Field devices are a key component in intelligent transport systems (ITS). Field devices include traffic signals, message signs, weather stations, traffic sensors, roadside equipment for connected ITS (C-ITS) environments, etc.Field devices often need to exchange information with other external entities (managers). Field devices can be quite complex, necessitating the standardization of many data concepts for exchange. As such, the ISO 20684 series is divided several individual parts.This document specifies the needs, requirements and design for multiple mechanisms to fire triggers, which result in the device attempting to perform an action. Specific types of actions are defined in other documents and can include sending notifications (ISO/TS 20684-4), entering data into a log for later retrieval (ISO/TS 20684-5), and/or initiating SNMP-based requests (ISO/TS 20684-6).NOTE 1 There are similarities between certain portions of NTCIP 1103 and NTCIP 1201 and this document.NOTE 2 ISO 20684-1 provides additional details about how the ISO 20684 series relates to the overall ITS architecture.