Accton Technology 12mi SNMP, 12i manual Calculating the Power Budget for Fiber Optics

Fast EtherHub 3500 System User’s Guide

connect one end of the cable to the MDI port on the extender module, and the other end to the MDI-X port on the target device (or vice versa). When inserting an RJ-45 plug, be sure the tab on the plug clicks into position to ensure that it is properly seated. Note that as a general rule, the length of any twisted-pair cable should not exceed 100 meters.

Connecting Fiber Optic Cabling - For the 100BASE-FX module,

prepare fiber optic cable with SC or ST connectors at both ends. When connecting the module directly to an end-node device (e.g., workstation or file server), run cable from the Rx (Tx) port on the module to the Tx (Rx) port on the target device. Also, when daisy-chaining SmartExtender Modules, make similar connections between the current module and the next device in the stack. When inserting a cable, be sure the tab on the plug clicks into position, to ensure that it is properly seated. Note that as a general rule, the length of fiber optic cable should not exceed 2 kilometers. However, power budgeting must be considered when calculating the maximum cable length for your specific environment (as described later in this chapter).

Distance Limit and Power Loss in Fiber Optics - When using fiber

optic cabling, the maximum length between two hubs can be up to 2 kilometers. However, you must consider power loss when calculating the actual length of cable that can be used with your system. You can calculate power loss with the following formula:

m = (p dB - i dB) c dB/km

Variable

m

pdB i dB

c dB/km

Description

cable length (kilometers) power budget intervening devices

(e.g., patch cables and splices) loss per kilometer of cable

Table 2.1 Calculating the Power Budget for Fiber Optics

2-8 Installing the System