Installation guide

4-5

Catalyst 2984G, 2948G-GE-TX, and 2980G Switch Hardware Installation Guide

78-6286-04

Chapter 4 Configuring the Gigabit Ethernet Ports

Installing, Removing, and Maintaining GBICs

GBIC Cabling Restrictions

You must observe the following fiber-optic cabling restrictions when using

GBICs:

• The minimum cabling distance for 1000BASE-SX and 1000BASE-LX/LH

GBICs is 6.5 feet (2 meters).

• The maximum cabling distance for each GBIC type is listed in Table 4-2.

• When using the 1000BASE-LX/LH GBIC with 62.5-micron diameter MMF,

you must install a mode-conditioning patch cord between the MMF

fiber-optic network and the GBIC. The mode-conditioning patch cord

(CAB-GELX-625 or equivalent) is required to comply with IEEE standards.

See the “Patch Cord” section on page 4-10 for more information.

• You must insert a 10-dB inline optical attenuator between the single-mode

fiber-optic network and the receiving port on the 1000BASE-ZX GBIC at

each end of the link if the link length is less than 15.5 miles (25 km).

Table 4-3 GBIC Optical Power Characteristics

Parameter

1000BASE-SX

(WS-G5484)

1000BASE-LX/LH

(WS-G5486)

1000BASE-ZX

(WS-G5487)

Transmitter output power

(min/max)

0/–9.5 dBm –3/–9.5 dBm 0/4.77 dBm

Receiver maximum input

power

0 dBm –3 dBm –3 dBm

Receiver sensitivity –17 dBm –19 dBm –23 dBm

Channel insertion loss

50/125 micron

MMF

1. 1 micron (µ) equals 1 micrometer or 10

-6

meters

3.4 dBm 4.4 dBm –

62.5/125 micron MMF 3.2 dBm 6 dBm –

9/10 micron SMF – 6.5 dBm 21.5 dBm