3Com 5104M-FL1 Determining Maximum 10BASE-FL Link Distances, Calculating Maximum Link Distance

Determining Maximum 10BASE-FL Link Distances

This section describes how to calculate the maximum allowable link distances between two 10BASE-FL ports.

To do this, you must know the following information:

❑10BASE-FL Module optical (link) power budget

❑Fiber cable diameter (for example, 50 micron, 62.5 micron)

❑Fiber cable light loss/km (for example, 3 dB loss/km)

❑Number of patch panel connections between ports

❑Number of splices on the link

The following tables assist you in obtaining this information:

❑Table 2-3 - Outlines the optical power budget for the 10BASE-FL Module.

❑Table 2-4 - Lists typical losses for various connector types.

❑Table 2-5 - Lists typical losses for various fiber cables.

Calculating Maximum Link Distance

To calculate the maximum link distance allowed:

1.Determine the optical power budget for the 10BASE-FL port (Table 2-3).

2.Subtract the optical power loss due to patch panels and splices (Table 2-4) from the optical power budget for the 10BASE-FL port.

3.Subtract the dB loss/km rating of the fiber cable (Table 2-5) from the remainder of Step 2. If the result is greater than 0 dbm, the link distance is valid.

2 - 6 ONline Ethernet 10BASE-FL Installation and Operation Guide