A complete reference of OLT configuration, troubleshooting, and monitoring commands for GPON/EPON devices (ZTE, Huawei, V-SOL, etc. )ONU offline, optical link degradation, registration failure, slow speed diagnosis. Use optical power meter to test RX power, check DDM data on OLT. This repository serves as a technical knowledge hub for network engineers working with FTTH (GPON/EPON) infrastructure. It contains configuration commands, troubleshooting methods, power-check commands. If your problem is not USB related, troubleshooting printer problems is best handled in two easy steps: first diagnose the problem, then apply likely solutions until the problem is fixed. Provides step-by-step instructions for configuring VLANs, trunks, and ONUs. Check the fiber optic cable for damage and ensure it is securely connected to both the ONU and the optical network.