Patent GB-473003-A (GB)
Title: Improvements in telephone systems
IPC: H04Q3/58
Filed: 1936-04-03
Abstract: 473,003. Automatic exchange systems. AUTOMATIC ELECTRIC CO., Ltd., TAYLOR, R., and BAKER, G. T. April 3, 1936, No. 9973. [Class 40 (iv)] In a satellite exchange, discrimination as to destination of call and determination of the charge are effected separately and in accordance with the same or different numbers of digits in common apparatus associated with a selector when a call is made. The common apparatus, includes a mechanical impulse repeater or " regenerator " as described in Specification 458,095 which stores and retransmits the impulses dialled. In the case of a main-exchange call, the selector is automatically stepped to its first level by the common apparatus to select an idle junction and the complete number dialled is then repeated to the main exchange. The common apparatus can also effect absorption of a variable number of digits and prevent the establishment by coin-box subscribers of certain single-fee and all multi-fee calls. The selector, Figs. 1-3, is designed for optional use either at a satellite exchange with the common discriminating means as shown or as a first code selector with a register - controller of the code-translating type as described in Specification 469,184. Certain features of the system described form the subject-matter of a divided Specification 473,015. Discrimination ; digit absorption. The seizure of an idle discriminator takes place similarly to that of a register-controller as described in Specification 469,184. Relay 1A operating over wiper PU connects relay 1B in series with the receiving magnet MR of the regenerator, and relays 1B, LR operate. On the receipt of impulses repeated to 1A by relay L, relay 1B is shortcircuited and magnet MR operated to set the regenerator receiving ratchet-wheel X. The impulses are also repeated to magnet DM of switch D1 .. D7 and if the first digit, e.g. 8, represents a mainexchange connection, a circuit is completed over wiper D7 and terminals m, k, a, for relay JD which operates LD releasing LR. During the relapse of LR an impulse is transmitted at contacts jd4 to relay A causing the selector to move to its first level to select a junction to the main exchange. The relapse of LR also completes a circuit over off-normal contacts MN1 and discs Z, Y of the regenerator for relay P which releases IP operated by relay JD and regenerator off-normal relay ON. The time of release of IP is sufficient to provide hunting time for the selector and the regenerator sending magnet MS then operates to send out the first digit. The other digits are similarly sent out, relay IP providing the necessary inter-digital pauses. For a local call (first digits 715.. 718), relays IDA, IDB are energized over terminals j, m, after the first two digits and relay LD over terminal g after the third. The release of LR by LD initiates the operation of the regenerator as before but the first two digits are absorbed due to the non-operation of relay JD and no inter-digital pause is inserted since no circuit is completed for relay IP. After the second digit, IP is able to operate over wiper CN3 of a control switch advanced one step per digit by relay P, and relay JD is then operated over its left-hand winding so that the remaining digits are sent out effectively by springs IMP. Discrimination can take place optionally after the first, second or third digit by making connections from bank D7 to terminals j .. m to operate or not relays IDA, IDB as required and by connections to terminals b .. h to extend the connection to relay JD or relay LD at theappropriate time. Relays CA, CB, CC operated over banks D2 .. D6 provide for operation of the cutoff relay CO after any desired number of digits. Metering. This may be determined by any number of digits up to five by the banks D2 .. D6. If, for example, it is dependent on two digits, the contact engaged by D3 for the first digit is connected to relay SA and the contact engaged by D2 (connected up by SA) after the second digit is connected to one of the leads 1 .. 4, Fig. 8, causing the operation of either, both, or neither of relays IMA, IMB. Similarly, for determination by five digits, relays SA ... SD will be energized in succession over banks D3, D2, D4 D5, and the relevant contact in D6 will be connected to leads 1 .. 4. The condition of relays IMA, 1MB is repeated to corresponding relays MA, MB in the selector over leads FR, MB to connect up the appropriate metering lead for single, double, triple, or quadruple operation. Relays IMA, IMB also complete a circuit for relay ZM which restores the switch D1 .. D7 to normal. Preventing calls by coin-box subscribers. For ordinary subscribers, relay RS, Fig. 9, is operated in parallel with resistance YA, Fig. 2, but for coin-box subscribers ground on lead D short-circuits this relay so that for certain single-fee connections determined at bank D3 and for all multi-fee connections, relay IM will be operated to disconnect the outgoing loop and to operate the forcedrelease relay M in the selector. Specifications 391,151 and 435,411 also are referred to in the Complete and Provisional Specifications respectively.