3Com 5112M-TPLS installation and operation guide Twisted Pair Backbone, Twisted Pair To-The-Desk

Do not exceed the distances as defined in Table 2-2 for the link from a Security Module to a 10BASE-T Transceiver.

Table 2-3. Maximum Link Distance on Twisted Pair

Cable Gauge	Supports Link Distances Up To:
Unshielded Twisted Pair:	Normal Squelch
10BASE-T
22 (.6 mm)	100 m
24 (.5 mm)	100 m

Twisted Pair Backbone, Twisted Pair To-The-Desk

In constructing a twisted pair backbone, one additional configuration rule must be considered. Ensure there are no more than eight Security Modules in the path between any two transceivers due to Ethernet's four-repeater rule. This is because each Security Module counts as a 1/2 repeater unless the signal goes in one port and out another port of the same module, in which case the module counts as a full repeater.

If you have more than eight Security Modules serially connected, add a bridge. Each bridge creates a subnetwork. Each subnetwork can have its own 420 meter network diameter.

The configuration in Figure 2-2 illustrates a possible unshielded twisted pair network using 22 gauge cable.

2 - 10 ONline 10BASE-T Security Module Installation and Operation Guide