Information Technology Reference
In-Depth Information
FIGURE 11.12
Fiber outlet with storage for extra fiber.
the basic continuity test of copper cable. The simplest source is a flashlight (possi-
bly with a fiber cable adapter), and the simplest detector is the human eye (Fig.
11.13). Following the safety practices in the next section, be certain you know that
a low-power visible light source is being used for this test and, even then, don't look
directly into the end of the fiber.
However, as with copper cable, a much more complex test is needed to deter-
mine proper operation of the fiber link. This is accomplished with a fiber-optic cable
scanner, as shown in Fig. 11.14. In some cases, the scanner may be an adapter mod-
ule that is used with a copper cable scanner.
However, because copper scanning is inherently more complex and expensive,
and because different cable crews may be involved in installing fiber-optic cables,
you may want to purchase a separate fiber-optic tester.
All fiber-optic cable testers for field use have a local and remote unit. The local
unit sends light of a known intensity down the cable under test. The remote unit
senses the absolute magnitude of the received light and calculates the loss. A
pass/fail indication is made and may be a function of the length of the cable. The
remote may be totally passive (to the installer) and simply report the results to the
