When connected to an Ethernet cable, a network cable tester tells if the cable is capable of carrying an Ethernet signal. If the cable carries the signal, this indicates that all the circuits are closed, meaning that electric current can move unimpeded through the wires, and that there are no short circuits, or unwanted connections, in the wire. Network cable testers vary in complexity and price, but a basic tester consists of a source of electrical current, a measuring device that shows if the cable is good, and a connection between the two, usually the cable itself. Computer networks use Ethernet cables to allow computers in the network to “talk” to each other. An Ethernet cable has eight wires that are arranged in four pairs. For current to flow correctly, the wire pairs must be connected in the proper order. A network cable tester can identify if the wires are paired correctly. It can also show if there is a break in the insulation, a situation which allows crosstalk between two wires that should not be connected. The tester can also tell whether the cable has the proper level of resistance. If a network isn’t working correctly, the problem is frequently user error or other problems. It will rarely be a faulty cable. A network cable tester is more frequently used to tell whether a patch cable will work before it is connected. The cabling should first be examined visually to identify any obvious problems. If everything looks correct, a network cable testing device may then be used. A network cable tester can be a simple apparatus that merely identifies whether current flows through the cable, or it may be a professional-level, complex device that gives additional information that helps identify the problem. Professional-level network cable testers may not only tell if an open circuit exists, but may identify where the break is located. Some also identify the gauge of wire used and can generate their own signal to test for interference. Basic network cable testers can test for simple connectivity issues but may not identify other problems that cause the cable to malfunction. Cabling may not work when it is near a source of interference or if the cable is too long. Intermittent faults may develop that do not show up when the cable is tested. Sometimes the problem is not sustained long enough to show up on the tester.
20th Jan 2015