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Cisco XR 12000 Series Router Ethernet Line Card Installation
OL-7861-01
Cabling and Specifications
Figure 42 Attaching Simplex or Duplex Fiber Cables (Line Card Port or GBIC)
Note The fiber-optic connectors must be free of dust, oil, or other contaminants. Carefully clean the fiber-
optic connectors using an alcohol wipe or other suitable cleanser.
Cleaning Fiber-Optic Connectors
Fiber-optic connectors are used to connect two fibers together. When these connectors are used in a
communication system, proper connection becomes a critical factor. They can be damaged by improper
cleaning and connection procedures. Dirty or damaged fiber-optic connectors can result in
communication that is inaccurate or not repeatable.
Fiber-optic connectors differ from electrical or microwave connectors. In a fiber-optic system, light is
transmitted through an extremely small fiber core. Because fiber cores are often 62.5 microns or less in
diameter, and dust particles range from a tenth of a micron to several microns in diameter, dust and any
other contamination at the end of the fiber core can degrade the performance of the connector interface
where the two cores meet. Therefore, the connector must be precisely aligned and the connector interface
must be absolutely free of foreign material.
Connector loss, or insertion loss, is a critical performance characteristic of a fiber-optic connector.
Return loss is also an important factor. Return loss specifies the amount of reflected light: the lower the
reflection, the better the connection. The best physical contact connectors have return losses of better
than –40 dB, but –20 to –30 dB is more common.
1 TX connector 3 Simplex cables
2 RX connector 4 Duplex cable
22553
FAST ETHERNET
Duplex
Simplex
TX
RX
17464
GBIC with simplex or
duplex SC connectors
Simplex
Duplex
RX
TX
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