Abstract: Two types of connectors including a crossover connector and a test connector for a receptacle attached to two back-to-back planar circuitboards.The receptacle includes a plurality of apertures containing metallic leads which are attached to terminals on both printed circuitboards.One face of the crossover connector has a plurality of pins which are to be received into the apertures of the receptacle in order to connect any desired combination of terminals on the two printed circuitboards while simultaneously isolating the other terminals. The opposite face of the connector contains a plurality of apertures so that an electrical probe can have easy access to its interconnecting and isolating pins.The test connector includes two subassemblies, the first of which is comprised of an insulated body containing pin structures similar to the isolating pin structure of the crossover connector except that it contains pins which extend from both faces of its body.