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DI-624M User’s Manual
D-Link Systems, Inc.
Frequently Asked Questions
What´s the difference between a crossover cable and a straight-through cable?
The wiring in crossover and straight-through cables are different. The two types of cable
have different purposes for different LAN configurations. EIA/TIA 568A/568B define the
wiring standards and allow for two different wiring color codes as illustrated in the
following diagram.
*The wires with colored backgrounds may have white stripes and may be denoted that
way in diagrams found elsewhere.
How to tell straight-through cable from a crossover cable:
The main way to tell the difference between the two cable types is to compare the
wiring order on the ends of the cable. If the wiring is the same on both sides, it is straight-
through cable. If one side has opposite wiring, it is a crossover cable.
All you need to remember to properly configure the cables is the pinout order of the two
cable ends and the following rules:
A straight-through cable has identical ends. A crossover cable has different ends.
It makes no functional difference which standard you follow for straight-through cable
ends, as long as both ends are the same. You can start a crossover cable with either
standard as long as the other end is the other standard. It makes no functional difference
which end is which. The order in which you pin the cable is important. Using a pattern
other than what is specified in the above diagram could cause connection problems.
When to use a crossover cable and when to use a straight-through cable:
Computer to Computer – Crossover
Computer to an normal port on a Hub/Switch – Straight-through
Computer to an uplink port on a Hub/Switch - Crossover
Hub/Switch uplink port to another Hub/Switch uplink port – Crossover
Hub/Switch uplink port to another Hub/Switch normal port - Straight-through
