Cisco 2948G Hardware Installation Guide - Page 84

Installing, Removing, and Maintaining GBICs Chapter 4 Configuring the Gigabit Ethernet Ports Step 3 Step 4 Slide the GBIC out of the slot. Install the plug into the GBIC optical bores and place the GBIC in its protective packaging. GBIC Maintenance Guidelines Follow these GBIC maintenance guidelines: • GBICs are static sensitive. To prevent ESD damage, follow your normal board and component handling procedures. • GBICs are dust sensitive. When the GBIC is stored or when a fiber-optic cable is not plugged in, always keep plugs in the GBIC optical bores. • The most common source of contaminants in the optical bores is debris picked up on the ferrules of the optical connectors. Use an alcohol swab or Kim-Wipe to clean the ferrules of the optical connector. Patch Cord When using the LX/LH GBIC with a 62.5-micron diameter core size 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. The patch cord is required for link distances greater than 984 feet (300 meters). Note We do not recommend using the LX/LH GBIC with MMF without a patch cord for very short link distances (tens of meters). The result could be an elevated bit error rate (BER). Note The patch cord is required to comply with IEEE standards. The IEEE found that link distances could not be achieved 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 4-10 Catalyst 2984G, 2948G-GE-TX, and 2980G Switch Hardware Installation Guide 78-6286-05