Patent GB-693014-A (GB)
Title: Electronic translator for automatic telephone systems
IPC: H04Q3/00
Filed: 1950-10-25
Abstract: 693,014. Automatic exchange systems. AUTOMATIC ELECTRIC LABORATORIES, Inc. Oct. 25, 1950 [Oct. 26, 1949], No. 26028/50. Class 40 (iv). In a translator common to a group of register-controllers, the translations corresponding to the various office codes are recorded magnetically on a rotating drum and are generated in succession during one revolution thereof. When the translator is seized by a registercontroller, the office code is transferred to registers therein and a coincidence detector which receives impulses on a 3-digit counter as the drum rotates from its zero position causes the opening of an electronic gate at the proper time to allow the required translation to pass to the registercontroller. Different translations are provided according to the class of calling party, and, where the system provides for alternative routing, an alternative translation is available when the direct route is busy. General arrangement. The drum 1311 is capable of bearing 10,000 longitudinal rows of magnetized spots which pass under spaced pick-up heads as the drum rotates. Ten rows are allotted to each 3-digit office code to supply 3 translations corresponding to the various classes of the calling party and a fourth translation if alternative routing is provided. The translations are recorded in 4-unit code form and comprise routing digits, one or more rate digits and certain control signals. Each row includes an indexing spot which in passing under a pick-up head 1313A delivers a pulse, amplified at 1360, over wire C1338 to an electronic counter 1370, and the latter in turn controls similar units, tens and hundreds counters U1220, T1130, H1120, which thus indicate by their setting the translation being generated at any particular time. A single reset spot which passes under a pick-up head 1312A in the zero position of the drum serves to zeroize the counters. The translator is intended for use in the system described in Specification 692,999, the register-controller, Figs. 5-10, 15-18 (not shown), being similar to that disclosed therein. Certain offices are denoted by two code digits only, and the first numerical digit is then used to make up a 3-digit code. When the motor driving the drum 1311 starts, contacts 1340 close. When the reset spot is picked up in the zero position of the drum, tube 1351 is cut off and tube 1350 fires, so that relay R1335 operates to ground wire C1337 to make the translator available for use. Also, a positive pulse is applied to wire C1339 to zeroize the counters 1370, U1220, T1130 and H1120, each of which comprises ten pairs of trigger tubes. Operation. The translator is seized by the operation of relays R1220, R1230 after three digits have been received in the registercontroller, and these digits are recorded on relay registers H, T, U. In addition, one of the class relays R1345, R1350, R1355 is operated in series with R1340. R1210 then energizes and applies positive grid bias to tube 1202A in a pick-up pulse circuit 1201, the purpose of which is to prevent transmission of an incomplete translation. At each 10th pulse received by the counter 1370, tube 1202A is fired by a positive pulse on its screen grid and cuts off tube 1201A. The tubes of the gates 1250, 1260 have their grids connected over C1280 to positive potential which, however, is reduced to an ineffective value as long as tube 1201A or any tube VH, VT, VU of the coincidence detector is conductive. As the units counter U1220 advances, wires C1250-C1259 are marked in succession with high + potential and C1260-C1269 with low + potential. As long as no digit is recorded in the units register relays U, the first set of wires are effective and tubes VU fire in succession. When one of the relays is operated, however, it prevents the firing of the corresponding tube by switching over the connection to a wire of the other set. In the same way the counters T1130 and H1120 operate in conjunction with the tens and hundreds registers to control tubes VT, VH. Thus, when the setting of all three counters agrees with the registered office code no tube will be conductive in the three groups, and therefore at a zero count of 1370 when tube 1201A is cut off the full positive potential on C1280 becomes effective to bias the gates 1250, 1260. The principal route gate 1250 is normally enabled by a gate control circuit 1290, while the alternative route gate 1260 is blocked, and the positively magnetized spots on the drum 1311 generate pulses which by driving the grids of the corresponding tubes more positive cause them to fire and pass on the pulses. The outputs of the gates are connected in multiple to code register tubes 1101-0 to 1101-9 which are made effective in succession by the connection of + bias to their screen grids over wires C1150-C1159 by the counter 1370. The first register 1101-0 serves only to deal with alternative routing as explained below. The remaining registers control relays such as W11-Z11 which transfer the translated digits to the registercontroller. These may comprise up to 6 routing digits, a tariff digit and two control signals, the first to tell the register-controller how many of the digits stored therein are to be transmitted in addition to the routing digits and the second to start identification on calls to be ticketed or to indicate the tens digit of the tariff if required. The release of the translator is initiated by a relay operated when the first routing digit is transferred, or it may be controlled positively by the final signal emitted by the translator. Alternative routing. It is assumed that there are 9 outgoing direct routes for which alternative routes are provided, and the translator includes a corresponding set of all-trunks-busy relays ATB1-ATB9. The first translated digit, which goes to the register 1101-0, denotes the route, the digit being 0 if there is no alternative route. If, for example, the digit is 1, - potential is connected to wires C1195 by the operative tubes TAW, TAX, and if ATB1 is up this is extended to the grids and screen grids of tubes GT1291, 1292 in the gate control circuit 1290. These tubes therefore fire, cutting off the principal route gate 1250 (controlled from the cathode of GT1291) and enabling the alternative route gate 1260 (controlled from the anode of GT1292). Magnetizing the drum in accordance with translations required. For this purpose, there are provided a number of spaced magnetizing heads which are in practice wound on the same cores as the pick-up heads. The magnetizing heads comprise two windings, the lower when energized producing a negative spot (which produces no effect in the pick-up amplifier) and the upper winding, which has twice as many turns, producing a positive spot. Ten translation keysets 1413-1422 are arranged to mark four wires C1466 leading to a magnetizing circuit which controls the magnetizing heads, these being connected up alternatively by relays R1360, R1365, R1370, R1375 controlled by corresponding keys. Each key-set includes a skip key and interlock springs such as 1413S which are closed when any key is actuated. Three office code key-sets 1410-1412 are provided for controlling the hundreds, tens and units relay registers of the coincidence detector. A manual start key K1255 controls relay R1250 which connects up busy relay R1220. R1240 operates provided no register-controller is calling for a translator and connects ground by way of the interlock keys to C1245 to register the office code digits, whereupon R1210 pulls up, followed by key-connect relay R1460. The magnetizing circuit comprises pairs of tubes such as 1451A, 1451B which are normally blocked until + potential appears on their screen grids from C1280 when coincidence occurs, even though the cathodes are periodically driven more negative by pulses from C1338. When there is coincidence, however, these pulses fire the tubes such as 1451A and produce negatively magnetized spots on the drum. The grids of the tubes such as 1451B are normally biased negatively but are connected by way of the translation key-sets to wires C1150-C1159 to which high + potential is applied in succession by the counter 1370. Thus the tubes corresponding to each operated key are caused to fire to produce positively magnetized spots. All the tubes are cut off when coincidence ceases. R1460 initiates the slow release of R 1250, which brings about release after one revolution of the drum. Specification 657,058 also is referred to.