The Fibre Distributed Data Interface (FDDI), ISO/IEC 9314, is intended for use in a high performance general purpose multistation network and is designed for efficient operation with a peak data rate of 100 Mbit/s. It uses a Token Ring Architecture with optical fibre as the transmission medium. FDDI provides for hundreds of stations operating over an extent of tens of kilometres. The FDDI Physical Media Dependent (PMD) standard, ISO/IEC 9314-3, specifies the lower sublayer of the Physical Layer for the FDDI, including the optical interface for multimode fibre FDDI stations. This part of ISO/IEC 9314 is an abstract test suite (ATS) conformance test for FDDI PMD. ISO/IEC 9314-3 specifies the optical interface of FDDI stations; it is not a protocol standard and this part of ISO/IEC 9314 requires the measurement of physical quantities such as optical power, wavelength and signal jitter. The intent of this part of ISO/IEC 9314 is to specify the tests as broadly as possible to allow measurement by various detailed test implementations.