Sim-Ex™ Tutorial for Network+

4.0 Network Support

  1. Troubleshooting scenario
  2. The Troubleshooter's Resources
  3. Manufacturers Troubleshooting Resources
  4. Hardware Network Troubleshooting Tools
  5. Software Troubleshooting Tools

4.4 Hardware Network Troubleshooting Tools:

The four most popular hardware tools are:

  • A crossover cable
  • A hardware loopback
  • A tone generator
  • A tone locator

The Crossover cable: The 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.

The 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.

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Standard 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 connect directly.

The Hardware Loopback: 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 capabilities.

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Hardware loopback and its connections

The NIC 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 diagnsis.

Tone 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.

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