Abstract: A method and apparatus are provided for implementing a redundancy enhanced differential signal interface. A differential signaling I/O pair is coupled to a differential receiver interface. The differential receiver interface includes a pair of multiplexers coupled to a differential receiver. An error detecting mechanism is coupled to the differential receiver for detecting an error. When an error is detected, an interface operating speed is reduced. True and complement sides of a differential signaling I/O pair are alternately tested by first enabling a multiplexer control of one of the multiplexers, reading data, and checking for the error; then enabling a multiplexer control of the other multiplexer, reading data, and checking for the error. Responsive to detecting a failure of a true side or a complement side, the detected failed true side or complement side is set to a reference voltage and the reduced interface operating speed is maintained for continued operation.

Abstract: A connector for attaching a printed circuit board to other apparatus is formed as a separate connector body with a plurality of pins projecting from one end surface that are attached to the printed circuit board by being secured in vias through the board and a threaded opening at the end surface opposite the one end surface from which the pins project. When a bolt is received in the connector threaded opening and drawn tight to secure the printed circuit board to other apparatus, the stresses and material deformation induced by the securing bolt are isolated from the printed circuit board. Further, the attachment of the pins to the printed circuit board rather than the use of screws extending through holes in the circuit board reduces the size of ‘keep out’ zones that must be avoided by the wiring paths on each wiring surface of the printed circuit board through which mounting holes extend.

Abstract: Described is a preferred structural panel including a frame and elongate members movably engaged by edges of the frame. Sheet material is bonded to the movably engaged elongate members and covers each side of the frame. In this manner, differential expansion among components of the frame and the sheet material can be accommodated by movement of the elongate members. Also described are preferred sheet material support systems and I-beam members.