Cisco 2948G-GE-TX - Catalyst Gigabit Ethernet Switch Przewodnik Instalacji Pobierz pdf (Strona 109)

C-3

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

78-6286-05

Appendix C Differential Mode Delay

modes. This is in contrast to an unconditioned launch, which, in the worst case,

might concentrate all of its light in the center of the fiber-optic cable, exciting

only two or more modes equally.

A significant variation in the amount of DMD is produced from one MMF cable

to the next. No reasonable test can be performed to survey an installed cable plant

to assess the effect of DMD. Therefore, you must use a mode-conditioning patch

cord for all interfaces using MMF when the link span exceeds 984 feet (300

meters). For link spans less than this, you can omit the patch cord (there is no

problem using it on short links).

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Cisco 2948G-GE-TX - Catalyst Gigabit Ethernet Switch Przewodnik Instalacji Strona 109