PDH and SDH Alarms: LOS, LOF, AIS, RDI and Error Counts
Identify the interface and layer behind PDH or SDH alarms, trace AIS and RDI directions, and verify recovery using errors and actual tributary services.
PDH RLB Loopback Tests: Coverage, Errors and Service Recovery
Define the PDH RLB return point before testing. Compare the returned bit sequence, state which interfaces are excluded, then remove loopback and restore service.
Analog Fiber Link Troubleshooting: Readings, Errors and Hold
Locate analog fiber faults using known input points, output load checks and PLC scaling, while distinguishing a held output from a fresh measurement.
RS485 Hub Troubleshooting: Wiring, Timing and Fault Isolation
Locate RS485 hub faults using request/reply timing, minimal-branch comparisons and valid messages, then verify recovery of isolated and healthy channels.
Contact-over-Fiber Troubleshooting: Inputs, Links and Outputs
Trace contact-over-fiber faults from recognized input through optical delivery to the actual output loop, separating indicators, load power and software state.
E1 PCM Troubleshooting: Lines, Timeslots, Phones, and Boards
Locate PCM faults across power, E1 timing, channel mapping and subscriber interfaces. Preserve evidence before replacing boards or resetting settings.
E1 Converter Troubleshooting: LOS, AIS, Alignment, and Loopback
Trace LOS, AIS, frame alignment and clock slips along the actual E1 service. Save both-end evidence and define loopback coverage before testing.
HDMI Fiber Extender Troubleshooting: EDID, HDCP, and Bandwidth
Diagnose HDMI black screens with fixed-mode direct, short-fiber and installed-path comparisons. Save display-capability policy, audio and recovery evidence.
Troubleshooting Isolated Ethernet Fiber Channels
Troubleshoot isolated Ethernet fiber channels with per-path evidence. Separate optical loss, shared-load limits and forbidden cross-channel forwarding tests.
Reading Switch Fault Counters: Bad Frames, Queue Discards and CPU Load
Separate received frame errors, egress queue drops and control-plane load. Compare counter deltas and timestamps before diagnosing switch packet loss.
