IEC 61162-1:2024 contains the requirements for data communication between maritime electronic instruments, navigation and radiocommunication equipment when interconnected via an appropriate system. This document is intended to support one-way serial data transmission from a single talker to one or more listeners. These data are in printable ASCII form and can include information such as position, speed, depth, frequency allocation, etc. Typical messages can be from about 11 to a maximum of 79 characters in length and generally require transmission no more rapidly than one message per second. The electrical definitions in this document are not intended to accommodate high-bandwidth applications such as radar or video imagery, or intensive database or file transfer applications. Since there is no provision for guaranteed delivery of messages and only limited error checking capability, it is important this document is used with caution in all safety applications. For applications where a faster transmission rate is necessary, IEC 61162-2 applies. For applications to shore based equipment of the automatic identification system (AIS) the IEC 62320 series applies.