2 - 24 ONline Ethernet 10BASE-FL Installation and O peration Guide
Therefore, for each pair of ONline Fiber Modules that a signal passes
through, there is a fiber equivalent distance of 190 meters (140 m +
50 m = 190 m). In addition, a signal m aking a round trip through the
module (that is, entering a port externally and exiting through
another port on the same module) counts as 190 meters of fiber
equivalent distance.
2. Do not count the ONline Ethernet Fiber Module and the ONline
Ethernet Port-Switching Fiber Module as repeaters when determining
the maximum number of repeaters in your network. These are
repeater-less devices.
Example: Fiber Backbone, 10BASE-FL to-the-Desk
Use the following example to determine if the 10BASE-FL transceivers are
within legal Ethernet limits. First identify the two transceivers that are likely
to be the greatest distance apart in Figure 2-8. In this case, they are
10BASE-FL transceivers A and B
.
Figure 2-8. Sample Fiber Backbone, 10BASE-FL to-the-Desk
Configuration
75 m
1000 m
500 m
4200 m
Maximum
Diameter
Fiber 50 m+190 m+140 m
Modules = 380 m
Cable Distance
1.
3.
4.
B
Concentrator A
Concentrator B
Concentrator C
FL2.
Equivalent Distance
Modules = 560 m
Equivalent Distance
C
2025 m
10BASE-FL
A
450 m
50 m
Fiber Module
(450 m + 1000 m +
500 m + 75 m)
Fiber Module
10BASE-FL
10BASE-FL
10BASE-FL Module
10BASE-FL Module
330 m + 230 m
Remaining
Distance 1235 m