This document defines the broadband fieldbus specification AUTBUS. AUTBUS implements real-time, high reliability and deterministic transmission and application for both industrial fieldbus data and ISO/IEC/IEEE 8802-3 Ethernet data by shared medium bus.This document explains the structure and content of AUTBUS, and describes the definition and specification of Physical Layer (PhL) protocol / service, Data-link Layer (DLL) protocol / service and Application Layer (AL) protocol / service of AUTBUS.