802.5-1989 - IEEE Standard for Local Area Networks: Token Ring Access Method and Physical Layer Specifications
Description: This revised ANSI/IEEE 802.5-1985 is part of a standards family for LANs. For the purpose of compatible interconnection of data processing equipment via a LAN using token-passing ring access method, this standard defines the frame format and introduces medium access control (MAC) frames, timers and priority stacks. MAC protocol and the physical layer functions are defined. It describes the services provided by the MAC to the station management (SMT) and the logical link control sublayer (LLC) and services provided by the physical layer to SMT and the MAC. It also defines the 4 and 16 Mbit/s, shielded twisted pair attachment of the station to the medium including the medium interface connector (MIC). It specifies the homogeneous externally visible characteristics needed for interconnection compatibility avoiding internal design changes and constraints on heterogeneous processing equipment interconnection. The applications for the LAN are intended to be commercial and light industrial environment.