Cisco Catalyst 2970 Hardware Installation Manual page 44

Preparing for Installation
Table 2-1 Fiber-Optic SFP Module Port Cabling Specifications
SFP Module
CWDM
1. A mode-conditioning patch cord is required. Using an ordinary patch cord with MMF, 1000BASE-LX/LH SFP modules, and
a short link distance can cause transceiver saturation, resulting in an elevated bit error rate (BER). When using the LX/LH
SFP module with 62.5-micron diameter MMF, you must also install a mode-conditioning patch cord between the SFP module
and the MMF cable on both the sending and receiving ends of the link. The mode-conditioning patch cord is required for link
distances greater than 984 feet (300 m).
2. 1000BASE-ZX SFP modules can reach up to 62 miles (100 km) by using dispersion-shifted SMF or low-attenuation SMF;
the distance depends on the fiber quality, the number of splices, and the connectors.
Catalyst 2970 Switch Hardware Installation Guide
2-6
Wavelength
(nanometers) Fiber Type
1470, 1490, SMF
1510, 1530,
1550, 1570,
1590, 1610
When using shorter lengths of single-mode fiber cable, you might need to
Note
insert an inline optical attenuator in the link to avoid overloading the
receiver.
When the fiber-optic cable span is less than 15.43 miles (25 km), you
should insert a 5-decibel (dB) or 10-dB inline optical attenuator between
the fiber-optic cable plant and the receiving port on the 1000BASE-ZX
SFP module at each end of the link.
Operating environment is within the ranges listed in
•
Specifications."
Clearance to front and rear panels is such that
•
Front-panel indicators can be easily read.
–
Access to ports is sufficient for unrestricted cabling.
–
Rear-panel power connector is within reach of an AC power receptacle.
–
• Cabling is away from sources of electrical noise, such as radios, power lines,
and fluorescent lighting fixtures. Make sure the cabling is safely away from
other devices that might damage the cables.
Modal
Core Size Bandwidth
(micron) (MHz/km)
9/125 —
Chapter 2 Switch Installation
Cable Distance
62 miles (100 km)
Appendix A, "Technical
OL-6422-01