by the switch S to wire 208, and when the drum 301, Fig. 4, next passes its zero position a pick-up circuit 216 energizes relay 232, Fig. 3, which locks up in series with relay 238. The first wiper 339 of the office register is now connected over circuit 355, 127, 209 to polarized relay 235, the other terminal of which is connected to half-battery potential, so that this relay is thrown from its neutral position in one or other direction, to close one of the contacts 272, when the drum 301 connects battery or ground to the wiper 339. In position A + of the drum 301 ground on the circuit 355 causes the polarized relay to energize relay A, Fig. 5, over circuit 210, but in positions B - and C + a circuit 214 is closed to energize relay 233, so that in position C + ground on circuit 355 results in the energization of relay C over circuit 212. Similarly, battery on circuit 355 energizes relay B in position B - but relay D in position D-, because relay 234 is energized over circuit 215 in positions C + and D -. Thus a combination of the relavs A - - D is energized dependent on which of the drum wipers 311 - - 320 is jumpered to the terminal selected by wiper 339. The energized relays lock to circuit 217 and connect ground to one of the ten stop wires of the sending switch SS, Fig. 3. The next closure of the pick-up circuit 216 energizes relay 239, Fig. 3, which locks itself to circuit 217, opens the pick-up circuit, unlocks relays 232, 238 and closes a circuit 115, 118, 274, 245 to step the sending switch SS and to interrupt the outstepping circuit 29, 30 at contact 243. When the wiper 247 reaches the grounded stop wire, relay 242 is energized, locks itself, shunts the impulse contact 243, closes a self-interrupting quick-return circuit for the switch SS, takes ground off the circuit 217 to unlock relays 239 and A - - D, and opens a circuit 207 (previously closed by relay 241) to de-energize magnet 110, Fig. 2, which steps the switch S<1> to its second position, in which the second wiper 340 of the office register is brought into circuit to control the transmission of the second digit. When the switch SS regains its normal position, relays 241, 24.2 relapse and the circuits are ready to deal with the second digit as soon as the drum 301 next passes its zero position. The remaining digits, up to a total of four, are sent in the same way, and the switch S<1> is brought to its fifth position. If only two or three digits are required the terminal engaged by the third or fourth wiper of the register is jumpered to wiper 306 of the drum 301, with the result that relays A, B, C are energized and close the circuit 206 of relay 114, which disconnects the driving circuit of the sending switch and drives the switch S<1> at once to its fifth position. Release of office register: transmission of remaining digits. In the fifth position of the switch S<1>, relay 231, Fig. 3, is energized over circuit 205, locks itself, grounds circuit 204 to energize the release magnet 345 of the office register takes ground off circuit 203 so that relay 402, Fig. 5, is released as soon as contact 346 is opened by the restoration of the office register, opens circuit 217 to unlock the relays A - - D, and grounds the circuit 209, 131 leading to the wiper of the register DR1. ' The remaining digits are then transmitted under control of the registers DR1 - - DR4. The sending switch is driven over a circuit 115, 118, 250, 292; relay 242 is energized when the switch reaches a ground stop wire; and switch S<1> is stepped forward after each digit to bring the next register into circuit. Operation of the sending switch before the appropriate register has been set is prevented by connecting the home contacts of the registers to a circuit 219 to energize relay 242, which opens the driving circuit at contact 292 until a definite interval after the starting of the register. Release of register-controller. The switch S<1> in its final position grounds circuit 32 to energize relay 10, Fig. 1, which locks itself, switches through, and disconnects the register-controller. The removal of ground from circuit 31 unlocks relay 240 which grounds circuits 205, 218 to advance the switch S<1> to normal and to release the registers DR1 - - DR4 and the switch S. Connection to operator. A call for an operator sets the office register on a set of terminals 335 - - 338 which are jumpered so as to cause three digits to be sent and the connection immediatelv afterwards switched through. The fourth terminal 338 is jumpered to the wiper 305 of the drum 301, which sends a code signal to energize relays A, B, D, Fig. 5, which ground the circuit 32 to energise the switching relay 10, Fig. 1. The relay 240 is de-energized and releases the register-controller and the office register. Two modifications are described for reducing the number of wipers in the switch ORS by controlling the magnets of the office register over circuits subsequently used for transmitting code signals. In the arrangement shown in Fig. 8, the energization of relay 402 grounds the circuit 354 of a two-step relay 701, which only pulls up its armatures 703, 704, its lower winding being short-circuited over 356, 128, 606, 108. The two exchange digits are sent over circuits 121, 130, 358 and 122, 129, 357 to the vertical and rotary magnets 343, 344, and the switch S then moves to its third position, removing the short-circuit from the lower winding of relay 701 which pulls up its remaining armatures so as to connect the circuits 128, 129, 130 to the. wipers 340, 341, 342. When the office register is to be released the relay 402 is de-energized and de-energizes relay 701, which closes the circuit of the release magnet 345 and grounds the test wire 354 until restoration is complete.