3Com 5108M-TP Switch User Manual


 
Designing and Expanding the Network 2 - 11
Twisted Pair Backbone, Twisted Pair To-The-Desk
In constructing a twisted pair backbone, one additional configuration rule
must be considered:
There can be no more than eight 10BASE-T Modules in the path
between any two transceivers due to the Ethernet four-repeater
rule (each 10BASE-T Module counts as a 1/2 repeater). You must
add a bridge if you have more than eight 10BASE-T Modules
serially connected.
The configuration in Figure 2-2 illustrates a possible unshielded twisted pair
network using 22 gauge cable.
Figure 2-2. Unshielded Twisted Pair Network
Note that when connecting two concentrators with twisted pair cable, use
port 8 on one of the 10BASE-T Modules and disable crossover mode for
that port. This allows a direct connection to another 10BASE-T Module
without the need for an intervening adapter. (Refer to Dip Switch SW3
(Crossover Mode, Channel Select, Squelch) in Chapter 1 for information on
crossover mode and the crossover mode switch setting.)