US 6,982,954 B2
Communications bus with redundant signal paths and method for compensating for signal path errors in a communications bus
Sang Hoo Dhong, Austin, Tex. (US); and Harm Peter Hofstee, Austin, Tex. (US)
Assigned to International Business Machines Corporation, Armonk, N.Y. (US)
Filed on May 03, 2001, as Appl. No. 9/848,175.
Prior Publication US 2002/0163881 A1, Nov. 07, 2002
Int. Cl. G01R 31/08 (2006.01)
U.S. Cl. 370—225 22 Claims
OG exemplary drawing
 
1. A communications bus connected between a source node and a destination node, the communications bus including:
(a) a number of alternate transmission paths extending between the source node and the destination node on a common substrate comprising a semiconductor chip;
(b) a source switching arrangement interposed between the source node and the alternate transmission paths, the source switching arrangement being operable to selectively connect the source node to a selected one of the alternate transmission paths and disconnect the source node from each other alternate transmission path;
(c) a destination switching arrangement interposed between the destination node and the alternate transmission paths, the destination switching arrangement being operable to selectively connect the destination node to the selected one of the alternate transmission paths and disconnect the destination node from each other alternate transmission path; and
(d) test circuitry connected to the source node and the destination node for applying a test signal to the selected one of the alternate transmission paths and for monitoring the destination node to determine whether the test signal is properly received at the destination node, wherein when the test signal is not properly received at the destination node the source switching arrangement disconnects the source node from the selected one of the alternate transmission paths and connects the source node to a respective one of the other alternate transmission paths, and the destination switching arrangement disconnects the destination node from the selected one of the alternate transmission paths and connects the destination node to the respective one of the other alternate transmission paths.