Allied Telesis AT-2746FX - Manual (Page 207)

Network Adapter Card Installation Guide
207
3. If a fiber inspection scope is available, use the scope to inspect the
connector to make sure that it is clean and to check for scratches, pits,
or other problems that may affect performance.
Note
Always keep a dust cap on a fiber optic cable when it is not in use.
Warning
Do not look directly at the fiber optic cable ends or inspect the cable
ends with an optical lens. 31