Abstract: Apparatus for making an electrical connection in a system requiring four electrical connections, including an electrical connection pad having an array of four types of electrically conductive contacts, all conductive contacts of a given type being electrically connected to all other conductive contacts of the same type; and an arrangement for providing electrical connections to conductive contacts on the pads, the arrangement having electrically conductive pins for making contact with the conductive contacts, wherein the types of electrically conductive contacts include two contacts for power and two separate contacts for signals. The pins may be arranged at corners of a first square and a second square, with the first square being rotated by forty-five degrees with respect to the second square, and a pin located at a common center of both squares. A method of operation of the apparatus, and various applications and configurations for its use.