| 摘要 |
PURPOSE: A circuit for switching a routing on a switch board of an exchange is provided to test many ports with a CPU command by using a field programmable gate array(FPGA) and a programmable logic device(PLD) on the switch board. CONSTITUTION: A processor terminal(73) outputs an optical loopback signal applied from a CPU interface to a serial to deserializer converter of a switch board, and performs a loopback command. A down stream block comprises as follows. A switch input terminal(71) is applied with data from a switch interface. The second multiplexer(76) selects one of data applied from an up stream block and the data applied from the switch input terminal(71), according to second selection data applied from the processor terminal(73). A multiplexer output terminal(78) applies the selected data to a multiplexer interface. The up stream block comprises as follows. A multiplexer input terminal(72) is applied with the data applied from the multiplexer interface. A routing tag conversion logic(74) converts a data-typed switching tag field applied from the multiplexer input terminal(72), according to routing tag conversion command data of the processor terminal(73). The first multiplexer(75) selects one of the data of the down stream block and the data of the routing tag conversion logic(74), according to first selection data of the processor terminal(73). A switch output terminal(77) applies the selected data to the switch interface.
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