SeaTalk is a simple interface for networking Raymarine/Autohelm marine equipment so that all devices of a ship can exchange and share their data. SeaTalk is a proprietary solution of Autohelm and not compatible with NMEA or CAN. Unfortunately Raymarine keeps the technical details of SeaTalk secret. To assist users who want to develop hard- or software to connect their devices to the SeaTalk bus these pages uncover some of the mysteries. Part 3 adds hints how to interface SeaTalk with a PC.