IEC 62316, which is a Technical Report, aims to provide guidelines for the interpretation of backscattering traces, as obtained by traditional optical time domain reflectometers (OTDRs) not including polarization OTDRs - for single-mode fibres. Also, backscattered power effects are discussed in case of unidirectional trace. Full description of the test measurement procedure can be found in Annex C of IEC 60793-1-40:2001.