❑There is an equivalent fiber distance for the 10BASE-T Modules (see Rule 4). The equivalence is:
–420 meters for signals that externally enter a 10BASE-T Module port
–165 meters for signals that internally enter a 10BASE-T Module via the ONline Concentrator backplane
Thus, for every pair of 10BASE-T Modules that a signal goes through, there is a fiber equivalent distance of 585 meters (420 m + 165 m = 585 m). This is also true if a signal makes a roundtrip through a single 10BASE-T Module, i.e., enters a 10BASE-T port externally and exits through another port on the same 10BASE-T Module. This counts as 585 meters of fiber equivalent distance, and as a full repeater.
Fiber Backbone, Twisted Pair To-The-Desk Example
In the sample configuration shown in Figure 2-1, we determine if the transceivers are within legal Ethernet limits. This example is applicable to both unshielded and shielded twisted pair cables. Note that 22 gauge unshielded twisted pair cable is used to connect 10BASE-T Transceivers to the 10BASE-T Modules in the concentrators.
The first step is to identify the two transceivers that are likely to be the greatest fiber equivalent distance apart. In this case, they are 10BASE-T Transceivers A and B.
2 - 8 ONline Ethernet 10BASE-T Module User’s Guide