GB/T 19244-2003 in English

《GB/T 19244-2003信息技术 高性能串行总线》由TC28（全国信息技术标准化技术委员会）归口，TC28SC25（全国信息技术标准化技术委员会信息技术设备互连分会）执行，主管部门为国家标准化管理委员会。
本标准描述高速、低成本串行总线。它适合于作外围总线或并行底板总线的备用总线。

Scope

This standard describes a high-speed, low-cost serial bus. It is suitable as a backup bus for peripheral bus or parallel backplane bus. Salient features of this serial bus include: a) Automatic assignment of node addresses - no address switches required. B) Variable rate data transmission based on ISDN-compatible bit rate, which can be changed from 24.576 Mbit/s of TTL backplane to 49.152 Mbit/s of BTL backplane, and 98.304 Mbit/s, 196.608 Mbit/s and 196.608 Mbit/s of cable media 393.216 Mbit/s. C) The cable medium allows up to 16 physical connections (cable hops) of up to 4.5 m per hop, giving a total cable distance of 72 1T1 between any two devices. Bus management can identify smaller configurations for optimal performance. D) Includes block and single four-byte reads and writes, and bus transactions in "isochronous" mode that provide low-overhead, guaranteed-bandwidth service. E) Physical layer supporting cable media and backplane bus. F) A fair bus access mechanism that guarantees equal access to all nodes. Backplane environments add a prioritization mechanism, but not one that ensures that nodes using a fair protocol still get at least unfair access. G) Coordinate with ISO/IEC l3213:1994 (IEEE std l212--1991).