Patent GB-337453-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/00
Filed: 1929-08-01
Abstract: 337,453. Automatic Telephone Manufacturing Co., Ltd., and Taylor, R. Aug. 1, 1929. Automatic exchange systems.-In a system for working between step-by-step and revertive impulse exchanges, a register controller is, employed at the step-by-step exchange which is preselected from an idle junction to the revertive exchange and in which the following features are provided : (i) the dialled impulses are stored on registers whose wipers place a selectable potential on a. marking wire, certain of the registers exerting a different control on the switches to be set dependent on the setting of preceding registers at the time that the control is being exerted (ii) revertive impulses are revived on an impulse counter and the switch being set is stopped when the wiper of the impulse counter reaches the marked contact; (iii) two relay sets are provided, one of which distributes the dialled impulse series and the other connects the marking potential in turn over the storage registers to the impulse responder banks. General operation. On a call outgoing to a revertive impulse type exchange a trunk relay group TRG is seized and the outgoing loop is extended over a pre-selecting line switch PLS to the register-controller Figs. 2, 3, 4. The dialled impulses are stored on registers DR, distribution of the digits being controlled by relays 1A.-ID. As each impulse series is received, the next switch in the train at the distant exchange, Fig. 5, seized over junction 152, 153, is allowed to operate and send back impulses to which switch SS responds. When wiper 326 of SS reaches the terminal marked by the digit register wiper, the loop is broken to stop the seized switch and the marking potential is passed on by relay set OAOD to the next register. The hundreds and units registers are provided with two marking banks, the two wipers marking different terminals for each switch setting, and the marking used is dependent on whether the wipers of the thousands and hundreds registers respectively are standing on odd or even terminals at the time when the switch SS is hunting for the marked wire. Release of the register-controller is described in cases of premature release and of delayed dialling when the revertive exchange seized is of either of the following types - (i) those in which the switches during setting are held from the register controller, and (ii) those in which the switches are held during setting in a local circuit. Seizure of register-controller : recording of dialled digits. When the relay group TRG is seized A operates followed by B and TK, and in the register controller AZ and BZ pull up. Relays A and AZ respond to the first impulse train, and the digit is repeated to magnet 301 of register DR1000. Relays SR and C operate on the first impulse and hold up over the train, and relay 1A operates its light armature 246, operating fully and locking up when C releases. Relay 1A transfers the input circuit to magnet 302, and when the next digit is received magnet 302 steps register DR100 a. corresponding number of steps. When this train ceases 1B operates fully and the next series is recorded on DR10. Similarly 1C transfers the circuit for the last digit to be recorded on register DRU. Setting of switch train. When the first digit has been recorded relay 1A operates fully and at armature 244 a loop is completed through relay RC to the distant exchange. RC operates in series with GLR (Fig. 5) and completes a circuit for magnet 305 of SS, the wipers of which move on release. At. the distant exchange relay GLR operates and moves the sequence switch into position 2, to complete a circuit for the trip spindle magnet. The trip spindle commences to rotate, and at each step its interrupter I2 short-circuits relay RC, Fig. 2. The switch SS is stepped at each release of RC, and when its wipers reach the terminals marked bv wiper 314 of DR1000 a circuit is completed for relay SZ which re. places the loop across the circuit by battery and earth. Relay GLR (Fig. 5) releases, relays HC (Fig. 2) and BGR (Fig. 5) operate in series and HS pulls up. When SZ pulled up OA operated its light armature 421 and a homing circuit was completed for SS over its wiper 324. When SS regains its normal position OA operates fully, transferring the marking earth from the thousands to the. hundreds register through wiper 312. which places the earth on wiper 317 or 318, dependent, on whether the thousands wiper 312 is standing on an even or odd terminal. The two marking wipers 313, 314 of DR1000 provide a discriminating marking for the thousands digit if the switch setting at the distant exchange depends on the value of an earlier digit. When the switch at the distant exchange has successfully extended the connection to the next switch of the train, earth is connected to conductor 153 releasing HC, whereupon HF energizes and opens a locking circuit of SZ. A parallel locking circuit runs through contacts of IB, and if the second digit has by this time been completely recorded, 1B would have beenoperated and SZ releases replacing RC across the outgoing junction. The next series of revertive impulses is received, and SS moves until SZ again operates (326, either 317 or 318, 312 to earth at 212). The tens and units digits are controlled in a similar way, the relay set OAOD connecting the marking earth from 212 in turn to the register sets. The units digit consists of a number between 1-10 or 11-20, the setting being dependent on whether wiper 323 or 322 is used as the control wiper, which is determined by the terminal on which wiper 316 of DR100 is standing (odd or even). Release of register-controller. When the final selector has been completely set relay CD, Fig. 4, operates fully and' allows JK to pull up. TR energizes, disconnecting the trunk from the register-controller and connecting it with the calling loop. Relay AZ releases and BZ falls back, opening the locking circuits of 1A-1D and OAOD. C pulls up between the release of AZ and BZ. and remains energized until the register controller has restored. When RZ releases an interrupter circuit is completed for magnet 301 in series with relay BP and wiper 311 and switch DR1000 is moved to one of its home positions. In this position a homing circuit is completed for magnet 302 to drive DR10G, and when this switch has restored the circuit is extended to DR10 and then to DRU. When all the switches have restored C and BP release. Completion of connection. When the called subscriber replies S3r (Fig. 5) operates, shorting. at 503, the high resistance winding of BGR and enabling D (Fig. 1) to operate to reverse the direction of current now in the loop for metering and supervisory purposes. When the called party releases D falls back, and when the calling party clears A, B, JK, TR and TK release. G pulls up, re-energizing B to guard the switch and G and DM interact stepping PLS. When a free register-controller has been found G releases and B falls back. If all the register controllers are busy contact 25 of the bank wiped bv 295 will. not be carthed, and the switch will. stop on that terminal. If TRG should be picked up with PLS in this position, A, B, TK and TR would operate and Busy Tone from lead BE would be returned to the calling subscriber over wiper 294. Compulsory release. A periodic time pulse is connected to lead PL, and this pulse with relays TZ and TR controls the release, of the registercontroller in the event of premature release, or delayed dialling. If the revertive-control switches are held during setting in a local control circuit. the connections shown dotted in Figs. 1 and 4 and an additional relay JG must be provided to guard TRG- until the switches at the distant exchange have been reset. Specification 526,248 is referred to.