Two office switches power on, but the new fibre uplink stays down. Check that both switch ports, both optical modules and the installed fibre were specified to work together before replacing a switch or ordering another module.
Record the actual parts at both ends
Collect switch and port model numbers, module part numbers, intended speed and the fibre type and path. Check the switch vendor’s port and transceiver compatibility information. Modules that fit a similar-looking slot can require a different port speed or standard. Check both ends against the intended link speed and the module manufacturer’s specifications.
Ubiquiti’s fibre and transceiver guide illustrates the differences between single-mode and multimode fibre and how supported distance depends on the combination. Verify the markings and installation records rather than relying on jacket colour. For duplex optics, confirm the transmit path at one end reaches the receive path at the other. For single-strand bidirectional optics, confirm the modules are a complementary wavelength pair.
Isolate the switch, module and installed path
First check whether each switch reports the module and whether the port is enabled. During a planned change window, have a qualified technician try the intended pair on a known-good short path of the correct fibre type, within the modules’ optical limits. If that works, inspect the installed path, including patch panels and polarity. Where available, compare optical receive levels with the module’s published limits. Have the technician follow optical safety and connector cleaning procedures.
If the link comes up but the branch still cannot reach its systems, verify the expected VLANs and test end-to-end traffic. A link light confirms a physical connection. It cannot confirm that staff and voice traffic are reaching their destinations. The guide to office network configuration recovery explains what to capture before making changes.
Record the combination that passed
Document the working port configuration, module pair and patch path. Confirm negotiated speed, check error counters during a controlled transfer and record the result for future replacements.
ITZ’s office network setup service can review the switch models, installed fibre and target link. Share the module part numbers and the two switch models.
Review your office fibre uplink
Bring the switch and module details, fibre type if known and a description of what the ports report. Use the form to discuss a compatibility review and a test plan. Review Your Office Fibre Uplink
