Contains the requirements for data communication between maritime electronic instruments, navigation and radiocommunication equipment when interconnected via an appropriate system. Is intended to support one-way serial data transmission from a single talker to one or more listeners. This data is in printable ASCII form and may include information such as position, speed, depth, frequency allocation, etc. For applications where a faster transmission rate is necessary, reference should be made to IEC 61162-2. Is closely aligned with NMEA 0183 version 3.01. The main changes with respect to the previous edition include among others: - Clause 7 (Clause 5 in the previous edition) has been expanded to include two types of start of sentence delimiters. The conventional delimiter ""$"" is used with the conventional sentences which are now called parametric sentences. A new delimiter ""!"" identifies sentences that conform to special purpose encapsulation.