High density pin board matrix switches for automated MDF systems

High-density, low-cost pin board matrix switches for automated main distributing frame (MDF) systems are described. The MDF system has two basic functions, cross connection and route setting for line test functions. These two functions can be performed automatically using a robot hand to insert a connecting pin into a crosspoint hole on the matrix board. Each crosspoint hole has four isolated cylindrical contacts that are connected to X/sub A/, Y/sub A/, X/sub B/, and Y/sub B/ conductive patterns, which represent the A and B wires of a telephone set circuit. Corresponding to the four contacts of a crosspoint hole, a connecting pin has two spring contacts, one spring contact to connect X/sub A/ and Y/sub A/ conductive patterns, and the other for connecting X/sub B/ and Y/sub B/ conductive patterns. In addition, arrangements have been made to perform the route setting for line testing. A matrix board with crosspoint holes on a 1.5-mm grid has been attained using the low-contact-force design and minimum insulation spacing between the neighboring conductive patterns. The design also considers requirements for the robot hand interface. These pin board matrix switches allow the MDF system to be automated.<
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