Lopatester Video: Photos: To make you own DIY ethernet cable tester you need PCB RJ45 connector (2pcs per tester) store 1 store 2 CR2032 battery holder (2pcs per tester) store 1 store 2 LEDs (8 pcs per tester) store 1 store 2 Two CR2032 batteries per tester (you can buy it at local store)