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Installation and Configuration Note for the Catalyst 4000 Layer 3 Services Module
78-10164-03
Gigabit Interface Converters
GBIC Optical Power Characteristics
Table 8 provides the optical power characteristics of the GBIC.
GBIC Cabling Restrictions
You must observe the following optical-fiber cabling restrictions when using GBICs:
•
The minimum cabling distance for 1000BASE-SX and 1000BASE-LX/LH GBICs is 6.5 feet
(2 meters).
•
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 whenever the
link distance is less than 100 meters or greater than 300 meters. For distances less than 100 meters,
the mode-conditioning patch cord reduces the amount of optical power coupled into the MMF. For
link distances greater than 300 meters, the mode-conditioning patch cord reduces differential mode
delay by offsetting the laser light. The mode-conditioning patch cord (CAB-GELX-625 or
equivalent) is required to comply with IEEE standards. The IEEE found that link distances could
not be met with certain types of fiber-optic cable cores. The solution is to launch light from the laser
at a precise offset from the center by using the mode-conditioning patch cord. At the output of the
patch cord, the LX/LH GBIC is compliant with the IEEE 802.3z standard for 1000BASE-LX.
•
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).
•
You must insert a 5-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 is greater than
15.5 miles (25 km), but less than 31 miles (50 km).
Table 8
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
3.4 dBm
4.4 dBm
N/A
62.5/125 micron MMF
3.2 dBm
6 dBm
N/A
9/10 micron SMF
n/a
6.5 dBm
21.5 dBm