Visual Fault Locators (VFL) are primarily used for:

Visual Fault Locators (VFL) are primarily utilized for identifying issues in optical fibers. They work by emitting a visible light, typically a red laser, through the fiber. When the light encounters a break, bend, or other physical defect within the fiber, it exits the cable at that point, allowing the technician to easily pinpoint where the problem lies. This visual confirmation helps in troubleshooting and repairing fiber optic installations efficiently.

While other techniques and instruments can test copper cables or verify circuit connections, they do not serve the same function as VFLs with optical fibers. Additionally, VFLs are not designed to measure network speed; they focus specifically on the integrity of fiber connections and identifying faults rather than assessing performance metrics like bandwidth or data transfer rates.