Patent GB-376754-A (GB)
Title: Improvements in or relating to electrical signalling systems
IPC: H04L12/18
Filed: 1931-04-13
Abstract: 376,754. Electrical signalling systems. ASSOCIATED TELEPHONE & TELEGRAPH CO., 1033, West Van Buren Street, Chicago, U.S.A. April 13, 1931, No. 10887. Convention date, April 19, 1930. [Class 40 (i).] Relates to systems for transmitting information regarding the selling price of stocks. The system is similar to that described in Specification 368,369 wherein the various stocks are coded by the operation of various combinations of letter keys which control a plurality of registers, the registration being translated into a numerical basis to operate further registers. Price and range quotations appropriate to the stock are registered in further registers and signals are then transmitted under the control of all the registers to effect at a plurality of receivers the selection and operation of the appropriate stock indicators. The invention comprises inter alia the following modifications of the system described in the prior Specification. (1) The translating means for translating the stock letter code into a three-digit numerical code are modified to include two cross-connecting frames and relays individual to the coded stock. (2) The impulse transmission to the receiver is effected under the control of step-by-step counting switches which facilitate the simultaneous transmission of characteristic impulse codes to the receiver over two line wires. The various digits are transmitted as interspersed groups of positive and negative impulses. (3) Modified receiving arrangements involving common counting relay chains for operating stock and price digit registers which are adapted to control the operation of a local impulse sender for setting simultaneously a plurality of price indicators appropriate to the stock. Stock letter and price-digit registration. As described in the prior Specification, the stocks are coded by one, two, or three letters, operation of the corresponding keys causing successive energization of the appropriate relays in the registers SR1, SR2, SR3. The price digits are registered successively on the price registers PH .. PF, Fig. 7, upon operation of the price keys DK, Fig. 5, the various keys closing different combinations of circuits to operate corresponding register relays. Stock range registration. The type of quotation, e.g. highest, lowest, &c, price, is signalled by operation of the appropriate key RK and registered in register SR, Fig. 6. Stock code translation. Upon operation of the transfer relay 701 of the price " hundreds " register after registration of the hundreds digit, circuit is closed over lead 601 and contacts of operated relays on registers SR2, SR3 for a relay, e.g. BBA individual to the stock which relay extends the leads connected to contacts of register SR1 through a cross-connecting frame 1DF1 and a second frame 1DF2 to appropriate contacts with the numerical groups CD1, CD2, CD3 thus effecting a translation in code. The translated code is then registered in the stock registers SH, ST, SU by the operation of a relay in each register. Initiation of signal transmission to receivers. Upon operation of the relay 610 after registration of the stock " range," relays 435, 436, 710, 711 are operated to switch the registers through to the impulse sending equipment shown in Figs. 8 and 9 and " start " relay 612 is operated over contacts of operated register relays 406, 407, 408 to initiate the operation of the sender. Release of stock relay and registers. When relay 612 is energized relay BBA and a relay 207 which is operated in parallel with BBA are released. When operated relay 207 directly earths the locking conductor of the registers SR1 SR2, SR3 and energizes 208 but when released, upper winding of relay 208 is connected in the locking circuit and owing to its high resistance effects release of the registers. Relay 208 also then releases and restores normal conditions. Transfer to register RS2. As described in the prior Specification, the register RS2 is placed under control of the operator to facilitate registration of a quotation while the first quotation is being transmitted to the receivers. Operation of impulse sender. When relay 612 operates, conductor 617 is earthed to energize relay 801 and thereby render interrupters 823, 824 effective for driving the counting switches CS1, CS2. Interrupters 825, 826 driven on the same shaft as interrupters 823, 824 are adapted to transmit impulses simultaneously over leads 851, 852 as determined by the counting switch CS1 while impulses are transmitted over leads 853, 854 alternately with those over leads 851, 852 by interrupters 827, 828 in accordance with the operation of the counting switch CS2. The alternate transmission of the impulses over the pairs of leads enables the settings of the respective registers to be transmitted by interspersed positive and negative impulses transmitted over a pair of line wires. Each counting switch has two sets of wipers each set being allotted to two registers, e.g. the first half of the bank contacts of the set of wipers 813, 814, 815 being connected to the register SH and the second half to register PH. Similarly wipers 816, 817, 818; 901, 902, 903; 904, 905, 906 are respectively associated with registers ST, PT; SU, PU; SR, PF. The interrupters 823, 824 alternately control the stepping magnets 809, 910 of switches CS1, CS2, the wipers of which are stepped to search for the marked combinations of leads from the registers ST .. SR. During stepping impulses are transmitted over the leads 851 .. 854, the number over each line characteristic of the respective register being determined when the appropriate group of wipers reaches the marked combination to effect the operation of " stop " relays 808, 812, 909, 913 which open the circuits of the interrupters. When all the " stop " relays are operated relay 805 is energized to open the locking circuits of the " stop " relays and to complete self-interrupting circuits for the stepping magnets which drive the switches to a subnormal position preparatory to sending out impulses characteristic of the registers PH.. PF. Relay 805 is subsequently released by slowrelease relay 804 and stepping is resumed, transmission of the price digits being effected in a manner similar to that previously described under the control of the second half of the contact banks. After transmission of the second set of digits, operation of relay 805 causes relay 942 to release the stock and price registers, and restore the sending apparatus ready for operation by the register set RS2. General arrangement of system, Fig. 10. As described in the prior Specification, the stocks are dealt with by two operators each having a transmitter T1, T3 and a spare transmitter T2, T4 which may be brought into operation by keys TK1, TK2. Each operator controls series connected receivers RE1 .. RE5 ; RE2 .. RE6 arranged in pairs so as to facilitate indication at a single position of the complete list of stocks. Repeating arrangements, Fig. 10. The impulses transmitted over leads 851 .. 854 operate relays 1001 .. 1004 which effect the transmission of positive and negative impulses over line wires 1005, 1006. The relays 1001, 1002 send positive impulses simultaneously over the line wires and relays 1003, 1004 transmit negative impulses interspersed with the positive impulses due to the alternate operation of the interrupters 825 .. 828. Receiving arrangements. Each line wire is provided with two oppositely polarized relays 1401 .. 1404 which effect the separation of the impulse trains individual to the various registers. Accordingly the impulse relays 1401 .. 1404 repeat the respective impulse trains in appropriate relay counting chains SH .. PH; .. SR .. PF, Fig. 11, over leads 1421 .. 1424. The repeated impulses over each lead are recorded in the counting chains each of which comprises a plurality of relays which are operated successively in pairs. When all the impulses are received, various combinations of circuits characteristic of the impulse trains are closed in the groups 1131 .. 1134 over the lower contacts of operated relays in the counting chains to operate the appropriate relay combinations in the stock groups of registers SH .. SR, Fig. 12. Each counting chain is so arranged that after receipt of the fifth impulse the operated relays are released ready for operation by subsequent impulses. Upon operation of the appropriate relays in the stock registers the relays are maintained locked over lead 1213 which includes relays 1415. This relay operates to de-energize relays 1201, 1202 and operate relays 1201<1>, 1202<1> to effect a transfer of the marking leads 1131 .. 1134 from the stock group of registers to the price digit registers PH .. PF. The price digits are registered in a manner similar to that described in association with the stock registers. Selecting indicators appropriate to stock. When lead 1434 is earthed by operation of relay 1415, circuits are closed over the pyramidal contacts of the stock registers, that of the register SH effecting the selection of a relay such as 1301, and those of the registers ST, SU effecting selection of a relay such as 1641 individual to the stock. Similarly in accordance with the stock range a relay in the group 1655 .. 1659 is operated to associate the appropriate set of indicators in the stock group with the leads 1428 .. 1431 of a local impulse sender, Fig. 15, which effects the restoration and setting of the price indicators. Restoration and operation of price indicators. Each indicator comprises a numeral drum driven by a ratchet mechanism and having a cam adapted when the drum is in the " blank " position to connect the operating magnet to the lead 1632, but when the drum is in any other position allows connection with earth. A local sender LS, Fig. 15, comprising a counting chain of relays operated by interrupter 1459, Fig. 14, is adapted to control the transmission of impulses for eff