SummaryRecommendation ITU-T G.9806 describes a higher speed bidirectional single fibre point-to-point optical access system than the data rate in existing ITU-T point-to-point access systems. It supports 10 Gbit/s for the optical access services including the optical distribution network (ODN) specification, the physical layer specification, services requirements and the operation, administration and maintenance (OAM) specification. Amendment 1 added support for 25 Gbit/s. Amendment 2 added support for 50 Gbit/s. Corrigendum 1 corrected a typo in Table 7-2.1 by replacing the current Mean launch power Maximum Class S "+5.6" value by "−5.6". Amendment 3 added support for 100 Gbit/s, optical path loss budget classes SL (0-10 dB), SU (5‑15 dB) and BL (10-20 dB). Corrigendum 2 made the following additions and corrections: 1) Added a keyword for 100 Gbit/s 2) Added a missing definition for Overload in clause 3 3) Replaced MAX/max with Maximum and MIN/min with Minimum as needed 4) Corrects the following typos: Table 7-1.3 • Correct Nominal modulation rate unit to "Gbaud" • Add "–" as the unit for modulation format and bit error ratio • Add missing unit "dBm" for Launch power in OMAouter minus TDECQ and Average launch power of OFF transmitter • Correct mean launch power Minimum for 1.4 dB ≤ TDECQ < 3.2 dB to "−1.8 + TDECQ" for Class S and "6.2 + TDECQ" for Class B– • Correct receiver Sensitivity for 1.4 dB ≤ TDECQ < 3.2 dB to "−17.3 + TDECQ" for both Class S and Class B– Table 7-1.4 • Correct nominal modulation rate unit to "Gbaud" • Add the missing unit for |TDECQ – TECQ| (Maximum): "dB" • Add "–" for the unit of modulation format and bit error ratio |