IEC 62149-5:2009 specifies performance on the transceiver modules for asynchronous-transfer-mode passive optical network (ATM-PON) systems recommended by the International Telecommunication Union (ITU) in ITU-T Recommendation G.983.1. The main changes with respect to the previous edition are: - Normative references have been updated; - Incorrect "Letter symbols" have been corrected; - Some "Notes" in tables have been revised in order to harmonize with IEC 62150-2 (2004).