Gigabit Ethernet Optical Specifications; Patch Cord - Cisco 7603 - Modular Expansion Base Installation Manual

Chapter 2 Preparing for Installation

Gigabit Ethernet Optical Specifications

Table 2-6
Ethernet switching modules, and the Gigabit Ethernet uplink ports on the supervisor engines. All Gigabit
Interface Converter (GBIC) interfaces have SC connectors, and the minimum cable distance for all
GBICs listed (MMF and SMF) is 6.5 feet (2 meters).
Table 2-6 Gigabit Ethernet Maximum Transmission Distances
Wavelength
GBIC (nm)
3
SX 850
LX/LH 1300
5
ZX 1550
1. The number given refers to the core diameter. The cladding diameter is usually 25 microns.
2. Distances are based on fiber loss.
3. MMF only.
4. Patch cord required.
5. You can have a maximum of 24 1000BASE-ZX GBICs per system to comply with FCC Class A regulations.
6. Dispersion-shifted single-mode fiber-optic cable.
7. The minimum link distance for ZX GBICs is 6.2 miles (10 km) with an 8-dB attenuator installed at each end of the link.
Without attenuators, the minimum link distance is 24.9 miles (40 km).

Patch Cord

When using the long wavelength/long haul (LX/LH) GBIC with 62.5-micron diameter 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).
We do not recommend using the LX/LH GBIC and MMF without a patch cord for very short link
Note
distances (10 to 100 meters). The result could be an elevated bit error rate (BER).
The patch cord is required to comply with IEEE standards. IEEE found that link distances could not be
Note
met 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 the output of the patch cord, the LX/LH GBIC complies with the IEEE 802.3z standard for
1000BASE-LX. For a detailed description of this problem, see the
page
OL-5077-7
provides cabling specifications for the 1000BASE-X interfaces, including the OSMs, Gigabit
Fiber Type Core Size
(MHz km) (micron)
MMF 62
62
50
50
4
MMF 62
50
50
SMF (LX/LH) 9/10
6
SMF 9/10
8
2-14.
1
Modal Bandwidth
(MHz km) Cable Distance
160 722 ft (220 m)
200 902 ft (275 m)
400 1640 ft (500 m)
500 1804 ft (550 m)
500 1804 ft (550 m)
400 1804 ft (550 m)
500 1804 ft (550 m)
– 6.2 mi (10 km)
– 43.5 mi (70 km)
– 62.1 mi (100 km)
Determining Cable Distances
2
7
"Differential Mode Delay" section on
Book Title
2-13