The Adtran SDX 600 Series of GPON optical network terminals (ONTs) are designed to address the demands of residential and business customers in the multigigabit era. The flexible, open technology provides a cost-effective path to high-bandwidth services while enabling service providers to support existing FTTP subscribers. Variants supporting 2.5GbE interfaces have the unique capability of fully supporting 1Gbit/s throughput speed testing.