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TC8116
User's Manual
Rev. 5.6D
Chapter 3 - Troubleshooting
General
Alarm conditions occur whenever an optical problem or "fault" condition is detected by the TC8116. Under
normal operation, all LEDs should be lit, with the exception of the "ALM," "USE RxB" and inactive channel
LEDs.
All LEDs are Off
If no LEDs are lit on the unit, check the DC power supply, connector plug, and/or the power source. If the
problem persists, contact the Technical Support Department at TC Communications, Inc.
Alarm LED
The "ALM" LED will light when an optic fault condition exists (such as a cable breakage or a poor optic
connection).
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.
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.
*These numbers are listed for reference only. We recommend an OTDR reading be used to determine actual link loss.
These are the reference values we use to calculate the loss on the fiber:
Multimode 850nm
:
3 dB loss per km on 62.5/125µm cable*
Multimode 1310nm
:
2 dB loss per km on 62.5/125µm cable*
Single Mode 1310nm
:
0.5 dB loss per km on 9/125µm cable*
Single Mode 1550nm
:
0.25 dB loss per km on 9/125µm cable*
