The AL-CAT5W-4-24 is a multi-port indoor and outdoor lightning surge arrestor, which provides protection for CAT5 data applications. A single unit protects up to four separate CAT5 lines. This model is fully compatible with industry-standard 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 design utilizes Thyristor diode technology, which has superior power handling capability compared to TVS or Zener diode based designs. The unit is compatible with both normal and inverted polarity voltage PoE equipment.