Network Cable Tester for $0.99. Shipping is $5.02 for a total of $6.01 shipped. Here is a screenshot for your reference. This network cable tester can determine wrong connections, short circuits and open circuits, which potentially can save a lot of trouble when running network cables. It works for the most common cable types, including RJ11, RJ12, and RJ45. Note that it may take a while to receive your order.