ATOP’s APS8CxxB53xDL20 single-mode transceiver is SFP28 module for duplex optical data communications support up to 25.78Gb/s. It is with the SFP+ 20-pin connector to allow hot plug capability. Digital diagnostic functions are available via an I2C. It has builtin clock and data recovery (CDR). This module is designed for single-mode fiber and operates at a nominal wavelength of CWDM (1271~1311nm).