There are 2 rows of 9 LED's corresponding to each of the possible connector pins of the AudioJog Pro 8 – Cat 5e Network Cable Testers and one for the screen (or ground) connection. As each pin is activated, the LED's indicate all connections associated with that pin, so that short, open and crossed circuits can be easily found. The LED's also show the possibility of high resistance or leakage connections. 2 LED's indicate a good digital network connection, either Straight through, or Crossed over.