INTRODUCTION1-1CHAPTER 1INTRODUCTIONWelcome to the TRFMIM Token Ring Fiber Media InterfaceModules Installation Guide. This manual serves as a reference forinstalling and troubleshooting Cabletron Systems TRFMIM-22™,TRFMIM-26™, and TRFMIM-28™.The TRFMIM is a fiber optic token ring concentrator module for usein the Cabletron MMACs. These concentrators are designed incompliance with the IEEE 802.5J token ring fiber optic standard.Available with six, twelve or eighteen ports, the TRFMIM providesconnectivity over multimode fiber optic cable.Note: The term Concentrator Module is used throughout this manualwhen describing features and functions that are common to theTRFMIM-22, TRFMIM-26, and TRFMIM-28. The terms TRFMIM-22,TRFMIM-26, and TRFMIM-28 are used when it is necessary to describefeatures that are unique to any device.1.1 USING THIS MANUALPrior to installing and operating your concentrator module, readthrough this manual completely to familiarize yourself with itscontents and to gain an understanding of the features of theconcentrator module.A general working knowledge of Token Ring (IEEE 802.5) networkswill be helpful when installing your concentrator module.Chapter 1, Introduction, describes how to use this document,provides an overview of the features and capabilities of eachconcentrator module, and concludes with a list of related manuals.Chapter 2, Installation Requirements/Specifications, lists thenetwork requirements that must be met before you begin installing