Visual inspection identifies contamination, scratches, cracks, and endface defects that directly affect optical performance. Insertion loss testing measures the total optical loss of a fiber cable or. This recommended practices document is a comprehensive manual for optical fiber construction and testing. Sections are included for project management; cable handling, testing and equipment; overhead cable placement; underground cable placement; underground enclosures; bonding and grounding; cable. Testing fiber cable quality is a mandatory engineering process, not an optional best practice. Quality verification ensures that optical fibers meet attenuation, continuity, geometry, and mechanical integrity requirements before being placed into service. These systems are critical to ensuring robust and high-speed communication networks.