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Network Installation Section 2-4
• Do not lay the twisted-pair cable near devices that generate noise.
• Do not lay the twisted-pair cable in locations subject to high temperatures
or high humidity.
• Do not lay the twisted-pair cable in locations subject to excessive dirt and
dust or to oil mist or other contaminants.
Hub Installation
Environment Precautions
• Do not install the hub near devices that generate noise.
• Do not install the hub in locations subject to high temperatures or high
humidity.
• Do not install the hub in locations subject to excessive dirt and dust or to
oil mist or other contaminants.
Hub Connection Methods If more hub ports are required, they can be added by connecting more than
one hub. There are two possible connection methods for hubs: Cascade and
stacked.
Cascade Connections
• Connect two hubs to each other as follows: Connect an MDI port to an
MDI-X port with a straight cable; connect two MDI ports with a cross
cable; and connect two MDI-X ports with a cross cable.
Note It is very difficult to distinguish cross cables and straight cables by appear-
ance. Incorrect cables will cause communications to fail. We recommend
using cascade connections with straight cables whenever possible.
• With cascade connections, up to 5 segments can be connected using up
to 4 repeaters (i.e., 4 hubs).
Stack Connections • Connect the hubs using special cables or special racks.
• Normally there is no limit to the number of hubs in a stack, and each stack
is treated as one hub. Some hubs, however, are limited in the number of
hubs per stack.
MDI-X port
(cross)
Hub
Hub
Hub
Straight cable
Cross cable
Hub
MDI ports
Hub
Four stackable hubs
Stack cable
Two stackable hubs
Stack cable
