Plug the master into one cat5,cat5e, or cat6 jack and plug the slave into another jack. The LEDs will light in a sequence, traveling in a line, if the wiring is correct. If any LED doesn"t light, lights red instead of green, or the sequence is wrong, then there is a wiring error. The problem will be identified by the manner the LEDs failed to display properly. Features: * LAN tester with remote * Check in loopback or installed/remote mode * Works with CAT5 installations * RJ45 and BNC capability * Tests shielded and unshielded twisted pair cable (STP/UTP) * Auto scanning * Includes a dongle for testing coax cables * Uses a 9V battery (not included) What"s In the Box: * Eclipse 400-001 Multi-Network Cable Tester with Remote