Patent GB-528971-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04M15/04
Filed: 1939-05-05
Abstract: 528,971. Automatic exchange systems ; metering systems. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., TAYLOR, R., and BAKER, G. T. May 5, 1939, No. 13538. [Class 40 (iv] In a telephone system comprising a number of zones, each with its own linked numbering scheme, calls originating in a zone are routed under the control of apparatus at an exchange of the zone in which also the apparatus for recording particulars of the call is situated. In some cases a register-translator at the criginating office routes the call to a second registertranslator at the routing and recording office. In the national dialling scheme suggested, the prefix digits dialled to select a zone depend on the calling as well as the called zone so that the number of digits needed for a call between two zones is smaller the greater the community of interest between the zones. Calls between non-register-translator systems, Figs. 1 and 2 and Fig. 3 (not shown). Internetwork calls are characterized by a first digit 8. If the call originates at a satellite such as A, the original junction 10 to the main exchange is released and a high grade junction 11, which is also used for zero calls, is seized. In this case, a distinctive signal causes the incoming end to be switched from the operator's circuits to equipment TLRS unless the calling party is at a coin box in which case the call is switched to a characteristic jack CB. The equipment TLRS is now associated by HS with an idle route-discriminator RD which translates the next digits received into a routing number the first digit of which sets the switch OGS associated with TLRS. The numerical part of the number may be stored and re-transmitted by a mechanical regenerator of the kind described in Specification 458,095. At some stage before the connection is released, the outgoing relay set ORS is associated with identifying equipment which operates as described in Specification 525,902 and the calling number is sent forward. The dialled digits are already stored in TLRS and at a suitable stage HS associates TLRS with call-recording apparatus operating as described in Specification 516,409. The same junction may be used for inter-network calls as for internal calls in which case a discriminating arrangement of the kind described in Specifications 473,003 and 473,015 may be used. In an arrangement in which there is no spare first digit, Fig. 3 (not shown), 01 ...09 can be used to characterize inter-network calls. 00 or 0 followed by a pause routes the call to an operator. An attempt by a coin-box to set up an inter-area call is routed to the operator over a characteristic jack. In the case of more complex-areas a call from an outlying exchange may employ a register-translator to route the call to the register-translator and call recording apparatus. Calls between register-translator network and outlying district E, Figs. 4, 5. A spare code is allotted for this service and causes a local register-translator LRT to route.the call to the tandem exchange B. The whole untranslated number is then transmitted bv LRT to the register-translator TRT at B to cause the completion of the connection. The number is stored in TLRS for transfer to the. ticketing apparatus in known way. Calls from certain originating exchanges to E may be established without using a translator at B. In a modified arrangement, special 0-level register-translators are used at the originating exchange for ticketed calls. These may be of simple type, as shown in Figs. 8 and 9, since they only need to provide for two translators, one for routing to an operator and the other for routing to the nearest parent exchange (shown shaded) at which the ticketing apparatus for the exchanges based on it is situated. Coin-box calls are extended in the arrangement of Fig. 6 over special first selectors to enable them to be distinguished at the main exchange. In the case of 00 calls the operator can cause the display of the calling number. Outgoing calls needing to be ticketed are established as in the other arrangement. Incoming calls are established with the help of a register-translator in a central or sub-central exchange. A discriminating device at the originating exchange indicates whether ticketing apparatus is to be taken into use. Simplified zero level register-translator, Figs. 8 and 9. When the register-translator is seized by the A-digit switch, which may be of the kind described in Specification 469,184, impulse relay A and relays B, BB and P are operated. The B- digit is repeated to magnet RM of a mechanical regenerator of which the marking magnet MM is energized by dialling relay C and to magnet FM of a switch F. At the end of the digit, the relapse of C releases MM to displace the selected pin and ON pulls up and locks. If the call is for a manual board, the B-digit is 0 and a circuit is made over F4 for SM which energizes SC. For any other digit, a circuit is made only for SC, which arranges for the operation of start-relay IG when next the magnet springs IMP2 open so that subsequent impulses are delivered to the magnet FM until the arrival of wiper F8 on terminal 40 energizes the stop relay SZ. The loop springs 1MP1 are shunted over wiper F2 in the first 11 positions of F2 and again in other positions of F2 and F6, the terminals of which are multiplied so as to divide the total number of steps into impulsing and inter-digital pause periods. As shown, the routing number is 3148. When a free registertranslator in the exchange ahead has been seized, relay D pulls up and energizes SS which energizes the sending magnet TM of the regenerator and the whole number recorded is sent out by its springs IMP3 as described in Specification 458,095. When the number has been completely received at the register-translator ahead, O is released and CO releases the register-translator and A-digit switch. In cases where the B-digit is 0 a different translation is sent in accordance with the connection of banks F1 and F5 owing to the operation of SM. The stop relay SZ is energized on terminal 39 of F8 and energizes relay CO to release the translator as soon as the routing number has been sent. On the relapse of BB, IS is energized and the regenerator runs down. The restoration of FM takes place when ON falls on the return to normal of the regenerator. The zero routing is also sent if no B-digit is dialled and a thermal relay TH accordingly has time to operate. If, in a dialled call, the subscriber is unduly long in dialling any digit, S and Z relays TP and M cause the operation of SS and the switches ahead and the register-translator are released. Ground connected temporarily to wire FR releases the A-digit switch and causes NU tone to be sent back. The register-translator may send more than one translation, e.g. as described in Specification 469,184. Outgoing junction circuit at originating exchange, Fig. 10. Relay JA, which operates over the third wire when the junction is seized, extends the talking circuit back to the impulsing loop and energizes JB. If all calls over this junction are to be recorded, JB energizes RA. If some calls only are to be recorded, the link 17/18 is provided and RA is only operated if a special signal over the private wire has already operated IP. Marking magnet IMM of an impulse regenerator is operated and the circuit is associated with calling-subscriber identirying equipment. The third wire of every line carries a code which is characteristic of the line and consists of two A.C. marking impulses in characteristic ones of five possible positions per digit. The invariable part of the identification code reaches the p lead via a non-linear resistance NLR. If the identifying equipment is not in operation when RA pulls up, earth on wire S energizes RB which locks up, starts the common equipment and connects receiving magnet IRM of the regenerator to lead PU. During the identification, five impulses per digit are sent over PU to the receiving magnet and the A.C. marking impulses operate IP which disconnects the marking magnet IMM to cause the displacement of a pin and the energization of MMR. The latter locks until the end of the pulse and disconnects IP which on falling re-operates IMM. When the identification is complete, RA is released. The transmission of the calling number to the ticketing exchange is described below. Trunk line relay set at routing and recording exchange. Timing and recording call. Relay R, Figs. 11, 12, is operated over the impulsing loop and is followed by IB, BA, KR, MD. The driving magnet HSM is driven in a self-interrupting circuit until an idle registertranslator is reached whereupon K pulls up to stop the switch and energizes KA which releases KR and energizes KB, IBB. A signal is given by the reversal of current in the line to start the transmission of the number to the registertranslator. The holding winding of K is in the opposite direction to its energizing winding to prevent double connections. The registertranslator then operates in known manner to extend the connection and also sends the wanted number in 5-unit code form to the regenerator magnets 2RM, 2MM. On the completion of the sending operation, K, KA and KB fall back, the talking circuit is completed and HS goes home. Relay ID responds to the reply signal, releases MD and energizes DD which repeats the reply signal to the originating exchange. After a short interval, MD falls and D pulls up over HS10 and connects six-second pulses to HSM. After two steps, which give a six to twelve second interval to ensure that wrong numbers are not ticketed; PU is operated and connects the six-second pulse lead to magnet USM of the minutes timing switch. PU is then released until HS reaches position 13 at the beginning of the second minute, whereupon it gives USM another pulse. This operation goes on, if the conversation continues, until HS reaches its last terminals, whereupon DP operates and locks and changes the circuits of PU