Method and apparatus for full duplex serial shifting mode and switch mode data transmission

An industrial network with bidirectional communication for real time control includes nodes selectively operable in either a switch mode or a serial shifting mode. Nodes operating in the switch mode are capable of initiating data frames for transmission on the network and receiving data frames from the network. Nodes operating in either the switch mode or the serial shifting mode are capable of extracting and/or inserting data into a data frame as it is transmitted through that node. An initialization procedure determines end nodes and intermediate nodes within the network. The end nodes are configured to initially operate in the switch mode and the intermediate nodes are configured to initially operate in the serial shifting mode. The intermediate nodes are additionally operable to selectively toggle between operation in switch mode and serial shift mode and may operate in both modes during a single scan cycle.