The HGLN-CAT5J24 is a compact indoor lightning surge arrestor which provides protection for CAT5 data applications. The unit is fully compatible with 10/100 Base-T Ethernet networks, providing protection to both Ethernet data pairs as well as the PoE DC power feed. The unit supports both PoE modes A and B for of supplying DC power. Power can be fed up the CAT5 data pairs, 1-2, 3-6 or using the two unused pairs, 4-5, 7-8.

High-speed semiconductors clamp any voltage, positive or negative on the wires. The limits are +/- 36 volts on the four cable pairs. The unit is compatible with both normal and inverted polarity voltage PoE equipment. The design utilizes Thyristor diode technology which has superior power handling capability compared to TVS or Zener diode based designs.