In NMEA 2000, what is the role of a talker device?

• A. To request data from other devices only.
• B. To configure network addresses.
• C. To publish data via PGNs on the network.
• D. To supply power to the bus.

Answer: (C)

In NMEA 2000, a talker is the source of data on the bus. Its job is to generate and broadcast data by publishing PGNs (Parameter Group Numbers) onto the network so other devices can receive and interpret that information. It does not request data from others, it does not set or manage network addresses, and it does not supply power to the bus. A GPS receiver, for example, acts as a talker by periodically sending position/velocity PGNs that any listening display or data logger can subscribe to. The power for the devices comes from the main power supply on the vessel, not from the talker itself.