Specifications

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Cisco ONS 15454 Troubleshooting and Maintenance Guide
November 2001
Chapter 2 General Troubleshooting
Step 5 If no power level shows on the fiber, the fiber is bad or the transmitter on the optical card failed.
a. Check that the Transmit (Tx) and Receive (Rx) fibers are not reversed. LOS and EOC alarms
normally accompany reversed Tx and Rx fibers. Switching reversed Tx and Rx fibers clears the
alarms and restores the signal.
b. Clean or replace the fiber patch cords. If possible, do this for the OC-N card you are working on and
the far-end card.
c. Retest the fiber power level.
d. If the replacement fiber still shows no power, replace the optical card.
Step 6 If the power level on the fiber is above the range specified for the card, ensure that an ONS long range
(LR) card is not being used when an ONS intermediate range (IR) card is appropriate.
LR cards transmit a higher output power than IR cards. When used with short runs of fiber, an LR
transmitter will be too powerful for the receiver on the receiving OC-N card.
Receiver overloads occur when maximum receiver power is exceeded.
Tip To prevent overloading the receiver, use an attenuator on the fiber between the ONS OC-N card
transmitter and the receiver. Place the attenuator on the receive transmitter of the ONS OC-N cards.
Refer to the attenuator documentation for specific instructions.
Tip Most fiber has text printed on only one of the two fiber strands. This can help clarify which strand is
Tx and which is Rx.
Procedure: Replace Faulty Gigabit Interface Converters
Gigabit interface converters (GBICs) are hot-swappable input/output devices that plug into a Gigabit
Ethernet port to link the port with the fiber-optic network. Cisco provides two GBIC models: one for
short reach applications, 15454-GBIC-SX, and one for long reach applications, 15454-GBIC-LX. The
short reach, or “SX” model, connects to multimode fiber and has a maximum cabling distance of 1804
feet. The long reach, or “LX” model, requires single-mode fiber and has a maximum cabling distance of
32,810 feet.
GBICs are hot-swappable and can therefore be installed or removed while the card and shelf assembly
are powered and running. GBIC transmit failure is characterized by a steadily blinking Fail LED on the
Gigabit Ethernet (E1000-2/E1000-2-G) card. Figure 2-15 shows a GBIC.
Figure 2-15 A gigabit interface converter (GBIC)
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Receiver Transmitter