Abstract: A switching matrix utilizing connection modules, for the connection of peripherally arranged electrical measuring devices, over selectable lines of a line group specifically associated with a matrix, to the peripheral terminals of specimens to be measured, such as electrical components, circuit board, assemblies, communication devices and the like, wherein the connection modules are designed with two poles, each of which is selectively connectable to a respective peripheral terminal of a specimen or a device over controllable switching means, and further controllable switching means for selectively connecting the first pole of a connection module to the second pole thereof at the matrix side of the first mentioned switching means associated with such second pole, in the event said last mentioned switching means is open, each of such poles providing access from such a terminal to separate line subgroups, from which a line is then selected over additional controllable switching means.