When a LAN connection fails, you can swap out the cable to see if it is the problem or you can reach for the Monoprice™ LAN Quicker 009!This cable tester is designed to troubleshoot RJ45 LAN cables, both UTP and STP. It not only tells you if the cable passes or fails the test, it indicates which pins fail and whether they are open, shorted, or crossed. This allows you to easily see if the cable is your problem and what you need to do to fix it, if it is.The tester has two basic testing modes: Auto and Step.In auto mode it makes a single pass over the cable and gives a result. It shows whether the cable passed or failed and, if it failed, the type of failure (open, short, or cross) and the affected pins/wires.In step mode the tester steps through each wire independently with each press of the Test button. This allows you to get detailed results for a cable that may have multiple types of failures. For example, you can see that pin 1 is open, pins 2 and 3 are crossed, and that pin 4 is shorted.WARNING!!! Do not test live circuits as it could cause damage to the tester unit or personal injury.Note: This product has a universal card packaging that is used for PIDs 8129, 8130, and 8131, with the individual model marked on the back. The front of the packaging includes functionality tags for all three testers combined. Therefore, the packaging erroneously indicates that this tester is capable of testing HDMI, Coax, and RJ12 cables, which it is not designed to do. Also note that the manual for this tester shows test results for RJ12, Coax, and USB cables. While it is electrically capable testing these types of cables, the necessary connectors or adapters are not included with the tester. Support Files: User's Manual (Jul 21, 2011)Monoprice™ and all Monoprice logos are trademarks of Monoprice Inc. Updated Jan 20, 2022 Warning: This product may contain a chemical known to the State of California to cause cancer, birth defects.