crossover cable is typically used to connect two hubs or switches. It can also be used
to test communications between two workstations directly, bypassing the hub.
The cable is used only in Ethernet UTP installations.
standard Ethernet UTP crossover cable used in both situations has its transmit
and receive wire pairs crossed so that the transmit set on one side is connected
to the receive set on the other. In the following figure four of the wires are
crossed pin 2 & 3 connect to pin 4 & 6 and pin 4 & 6 connect to pin
2 & 3.
Ethernet 10Base-T crossover cable
Sometimes, when you
try to troubleshoot a computer, you may need to connect to it without the help
of a Hub or a Switch. Then, you can not hook a diagnostic equipment like a
signal analyzer directly using a straight cable. You need a crossover cable to
A hardware loopback is a special connector for the Ethernet 10Base-T NICs. It is
used by the NIC’s software diagnostics to test transmission and reception
loopback and its connections
manufacturers provide diagnostic routines that could be used to troubleshoot
NICs for proper functioning. Such diagnostic routes normally use hardware
loopbacks through which an NIC transmits, and receives the same data for further
Generator and Tone Locator:
The combination of tone generator and tone locator is used in
telephone systems to locate cables.
The tone generator is a small
electronic device that sends an electrical signal down one set of UTP wires. The
tone locator is another device that is designed to emit a tone when it detects
the signal in a particular set of wires. When a cable is needed to be traced,
hook the generator to the copper ends of the wire pair to be found. Then move
the locator over multiple sets of cables until a tone is heared.