Mode-Conditioning Patch Cord; Patch Cord Configuration Example - Cisco 7609-S Installation Manual

Appendix B Connector and Cable Specifications

Mode-Conditioning Patch Cord

Note

Patch Cord Configuration Example

Figure B-7 Patch Cord Configuration
Patch
cord
Rx
1000BASE-LX/LH
port
Tx
OL-5079-04
When using the long wavelength/long-haul (LX/LH) GBIC with 62.5-micron
diameter MMF, you must install a mode-conditioning patch cord (Cisco
product number CAB-GELX-625 or equivalent) between the GBIC and the
multimode fiber (MMF) cable on both the transmit and receive ends of the link.
The patch cord is required for link distances greater than 984 feet (300 meters).
We do not recommend using the LX/LH GBIC and MMF without the patch
cord for very short link distances of 33 to 328 feet (10 to 100 meters). The
result could be an elevated bit error rate (BER).
The patch cord is required to comply with IEEE standards. IEEE found that link
distances could not be met with certain types of fiber-optic cable due to a problem
in the center of some fiber-optic cable cores. The solution is to launch light from
the laser at a precise offset from the center by using the patch cord. At the output
of the patch cord, the LX/LH GBIC complies with the IEEE 802.3z standard for
1000BASE-LX.
Figure B-7 shows a typical patch cord configuration.
Building
cable plant
Patch
panel
Link span greater than 984 ft
(300 m)
Patch
cord
Tx
Patch 1000BASE-LX/LH
panel
Rx
Cisco 7609 Internet Router Installation Guide
Cable Specifications
port
B-13