This document, together with its addenda, provides standards for the intermateability of fiber optic connectors. Each addendum to this document is a Fiber Optic Connector Intermateability Standard (FOCIS) for a particular type or design of fiber optic connector.

Fiber Optic Connector Intermateability Standards, FOCISs, are developed by Subcommittee FO 6.3 on Interconnecting Devices. They are approved jointly by EIA and TIA, and are issued as addenda to this document.

The intermateability requirements in a FOCIS apply to mating optical components such as connector plugs, adaptors, and receptacles. The intermateability requirements in a FOCIS are to be for completed product. For example, for a connector plug the requirements are to be the requirements for the plug mounted with the fiber installed and ready for use.