
Page 21
M-UM010-02 TTK 720 06/18
An onboard red laser allows users to verify proper continuity of fiber cables. This is a troubleshooting
task only. This section gives an overview of the VFL functionality.
VFL Testing
5
The VFL port on the VIS 300C has a 2.5mm
universal output. Plug a fiber with a 2.5mm
ferrule completely into this port. When the VFL
is ON or modulating, red light will emanate
from the other end of the fiber (5km range) and
will leak from the fiber jacket at any breaks or
excessive bends in the fiber.
Touch the “VFL” button on the
main VIS 300C screen to toggle
between three modes.
VFL is OFF
VFL is ON
VFL is modulating at
2Hz. It will blink twice
per second.