Cisco WS-C2950T-48-SI Hardware Installation Manual page 32

Front-Panel Description
Table 1-2
SFP Module
1000BASE-SX
1000BASE-LX/LH
1000BASE-ZX
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 send 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.
When using shorter distances of single-mode fiber cable, you might need to insert an inline optical
Note
attenuator in the link to avoid overloading the receiver.
When the fiber-optic cable span is less than15.43 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.
Use only Cisco-approved SFP modules on the Catalyst 2950 LRE switch.
Cisco-approved SFP modules have a serial EEPROM that contains the module serial number, the vendor
Note
name and ID, a unique security code, and cyclic redundancy check (CRC). When an SFP module is
inserted in the switch, the switch software reads the EEPROM to check the serial number, vendor name,
and vendor ID and recomputes the security code and CRC. If the serial number, the vendor name or ID,
security code, or CRC is invalid, the switch places the interface in an error-disabled state.
If you are using a non-Cisco approved SFP module, remove the module from the switch, and replace it
Note
with a Cisco-approved module.
For more information about these SFP modules, see your SFP module documentation.
Catalyst 2950 Switch Hardware Installation Guide
1-12
Fiber-Optic SFP Module Port Cabling Specifications
Wavelength
(nanometers)
850
1300
1550
Core Size
Fiber Type (micron)
MMF 62.5
62.5
50
50
1
MMF 62.5
50
SMF 50
9/10
SMF 9/10
Chapter 1
Modal
Bandwidth
(MHz/km) Cable Distance
160 722 feet (220 m)
200 902 feet (275 m)
400 1640 feet (500 m)
500 1804 feet (550 m)
500 1804 feet (550 m)
400 1804 feet (550 m)
500 1804 feet (550 m)
— 32,810 feet (10 km)
— 43.4 to 62 miles (70
2
to 100 km)
Overview
OL-6156-01