Patent GB-303929-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/42
Filed: 1927-10-14
Abstract: 303,929. Automatic Telephone Manufacturing Co., Ltd., and Ostline, J. E. Oct. 14, 1927. Addition to 265,653. Automatic exchange systems.-A register-controller taken into use from a first code selector comprises a hunting switch which connects it to an A-digit, Strowger-type switch, and the exchange digits operate the A-digit and the B.-C. digit switch to select an impulse sending switch, individual to the required exchange, from which translated digits are sent in batches simultaneously by impulses over separate wires to the controller. The translated digits and the numerical dialled digits are recorded on uni-directional switches which control the sending of routing digits. The impulse-sending switch is. a singlemotion five-wiper switch, over one wiper of which the switch is stepped continuously through its bank, over three others, impulses are sent simultaneously in two sets separated by a pause, and over the fifth, circuit changes are made to switch from one set of registers to another between sets of digits. For calls to an operator, enquiry or the like, a special impulse-sender is reached having means for releasing the controller when the routing digits only have been sent. Arrangements are made to deal with premature or delayed dialling accidental impulsing, dialling of wrong code digits, faulty impulse springs in the register-controller, and excessive hunting time during routing of the call. If there is no outlet from the A-digit switch, a congestion meter is operated. If a subscriber does not hang up when he hears busy tone, this is changed by a time-pulse relay to N.U. tone to indicate that the apparatus is released. Seizure of register controller . When an idle first code selector, Fig. 3, is reached, relay L1 and guard relay B are operated in turn. Relay A energizes in series with an energizing circuit for relays C, MD in paral- ]el. The register-controller selector RCS, Fig. 4, now hunts (DM1, 81, 63, 50, 29, 78, private wiper, 75, 39, 36); on engaging a, busy register, DM1 is maintained energized by earth over conductor 86. On finding an idle register RC, Fig. 5, relay K1, previously short-circuited, is energized and relay BA pulls up, and an alternative circuit is formed for relay B. Impulse-accepting relay A1 or RC now operates over conductors 84, 76, and armatures 58, 25, low resistance winding or M, armature 22, and relay B1 pulls up over busy Key 150, maintaining K1, Fig. 3, energized by a busy earth, starting the motor-drive, and lighting the supervisory lamp. Relay A, Fig. :3, is held in a circuit over its lower winding, conductors 79, 83, 175, to battery over armature 248 in the register selector, Fig. 7. Seizure of digit registers. Relay S, Fig. 7, of the registerselector RS operates [earth on key 150, armature 135, 150, 146, conductor 168, 244, S, battery]. It RS is on a, busy A-digit switch ADS, earth on wiper 267, from armature 259 of the register selector associated with the busy ADS, energizes magnet DM2 to find an idle ADS, when relay K2 previously shorted, is ener- .gized in series with DM2, and relay B2, Fig. 8, also energizes. When B1 operated, relay LC pulled up over its upper winding to operate armature 115 (earth, key 150, 135, 103, 116, 124, 117, LC, battery) and then fully over both windings, when loop pulse springs 124 open, after which two-step relay CC operates similarly over pulse springs 89. Subscriber dials exchange digits. Dial tone relay DT, Fig. 5, operates and dial tone is sent over the b-wire from conductor 157. Impulses are repeated via relays L1, Fig. 3, A1, Fig. 5, to the vertical magnet VM1 of switch ADS via wiper 190 of digit distributor switch DD, in series with relays C2; relay C1 of RC energizes in parallel therewith and closes a circuit for digitstepping relay DS. Owing to closure of off-normal springs 289, relay E1, Fig. 8, energizes, and locks over interrupter spring of rotary magnet RM1. When relay C2 restores, RM1 operates to step on to the first BC digit switch, releasing E1. Relay E1 releases RM1 in turn, but will operate again to earth on wiper 391 if the BC switch is busy to step ADS on again. On reaching a free BC switch, switching relay K3 energizes [earth, 274, 284. upper winding of K3, 290, interrupter springs 289, E1, which does not operate, battery]. Release of relay C1 at the end of the digit closes a circuit for the stepping magnet of DD, owing to relay DS being slow-release. DD steps to its second contacts, releasing relay DT. The second digit operates magnet VM2 of B.C.S. in series with relay C3; relay E2 operates its armature 298 over its lower winding and energizes fully when, C3 restores, switching the pulsing lead through to magnet RM2. Relays C1, DS again operate during dialling, and switch DD is now stepped to its third contacts, and the third digit operates magnet RM2 in series with C3. Relay AK first operates its armature 312, and when C3 releases, operates fully over wiper 291. Switch DD is again stepped on to its fourth contacts, connecting the pulsing lead to the stepping magnet df first numerical register switch NR1. Registration, of numerical digits. These digits operate in turn switches NR1 - - NR4, switch DD Stepping on between each digit. Registration of exchange code digits. When the B.C. switch is set, it is connected to a code selector switch CSS, Fig. 10, and switching relay K4 operates over its lower winding in series with relay S1, Fig. 10, and then energizes fully, releasing relay AK. Magnet DM5, Fig. 10, operates to step CSS when relay S1 releases, and impulser TM is energized over the strapped contacts of wiper 324, causing relay IR to impulse magnet DM5. The wipers 320, 322, 323 of CSS pass over four dead contacts before reaching contacts intermittently earthed as shown to send impulses in accordance with the first three code digits corresponding to dialled exchange to relays PA, PB, PC, Fig. 7, which repeat them to the stepping magnets of code register switches CR1 - - CR3, Fig. 6. When the. wipers of CSS reach the 14th contacts, the last impulse is sent to switch CR2, an impulse is also sent over wiper 319 to energize relay UD, Fig. 7, momentarily. Relay K5 operates partially, and pulls up p completely, when PD releases, to earth on conductor 161, releasing relay CC in the registercontroller, and switching the impulsing leads from switches CR1 - - CR3 to CR4 - - CR6. Only four code digits are required in the example shown, and the fourth digit is now sent via wiper 317 to CR4, the other code-registers remaining at normal. Relay PD again operates momentarily to operate two-step start relay ST. Relay CC is now energized partially over pulse springs 89, and pulls up fully when the springs break from earth a.t 249. Upper winding of CC, 173. 170, 126, lower winding of CC, 123, to earth at key 150. Release of switches A.D.S. and B.C.S. Operation of relay ST, releases relays S, .K2, Fig. 7, B2, Fig. 8, in turn; relays K3, E2 then release and the switches A.D.S., B.C.S. return to normal. Transmission of digits from registers. The driving magnet DM3 of sender switch SS is now given ten impulses per second by springs 89. Relay A, Fig. 3. is now held in a loop over shunt field relay D1 in RC, 138, 183, 248, 175, 91, until start relay SA energizes over the first contact of wiper SS (148), which connects loop-springs 124 across conductors 83, 85 to relay A. The loop and magnet springs 124, 89 operate in unison, so that an impulse is sent to relay A for each step of SS until stop relay SZ energizes over the connected contacts of wipers SS (149), CR1 (195), and locks up, short-circuiting the loop springs. releasing relay CC, and forming a homing circuit over wiper SS (148) for the sending switch. When SS reaches normal, relays SA, SZ restore slowly in turn, and relay A is again held over relay D1. Magnet DM4 of sender control switch SO, Fig. 6, energized during the operation of relay SA, now releases, stepping SC to its second contacts. Relay CC now pulls up as before, connecting the springs 89 to DM3, impulsing taking place as before, governed, however, this time by the position of wiper CR2 (196). Relay SZ again operates, switch SS is returned to normal, and switch SC stepped to its third contacts. The remaining code impulses are sent out in accordance with the setting of register switches CR3, CR4. Switch SC is now stepped in turn over wipers CR5 (190), CR6 (200) to its seventh contacts. Impulsing is again begun, and digits are sent in the 7th - - 10th positions of SC in accordance with the setting of registers NR1 - - NR4. The operation of relay CC to initiate the sending of the thousands digit is dependent on the dialling of the hundreds digit, the circuit therefor being over wiper 185 and wiper 234 of switch NR2 when off-normal. Similarly the hundreds and tens digits are not sent out until the tens and units digits are dialled. The ninth and tenth contacts of wipers 185 are strapped so that relay CC operates to initiate the units digit. SC is now on its 11th contacts, and cut-off relay CO operates from earth at 249, and locks up to earth at key 150, releasing relays LC, B1, making RC again available. The switches SG, DD, and the register-switches are now homed in circuits including relay RA, so that if any switch does not return to normal, RA operates an alarm over 153. Setting-up of connection. The first digit sent to relay A. Fig. 3, operates the vertical magnet VM of FCS, relay C being maintained operated in parallel therewith. Relay E operates over rotary impulse springs 53, and vertical off-normal contacts 70, and when relay C releases, rotary magnet RM operates, releasing E, which releases RM in turn. If the first junction reached in busy, earth on wiper 74 re-operates relay E and the switch is stepped on until an idle junction is found, when switching relay H previously short-circuited energizes, cutting out relay A, and the r