本标准描述了一种高速、低成本串行总线，适合用作外围总线、并行背板总线备份或局域网。串行总线的亮点包括: a） 总线事务，包括块和单四字节读写，以及a？等时性？提供低开销保证带宽服务的模式。 b） 保证所有节点平等访问的公平总线访问机制。背板环境增加了一个优先级机制，但该机制确保使用公平协议的节点仍然至少能保证部分访问。 c） 自动分配节点地址？无需地址开关。 d） 物理层（PHY）支持长途和短途电缆介质和背板总线。 e） 基于ISDN兼容1比特率的变速数据传输，从晶体管晶体管逻辑（TTL）背板的24.576 Mbit/s到背板收发器逻辑（BTL）背板的49.152 Mbit/s。对于电缆介质，支持98.304 Mbit/s（称为S100）、S200、S400、S800、S1600和S3200的数据传输速率。 f） 一种短途电缆介质，允许多达16个物理连接（电缆跳数），每个物理连接最多4.5米，使任何两个设备之间的总电缆距离达到72米。总线管理识别较小的配置以优化性能。 g） 一种长距离电缆介质，允许在非屏蔽双绞线（UTP）电缆和玻璃光纤（GOF）上进行长达100米的连接，在塑料光纤（POF）上进行长达50米的连接。 h） 与ISO/IEC 13213的一致性: 1994年（IEEE标准1212，1994年版）。

This standard describes a high-speed, low-cost serial bus suitable for use as a peripheral bus, a backup to parallel backplane buses, or a local area network. Highlights of the serial bus include the following: a)Bus transactions that include both block and single quadlet reads and writes, as well as an "isochronous" mode that provides a low-overhead guaranteed bandwidth service. b)A fair bus access mechanism that guarantees all nodes equal access. The backplane environment adds a priority mechanism, but one that ensures that nodes using the fair protocol are still guaranteed at least partial access. c)Automatic assignment of node addresses—no need for address switches. d)A physical layer (PHY) supporting both long-haul and short-haul cable media and backplane buses. e)Variable speed data transmission based on ISDN-compatible1 bit rates from 24.576 Mbit/s for transistor-transistor logic (TTL) backplanes to 49.152 Mbit/s for backplane transceiver logic (BTL) backplanes. For the cable medium, data transmission rates of 98.304 Mbit/s (known as S100), S200, S400, S800, S1600, and S3200 are supported. f)A short-haul cable medium that allows up to 16 physical connections (cable hops), each up to 4.5 m, giving a total cable distance of 72 m between any two devices. Bus management recognizes smaller configurations to optimize performance. g)A long-haul cable medium that permits connections up to 100 m in length over unshielded twisted pair (UTP) cable and glass optical fiber (GOF) and up to 50 m over plastic optical fiber (POF). h)Consistency with ISO/IEC 13213:1994 (IEEE Std 1212, 1994 Edition).