| 摘要 |
1518688 Automatic exchange systems WESTERN ELECTRIC CO Inc 5 Sept 1975 [9 Sept 1974] 36739/75 Heading H4K In a telecommunications exchange the main distribution frame (MDF) comprises a multi-stage cross-point switching network and there is provided a control arrangement which is capable of determining an exclusive path through the network and which controls an actuator device which sets up the path. Each switching stage comprises a plurality of modules 22, and the basic unit of each module is a switch 20. As shown each switch has 64 inlets and 64 outlets (i.e. 64 x 64 cross-points), and the complete MDF has a maximum capacity of 262, 144 inputs (64 modules each containing 64 switches) and the same number of outlets. The modules are assembled in racks, Figs. 4 and 5 (not shown) which in turn are assembled into an array of interconnected cabinets to form the MDF, Fig. 10 (not shown). For a given number of centre modules 23, the MDF may be expanded by adding a suitable number of outer "growth modules" (stages 1, 2, 4 and 5) when needed. Each switch 20 comprises a printed circuit board 61 having an array of pin terminals 62 extending from one or both sides thereof. The terminals are associated with conductors which enter the board through lands 63. The conductors can be interconnected with each other by interconnecting appropriate pins, e.g. by placing therebetween a connector 65. The conductors are also connected to test lands 66. In use, the switches 20 are slidably mounted in racks. When the control arrangement has determined an exclusive path between an input and an output terminal it forwards instructions to the actuator device. This latter includes a connector placement head (112) Fig. 11(not shown) for each network stage, each head being movable with respect to the associated cabinet by a coordinate drive arrangement, Fig. 10 (not shown). Under instructions from the control arrangement the heads are moved into position to slide out the appropriate switches and set up the required crosspoint connections for the exclusive path. When each connection has been made, a test is conducted on it utilizing the test lands 66 on the circuit board to which test conditions, e.g. different voltage levels, can be applied via the actuator device from a testing assembly (8, 12). The control arrangement includes a memory map in the form of a magnetic drum for storing details of all connections through the MDF.
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