The Read-Only WDM GBIC (WDM-GBIC-REC=) has only one optical bore (receive).
Step 4
Immediately attach the network interface cable optical connector to the transceiver.
Always grasp the SC or the LC connector housing rather than the fiber-optic cable to plug or unplug the fiber-optic cable.
Mode-Conditioning Patch Cord
When using the long-wavelength and long-haul (LX and LH) GBIC with 62.5-micron diameter multimode
fiber (MMF), you must install a mode-conditioning patch cord (Cisco product number CAB-GELX-625 or
equivalent) between the GBIC and the MMF cable on both the transmit and receive ends of the link.
When an unconditioned laser source designed for operation on single-mode optical fiber (SMF) is directly
coupled to an MMF cable, an effect known as differential mode delay (DMD) might result in a degradation
of the modal bandwidth of the optical fiber cable. This degradation results in a decrease in the link span (the
distance between a transmitter and a receiver) that can be supported reliably. The effect of DMD can be
overcome by conditioning the launch characteristics of a laser source. A practical means of performing this
conditioning is to use a device called a mode-conditioning patch cord.
A mode-conditioning patch cord is required for 1000BASE-LX and LH applications over FDDI-grade, OM1,
and OM2 fiber-cable types. Mode-conditioning patch cords should not be used for applications over OM3
fiber cable (laser-optimized fiber cable). For more information about mode-conditioning patch cords, see the
Use of Mode Conditioning Patch Cables in Gigabit Ethernet and 10 Gigabit Ethernet Laser-Based Transmissions
bulletin available on Cisco.com.
Figure 12: Mode Conditioning Patch Cord with SC (GBIC Transceiver) Connector
MMF
6
Beige color identifier
1
Single-mode fiber (SMF)
7
To Gigabit Ethernet interface
2
Offset junction
8
RX (receiver)
3
To cable plant
9
TX (transmitter)
4
Blue color identifier
5
Catalyst 6800 Ethernet Module Installation Guide
32
Installing and Removing Modules, Transceivers, and Attaching Cables
Mode-Conditioning Patch Cord
