Generally, the testing is done in two phases. If a connection 'goes to the wrong place' it is said to be 'miswired' (the connection has two faults: it is open to the correct contact and shorted to an incorrect contact). When an unintended connection exists it is said to be a 'short' (a short circuit). When an intended connection is missing it is said to be 'open'. Both portions of such a tester will have connectors compatible with the application, for example, modular connectors for Ethernet local area network cables.Ī cable tester is used to verify that all of the intended connections exist and that there are no unintended connections in the cable being tested. A cable tester may be connected to both ends of the cable at once, or the indication and current source portions may be separated to allow injection of a test current at one end of a cable and detection of the results at the distant end.
A cable tester may also have a microcontroller and a display to automate the testing process and show the testing results, especially for multiple-conductor cables. Generally a basic cable tester is a battery operated portable instrument with a source of electric current, one or more voltage indicators, and possibly a switching or scanning arrangement to check each of several conductors sequentially.
