Patent ID: 7788476

Claim:
A system comprising: a first module of a first chain of modules, each adjacent pair of said first chain of modules communicatively coupled in series to a programmable logic controller (PLC), said first module comprising a transmitting circuit, a receiving circuit, and repeater circuits, said first module adapted to communicate with said PLC via 8B/10B encoded frames, said first module comprising a first repeater which repeats transmissions from the direction of the PLC to a second module of said first chain of modules, said first repeater comprising a first switch, said first switch adapted to default to an open position prior to an assignment of a module address to said first module by said PLC, said first switch adapted to remain in said open position until said module address is assigned to said first module, said first module further comprising a second repeater which repeats transmissions from the direction of the second module to the direction of the PLC, said second repeater comprising a second switch selecting whether communication toward the PLC is from the first module transmission circuit or repeated from the second module.