信息技术 通用数字音频-可视系统 第4部分:低层协议和物理接口

[中文适用范围]： ISO/IEC 16500 的这一部分提供了一个由较低层协议和物理接口组成的工具箱。 每种工具都适用于输送系统内的一个或多个参考点。 此版本的 ISO/IEC 16500-4 已确定的物理传输介质是铜线对、同轴电缆、微波、光纤和卫星。 携带物理介质（例如光盘和磁带）的可移动信息不包括在内。 列出的工具涉及传输系统的三个部分，即核心网络、接入网络和与接入网络无关的机顶单元 (STU) 接口。 还确定了用于 STU 数据端口接口、服务提供商系统 (SPS) 内部网络和 SPS/SPS 核心网络的工具。 第 6 条详细规定了为核心网络中的物理介质进行数字化所提供的工具。 在宽带核心网络的情况下，所有这些工具都支持高速ATM传输。 第 7 条详细规定了为接入网络中的物理介质（铜线对、同轴电缆、卫星、微波、光纤）进行数字化所提供的工具。 所有这些工具都支持高速 MPEG-2-TS 传输和/或高速 ATM 传输。 第 8 章涉及 STU 的独立于接入网络的接口，并提供网络接口单元 (NIU) 和 STU 之间物理接口的详细规范。 该物理接口可以位于机顶盒（STB）的内部或外部，并且独立于接入网络中使用的物理接口。 它支持NIU和STU之间的MPEG-2-TS和ATM传输。 第 9 条涉及 STU 数据端口接口，并指定用于将 STB 连接到各种外围设备的物理接口。 它定义了规范的 STU 多媒体数据端口工具和接口，还包括 PC 和并行数据端口的信息规范。 这些接口支持 MPEG-2-TS 或 IP 的传输。 第 10 条定义了级联 SPS 实体（有或没有中间核心网络）之间互连的物理接口，以及用于连接 SPS 内各种主机的网络的物理接口。 [外文原描述]： This part of ISO/IEC 16500 provides a toolbox consisting of lower layer protocols and physical interfaces. Each tool is applicable at one or more of the reference points within the delivery system. The physical delivery media that have been identified for this version of ISO/IEC 16500-4 are copper pairs, coaxial cable, microwave, fiber and satellite. Removable information carrying physical media (e.g. optical discs and tapes) are not covered. The tools listed address the three parts of the delivery system, namely, the core network, the access network and the access-network-independent interface to the Set Top Unit (STU). Tools are also identified for the STU dataport interface and for a service provider system (SPS) internal network and an SPS/SPS core network. Clause 6 specifies in detail the tools provided to digitize the physical media in the core network. In the case of a broadband core network, all these tools support high speed ATM transport. Clause 7 specifies in detail the tools provided to digitize the physical media in the access network (copper pairs, coax, satellite, microwave, fiber). All these tools support high speed MPEG-2-TS transport and/or high speed ATM transport. Clause 8 concerns the access-network-independent interface to the STU and provides a detailed specification of the physical interfaces between the network interface unit (NIU) and the STU. This physical interface can be internal or external to the Set Top Box (STB) and is independent from the physical interface used in the access network. It supports the transport of MPEG-2-TS and ATM between NIU and STU. Clause 9 concerns the STU dataport interface and specifies the physical interfaces used to connect an STB to various peripheral devices. It defines normative STU multimedia dataport tools and interfaces and also includes informative specifications for both PC and parallel dataports. These interfaces support the transport of MPEG-2-TS or IP. Clause 10 defines the physical interfaces for interconnections between cascaded SPS entities with or without an intervening core network and the physical interfaces for networks used to connect various hosts within an SPS.