Carrier Sense Multiple Access / Non-destructive Bit-wise Arbitration (CSMA/NBA)

In PLC Communications, devices using CSMA/NBA first checks the media for the presence of a carrier (Carrier Sense), which indicates that another device is transmitting data. If the carrier is absent it then begins its transmission. If multiple devices begin transmissions simultaneously, each device’s unique identifier is used to choose who can transmit without destroying the identifier.

The DeviceNet protocol uses CSMA/NBA.