A loopback plug is a device used to test ports (such as serial, parallel USB and network ports) to identify network and network interface card (NIC) issues. Loopback plug equipment facilitates the testing of simple networking issues and is available at very low costs.
Then, what is a cable tester used for?
A cable tester is a device that is used to test the strength and connectivity of a particular type of cable or other wired assemblies. There are a number of different types of cable testers, each able to test a specific type of cable or wire (some may be able to test different types of cables or wires).
What is a crimping tool used for?
A crimping tool is a device used to conjoin two pieces of metal by deforming one or both of them in a way that causes them to hold each other. The result of the tool's work is called a crimp. A good example of crimping is the process of affixing a connector to the end of a cable.
What is the use of LAN card?
Most laptops today have integrated LAN cards both for wired and wireless networking. A PCI card goes inside of a PC computer. The card shows an Ethernet port, which is the spot where you plug in a network cable. The LAN card you select often determines the protocols that are used on the network.