GB516348A - Improvements in or relating to automatic or semi-automatic telephone systems - Google Patents

Abstract

516,348. Automatic exchange systems. POLLAK, J. E. (Associated Telephone & Telegraph Co.). June 14, 1938, Nos. 17730/38, 34908/38 and 308/39. [Class 40 (iv)] In a large network which is divided into zones each comprising a number of exchanges grouped around a central exchange, each zone having its own numbering scheme comprising one or more exchange digits and numerical digits and each zone being designated by a 2-digit number, toll or inter-zone calls are made by dialling 0 followed by the zone designation and the numerical digits, and the register-translator at the originating exchange routes the call to a junction outgoing from the central exchange in the appropriate direction and transfers the complete wanted number to a toll control circuit individual to that junction. Different grades of junctions'are provided between the central exchanges and within the zones, and the grade to be used is determined by the register-controller. In general, calls within a zone are metered on the subscribers' meters, while toll calls are recorded by automatic ticketing equipment at the central exchange, and therefore the register-translator determines the nature of the metering, and, when ticketing is necessary, assesses the tariff and transmits to the toll control circuit a digit indicative thereof, together with the calling number. The further extension of the call is controlled by a register-translator or converter associated with the toll control circuit, the zone digits being translated into a routing number, and the ticketing equipment becomes associated with the toll control circuit at the end of the conversation to effect printing of the information recorded therein. The transfer of the recorded digits to the central exchange is effected by code impulsing, and A.C. impulsing is employed in extending the connection therefrom. The invention relates to arrangements whereby the register-controller at the calling exchange, in addition to its route-determining functions, also transmits the calling, party's identity to another stage of the connection at which particulars of the connection are collected for automatic ticketing, a register-translator or convertor being taken into use at this stage to receive the necessary particulars for completing the connection. The circuits described, together with those described in Specifications 516,408 and 516,409 relate to the same system, further features of which are also claimed in Specifications 516,413, 516,414, 516,415; and 516,416. Identical figures in these Specifications have the same numbers. The invention is described with reference to the Belgian telephone system. Fig. 2 shows the trunking layout at the Hautrage and Mons exchanges, the latter being the central exchange of the zone, Hautrage having a capacity of 600 lines with numbers beginning with 57 and Mons having a capacity of 8,000 lines with numbers beginning with 2. Double-wiper bidirectional call finders 1LF, 2LF are employed, and a group of register-translators RT is provided for each 2,000 line group. The calling number is therefore determined by the identity and setting of the call finder. The group selectors 1GS, 2GS at Hautrage have access to local final selectors, to junctions to nearby exchanges, and to good and poor grade junctions to Mons. The incoming selectors IS at Mons have access to local selectors LGS, to selectors LS giving. access to other exchanges within the zone and to special service selectors TS. These last give access to operators' positions OP, to speaking clocks &c. and over rotary switches TLF1, 2 to good and poor grade inter-zone junctions. The overflow positions of TLF1, 2 are wired to operators' positions. Each inter-zone junction includes a toll control circuit TLCC which takes into use a converter C for setting up the connection, and, at the end of the call, a printercontroller PC. The latter, which has access to a date and time unit DTU, controls the operation of associated printing units PT, PU, one of which prints a ticket and the other a record on a continuous strip. Various types of calls originating at Hautrage are described. Seizure of register-translator and registration of calling number, Figs. 5, 6. The call finders, Figs. 3, 4 (not shown), are of the kind described in Specification 376,265. Relay 112 starts the switch RTF, and test relay 111 energizes when an idle register-translator is found. Relays 115, 116, 114 pull up, the last being sluggish, and ground on wire 138 operates 187, Fig. 15, followed by 189, 190, 191, and busy ground is returned over wire 141 to wire 110. The 200 line group is indicated by the extension of ground or booster battery from one or more wires 123-125 over wires 139, 140, 142 to relays 198-200, Fig. 16. In the case of booster battery, 201 (associated with a rectifier 363) operates in series with one or more of 198-200, and the latter lock in series with 197. Relay 114 completes the out-impulsing circuits from relays 209, 210, Fig. 13, over wires 139, 140 and 108, 109, connects wire 142 to relay 117 and makes the stepping circuits for the finder in parallel with relay 196, Fig. 18, over wire 136. The tens and units digits of the calling number are thus recorded on the switches RS3, RS4; change-over being effected by 194, and 193 finally pulls up. When the finder switches through, relays 187, 188, Fig. 15, are connected over wires 137, 138 and 106, 107 to the calling loop. Relay 112 falls back, and, if the hundreds digit of the calling number is odd, connects ground from wire 101 over wire 136 to operate 202, Fig. 16. The switch RTF is common to a pair of call finders, and relays 112, 115-117 are duplicated. When the register-translator has completed its operations, 117 energizes over wire 142, switches through the talking circuit, disconnects 115, 116, 114 to release the register-translator and remains locked over wire 110. Register-translator, Figs. 7-16, arranged as shown in Fig. 17. Two bidirectional switches TD1, TD2 and three rotary switches RS1, RS2, RS5 are provided for registering the dialled number, the last switch acting as the in-sequence switch. The variable part of the calling number is registered on the relay group RG4 (198-202) and switches RS3, RS4. On toll calls, the switch TD1 drops back in response to the first digit 0, and the switch TD3 is set under the combined control of TD1; TD2 to determine the routing . digits and the tariff. The setting of TB1 also chooses a wiper of the out-sequence switch RS6, and controls its advance to a. subnormal position when necessary. Impulse transmission is effected by the relay group RG7 under the control of counting relays RG5, and a further relay group RG6 comes into operation for coded transmission. The relay group RG8 takes ,care of irregular operations. The outsequence switch RS6 by means of cross-connections to its banks, Figs. 22-26 (not shown), controls the transmission of the digits which are necessary for setting up the various types of calls and for controlling metering or ticketing. Local calls. Relays 187, 188 energize over the calling loop and dialling tone is sent. The first two digits are repeated.to TD1. the next two to TD2 and the final digit to RS1, the switch RS5 being advanced after each digit by means of dialling relays 204, 203. At the end of the second dialled digit, the release of series relay 239 connects up 235, which extends pulse wire 399 first tb 213 and then to 211, and impulses are sent over the out-impulsing circuit 139, 140 and to the counting relays RG5, 209, 210 being shunted out by 212 during each train. The counting relays 216-221 operate in turn until six impulses have been counted, when 221 holds and 216-219 re-operate for succeeding impulses. Each train is terminated when 214 operates over contacts of the counting relays and a marked wire of the group 1-0, and the inter-digital pause is brought about by the successive relapse of 212, 215, 214. Each operation of 214 advances RS6 one step. The digits to be sent are determined by the connections to wires 1-0 made in successive positions of RS6, wiper 296 of which is chosen over wiper 261 of TD1. Digits which are the same for a particular kind of call whatever the final exchange are marked directly by RS6, whereas digits which are variable for different exchanges are marked via wipers of the register switches. The first digit 2 indicates that the call is to be metered in the ordinary way. No routing digits are required on a local call and therefore the remaining digits consist of the last three dialled digits set on TD2, RS1. Finally ground is extended over wire 317 to wire 142 to bring about release of the register-translator. The relapse of 187, 188, 189 brings about the restoration of the various switches to normal or subnormal positions. Calls terminating in the central exchange. These also are controlled over wiper 296 of RS6, but in this case a circuit is made over 264 of TD1 for advancing RS6 to position 16 before 235 pulls. up to start impulse transmission. The metering digit 2 is followed by a single routing digit which selects a poor grade junction, and the last four dialled digits are sent to set the selectors at the central exchange. Calls through the central exchange to other exchanges in the same zone. For small exchanges of 1,000 lines or less, wiper 297 is used. in co-operation with the second part of its bank. After the metering digit 2, three routing digits are sent, the first two being invariable and the last dependent on wiper 265 of TD1, followed. by the last three dialled digits. For larger exchanges, wiper 299 is used in co-operation with the second part of its bank, and the last four dialled digits are sent. Direct calls. to nearby exchanges. Wiper 298 of RS6 is used in co-operation with the second part of its bank, and the metering digit 2 is followed by a single routing digit and the numerical digits. If, however, the wanted exchange is