3com 5108M-TP User Manual

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2 - 4 ONline Ethernet 10BASE-T Module User’s Guide
4
Certain LAN devices 
on the network shrink 
the maximum Fiber 
Ethernet network 
diameter to less than 
4200 meters.
Many LAN products delay the signal 
that goes through them. This is 
known as equivalent distance. Every 
microsecond delay reduces the 
maximum link distance. In fact, 
every microsecond delay shrinks the 
network diameter by approximately 
200 meters of fiber cable. Table 2-2 
lists the Equivalent Distances for 
other 3Com products.
5
Assume that one 
meter of coaxial or 
twisted pair is equal to 
one meter of fiber 
cable. 
This is a conservative rule of thumb. 
For example, the actual equivalence 
is about 1.1 meters of coaxial for 
every meter of fiber. For simplicity, 
assume one meter.
Table 2-1.  Seven Basic Network Rules (Continued)
Rule
Definition
Recommendations/Notes