TC Communications TC8518 T1, Руководство пользователя

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Chapter 6 Troubleshooting Optic Cable Types
TC8518 Rev 2.2 User Manual 6-3
6.4 Optic Cable Types
Conventionally, fiber optic cable with yellow-colored insulation is used for Single
Mode applications; gray or orange-colored insulated cable is for Multimode use. If
Multimode cable is used in a Single Mode application, the test results could be
erroneous and confusing.
6.5 Calculating the loss on the Fiber
The fiber optic link and/or connectors are frequently the source of various problems.
Check out the connectors and the integrity of the link first. Ideally, the link should
be calibrated for total loss after the installation has been completed. This will
accomplish two things: (1) it will verify that the total loss of the link is within the
loss budget of the device and (2) it will provide a benchmark for future testing. For
example, a system that has been tested as having 6dB total loss when installed and
suddenly tests out as having a loss of 10dB probably has a connector or link
problem.
Figure 6-5 Reference for Calculating Fiber Loss
6.6 Loopback Tests
Loopback tests assist troubleshooting by helping in pinpointing the source of error.
The TC8518 is a sophisticated product designed with multiple advanced
technologies. Loopback tests have been implemented to test independent
components of it.