a) To connect jack A to jack B on a patch bay with a patch cord.

b) A section of curved, non-planar surface; it can be likened to a rectangular rubber sheet which can be pulled in all directions. c) Section of coding inserted into a routine to correct a mistake or alter the routine. It is usually not inserted into the actual sequence of the routine being corrected, but placed somewhere else. A jump to the patch and a return to the routine are then provided.