标准编号：ISO 14819-1:2021
中文名称：智能运输系统 通过交通信息编码的交通和旅行信息信息 第1部分：使用ALERT-C的无线电数据系统交通信息信道（RDS- TMC）的编码协议
英文名称：Intelligent transport systems — Traffic and travel information messages via traffic message coding — Part 1: Coding protocol for Radio Data System-Traffic Message Channel (RDS-TMC) using ALERT-C
发布日期：2021-03
标准范围
The ALERT-C protocol is designed to provide mostly event-oriented road end-user information
messages.
This document specifies the messages which are presented to the user in accordance with a set of
general requirements. It defines the message structure and content and its presentation to the end-user.
The message management component of this document describes the message management functions
of RDS-TMC. The ALERT-C protocol distinguishes between user messages and system messages. User
messages are those potentially made known to the end-user, as defined in Clause 5. System messages
are of use only to the RDS-TMC terminal, for message management purposes.
RDS-TMC information comprises both ‘system information’ and ‘user messages’. System information
relates to the TMC service and details the parameters that the terminal needs to be able to find,
identify and decode the TMC information. System information is transmitted in type 3A groups and in
type 8A groups.
User messages contain the details of the traffic events; these may use one or more type 8A groups. Most
messages may be transmitted using a single type 8A group, however messages with more detail (e.g.
diversion advice) may use up to a total of five, type 8A groups.
The transmission component of this document conveys the messages over-air. The ALERT-C protocol,
used by RDS-TMC, has the fundamental approach of aiming to code most messages entirely within a
single RDS group.
The ALERT-C Event List, which contains all event deions, is described in ISO 14819-2.
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