Patent GB-849497-A (GB)
Title: Improvements relating to digital translating apparatus as employed in automatic telephone systems
Inventor: WARMAN BLOOMFIELD JAMES
IPC: H01H67/22
Filed: 1956-10-03
Abstract: 849,497. Automatic exchange systems; cross-connecting fields. SIEMENS EDISON SWAN Ltd. Oct. 3, 1957 [Oct. 3, 1956], No. 30136/56. Class 40 (4). In a translator a combined translating, crossconnecting, and component - mounting field consists of a number of mounting plates, each in the form of a sheet of insulating material, which in use are clamped together to form a pack, each mounting plate having thereon busbars and terminals between which gate circuit components or isolating components or crossconnecting jumper wires appertaining to only one digit place of the multi-digit inputs and outputs catered for by the translator may be connected, the arrangement being such that, when the plates are clamped up to form a pack, the terminals on each plate, which extend through the plate, make contact with those of the adjacent plates to form the components carried by the plates into gate and other circuits for performing the required translations. Outline of construction and operation of the translator.-Fig. 1 shows in simplified form a translator for translating a two-digit exchange code into three routing digits, the plates P1, P2 and P3 appertaining to the routing digits, and P4 and P5 to the two digits of the code, respectively. The through-connecting terminals DT at the top and bottom of each plate, of which only twelve are shown, provide input and output paths for the incoming and outgoing digits when the pack is clamped together. Busbars BB, of which only those corresponding to digit values 1 to 6 are shown, are provided on each plate, as are also through-connecting terminals CPT at the sides of each plate, the latter serving as gate circuit and translation common points. The contacts A, B, C, D and E are connected to typical ones of five sets of ten terminals corresponding to the ten possible values of the first and second code digits, and of the first, second and third routing digits, respectively, the terminals so connected being assumed to correspond to digits " 5," " 4," " 3," " 6 " and " 2," respectively. Consequently, on sheet P4 the terminal corresponding to A is wired to bus-bar No. 5, on P5 that corresponding to B is wired to No. 4, on P1 that corresponding to C is wired to No. 3, on P2 that corresponding to D is wired to No. 6, and on P3 that corresponding to E is wired to No. 2. One of the terminals CPT is allocated to each exchange code and the components necessary for translating a code into a routing number are connected between the relevant bus-bars and the point CPT corresponding to that code, these components being a resistor R1 in respect of one of the code digits and rectifiers MR1 to MR4 in respect of the other digits. To obtain a translation the two code contacts, A, B, corresponding to the relevant code, in this case " 54," are operated and all thirty of the output coupling contacts, such as C, D, E, are closed. Negative battery potential is thus applied to R1 and MR4 and hence to the common point CPT. The output terminals T are normally maintained at a potential less negative than that of negative battery. Consequently MR1, MR2 and MR3 now conduct and the terminals T connected to contacts C, D, and E go more negative than normal to indicate that the wanted translation is " 362." Details of construction.-Each mounting plate 8 (Fig. 2) is of thermosetting plastic sheet # inch thick, 17¢ inches high and 12“ inches wide, and is provided with twelve bus-bars 13 (of which only four are shown). Thirty-two terminal mounting blocks, each fixed to the plate by two self-tapping screws 10, are arranged as shown, each row of four terminal mounting blocks accommodating thirty-one throughconnecting terminals as indicated by the vertical lines 11. Adjacent each terminal location is a hole 9 in the plate to permit a contact-making part of the terminal to protrude through the plate to connect with the corresponding terminal on the adjacent plate. The bus-bars 13 consist of lengths of stout copper wire (0.044 inch diameter) each supported by five pedestal terminal supports 12, riveted through the plate 8. Each through-connecting terminal 18 (Figs. 2A, 2C) consists of a member stamped out from a nickel-silver sheet of about 0.025 inch thickness and formed and mounted so as to embrace the relevant terminal mounting block 7 (or the pair of such blocks in the case of a terminal located at the junction of two blocks), a first limb (the upper in Fig. 2C) being located in a recess 7A in the front face thereof, and the second limb in a recess 7B in the rear face thereof. The first limb is bifurcated (Fig. 2A) and the second limb has a portion 18A which protrudes through the hole 9 (Fig. 2C) and a tag portion 18B to which a wire may be connected. All the components 16 (Figs. 2A, 2C) are accommodated in the two spaces lying on each side of the bus-bars 13 and bounded by the inner vertical rows of terminals 18 (Fig. 2A). Assembling mounting plates to form a translator. Each mounting plate 8 (Fig. 2) has at its top left-hand corner an assembly 14 including a stop member 14A which, when the plate is inserted into the mounting framework of Figs. 3, 3A, engages the stop assembly 27 (Fig. 3). At the same time the spring catch 15 (Fig. 2) engages the lower runner 26 (Figs. 3, 3A). The framework can accommodate four packs each of twelve translation mounting plates P (only one of which packs is shown in Fig. 3A), adjacent packs being separated by a terminalcarrying separator plate PS, and there being a single terminal-carrying test plate PT adjacent the pressure plate PP. The separator plates PS and the end plate PN carry no components and have no vertical rows of through-connecting terminals ; the test plate PT carries no components and the terminals in the vertical rows have no contact-making parts 18A; and the dummy end plate PD has no components and no through-connecting terminals. The end plate PN and the dummy end plate PD are held together and secured to the strut 24 of the framework by self-tapping screws 41. The plates P, PS, and PT are then inserted and finally the pressure plate PP. This plate, which is slightly smaller than the others, is secured to and carried by two metal struts 28 each of which has at each end a ferrule 28A threaded upon one of four lead screws 29. The lead screws are driven by a chain 39 via sprocket wheels 40, the chain itself being driven by the driving sprocket 32 associated with the hand wheel 31.