An apparatus and method that captures a complete history of serial network Link Training negotiations by continuously monitoring multiple analog signals representing both sides of full duplex lanes in real-time by pattern matching the Link Training Frame Marker and the subsequent negotiation request/response data values. The apparatus and method compare the digitized version of the incoming signal against a nominal pattern at the start to find the Frame Markers and Control Channel data, storing only those Control Channel data values that do not match the current compare pattern, and further by updating the current compare pattern to the new pattern just received, so that only the transitions in the data values are stored, thereby vastly reducing the amount of data presented to the user, but nonetheless retaining the complete substantive history of the Link Training negotiations.