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Model FS102, Model FS104, Model FS108 Fast Ethernt Switch Installation Guide
Twisted Pair Cables
For two devices to communicate, the transmitter of each device must be connected to the receiver
of the other device. The crossover function is usually implemented internally as part of the
circuitry in the device. Most ports on switches and repeaters have media-dependent interfaces with
crossover ports. These ports are referred to as MDI-X or normal ports. Computer and workstation
adapter cards are usually media-dependent interface ports referred to as MDI or uplink ports.
The figures illustrate the use of straight-through and crossover twisted pair cables.
Yellow Rx/Tx
Collision LED is
blinking
excessively.
Data collision is
occurring on the port.
The port and switch might be functioning correctly.
However, check the following to make sure that
excessive collisions are normal (as in most Ethernet
networks) and not caused by:
• Incorrect cabling or connectors
• Wiring techniques
• Mismatched duplex operating mode settings
Green FDX LED is
off when you have
set the port to
operate in full-
duplex mode.
Port is operating in
half-duplex mode.
Make sure the connected device is able to operate at
half-duplex mode and check the specifications of the
connected device to make sure it has the ability to
signal the operating mode. Verify that the connected
device is operational. If the connected device is an
adapter card, make sure you have an adapter card
that is capable of 100 Mbps operation and set to 100
Mbps if it is not autosensing.
Symptom Cause Solution
Cable and Connector Information
Straight-through
twisted pair cable
Crossover
twisted pair cable
8146EB
Tx
Uplink or
MDI port
Normal or
MDI-X port
Normal or
MDI-X port
Normal or
MDI-X port
Rx
1
2
3
6
Tx
Rx
1
2
3
6
1
2
3
6
1
2
3
6
Tx
Rx
Tx
Rx