Core contents of the standard: First, functional safety level requirements, clarifying that the fieldbus system of lifts and escalators must comply with ISO 13849 standard, the safety integrity level reaches PL d grade, and the fault diagnosis coverage rate is ≥98%; Second, communication protocol specification, unifying the technical requirements of the physical layer, data link layer and application layer of the fieldbus, and standardizing the core parameters such as data frame format, transmission rate, communication distance and number of nodes; Third, data transmission security, clarifying the data encryption, verification and retransmission mechanisms, requiring data transmission error rate ≤10-9, transmission delay ≤5ms, with anti-electromagnetic interference and data tampering prevention functions; Fourth, redundancy design requirements, safety-related communication systems must have redundant design, single-channel failure does not affect the system safety function, fault response time ≤100ms; Fifth, testing and verification, unifying the methods and judgment standards of functional safety test, communication performance test, environmental adaptability test and electromagnetic compatibility test, providing a unified basis for product R&D, certification and acceptance.