The PLC 1756-CNBR, or ControlNet Bridge Redundancy, is an interface module used for communicating within a ControlNet Network. It is the same as the 1756-CNB but the biggest difference is that the 1756-CNBR has an additional ControlNet port, which will support redundant media. This module has 2 ControlNet BNC port while the 1756-CNB only has one, although both of them have 1 ControlNet RJ45 port.
Like the non-redundant module, the 1756-CNBR also controls scheduled data in conjunction to the Logix5550 Controller and bridges unscheduled data between the ControlLogix backplane and the ControlNet Network.
To prevent communication loss when a tap or trunkline is disconnected, a redundant ControlNet media can be used. For that connection, the only module you can use is the 1756-CNBR.
