The time of a second network is synchronized to a first network, each network having an independent timing subsystem, includes the following steps. The first network sends a first message to the second network, the first message being uniquely identified as a sync message. A first relative time is obtained...http://www.google.de/patents/US5384563?utm_source=gb-gplus-sharePatent US5384563 - Method and apparatus for time synchronization of bus type local area networks including hierarchical networks
