The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 04, 1995
Filed:
Mar. 10, 1993
Michael R Novakovich, Pittsburgh, PA (US);
Joseph S Majewski, Pittsburgh, PA (US);
AEG Transportation Systems, Inc., Pittsburgh, PA (US);
Abstract
A method A and apparatus for monitoring and switching over from a primary bus to a back-up bus in a network having a master node and at least one slave node, the primary bus and the back-up bus each interconnecting the master node and the at least one slave node. The method includes periodically sending via the back-up bus from the master node to each of the slave nodes a master test packet containing a master address of the master node on the back-up bus and sending on the back-up bus from the at least one slave node to the master node and in response to receiving the master test packet, a slave test packet containing a slave address of the at least one slave node on the back-up bus. The method further includes indicating failures on the primary and back-up bus and disconnecting the primary bus from the master node and the at least one slave node and resuming communications between the master node and the at least one slave node via the back-up bus when a failure occurs on the primary bus and no failures occur on the back-up bus.