现场设备是智能交通系统（ITS）的关键部件。现场设备包括交通信号、信息标志、气象站、交通传感器、用于连接ITS（C-ITS）环境的路边设备等。 现场设备通常需要与其他外部实体（管理者）交换信息。现场设备可能非常复杂，需要对许多数据概念进行标准化以进行交换。因此，ISO20684系列分为几个单独的部分。 本文件规定了ISO其他部分规范使用的用户需求、要求和设计元素20684系列。具体而言，它定义了一个内部现场设备时钟，一种用于将对象值分组在一起以提供更有效的数据传输的机制，并提供了对SNMP目标和IETF RFC 3413中定义的目标参数的正式要求。 注释1NTCIP 1103和NTCIP 1201的某些部分与本文件有相似之处。 注2ISO 20684-1提供了关于ISO20684系列涉及整个ITS架构。

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 user needs, requirements and design elements that are normatively used by other parts of the ISO？20684 series. Specifically, it defines an internal field device clock, a mechanism for grouping object values together to provide for more efficient transfer of data, and it provides formal requirements for the SNMP target and target parameters as defined in IETF RFC 3413. 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.