PLANET GPON OLT SFP Quad (small form factor pluggable) Transceiver (GPL-GSFP) is specifically designed for high-performance integrated duplex data link over single mode optical fiber, and its single fiber bi-directional data links with symmetric 2.488Gbps Tx and 1.244Gbps Rx. It is compliant with ITU-T G.984.2 and hot pluggable.    The GPON OLT SFP Transceiver also supports SFP-DDM (digital diagnostic monitor) function that greatly helps network administrators to easily monitor real-time parameters of the SFP, such as optical output power, optical input power, temperature, laser bias current, and transceiver supply voltage.