jtag testing unit connector as shown in fig4 a generally an amc connector is set in an area 1 and the jtag testing unit connector is set in an area 2 of the full height single width amc slot as shown in fig4 b the amc connector is set in the area 1 and the jtag testing unit connector is set in an area 3 of the half height double width amc as shown in fig4 c the amc connector is set in the area 1 and the jtag testing unit connector is set in an area 4 of the full height double width amc or set in an area 2 or an area 3 thereof it should be noted that the jtag testing unit connector may be set into any amc slot the configuration of the jtag testing unit connector is described below in detail through an embodiment fig5 is a connection relationship diagram of a jtag testing unit connector according to an embodiment of the present invention as shown in fig5 a jtag testing unit connector is set in an area 2 of a full height single width amc of a microtca system and the jtag testing unit connector provides a star topological connection to the amcs and the mchs in the microtca system that is the connection wiring between units of the backplane is in a star topology manner once a jsm is plugged the jsm is located on a central node of the star topological connection fig5 adopts active standby redundant mchs that is adopts two mchs namely an mch 1 and an mch 2 thus a jtag control unit for controlling a jtag testing unit may.