B-11
Cisco 7600 Series Router Installation Guide
OL-4503-26
Appendix B Connector and Cable Specifications
Cable Specifications
Note
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.
Patch Cord Configuration Example
Figure B-9
shows a typical patch cord configuration.
Figure B-9
Patch Cord Configuration
Patch Cord Installation
Warning
Because invisible laser radiation may be emitted from the aperture of the port when no cable is
connected, avoid exposure to laser radiation and do not stare into open apertures.
Plug the end of the patch cord labeled “To Equipment” into the GBIC. (See
Figure B-10
.) Plug the end
labeled “To Cable Plant” into the patch panel. The patch cord is 9.84 feet (3 meters) long and has duplex
SC-type male connectors at each end.
Figure B-10
Patch Cord Installation
1000BASE-LX/LH
port
Patch
panel
Link span greater than 984 ft
(300 m)
1000BASE-LX/LH
port
Rx
Tx
Patch
panel
Patch
cord
Building
cable plant
Tx
Rx
Patch
cord
13088
To equipment
To cable plant
13089