4-port 10/100Base-TX RJ-45 with auto MDI/MDI-X function for ISW-621T series. 2-port 100Base-FX interface on ISW-621T for up to 2km (multi-mode fiber 62.5/125µm, 50/125µm) transmission distance. IP30 metal case / protection. DIN rail and wall mount design. 12 to 48V DC, redundant power with polarity reverse protection and connective removable terminal block for master and slave power. Supports EFT protection 6KV DC for power line. Supports 6KV DC Ethernet ESD protection. -40 to 75º C wide operating temperature. WITH LAYER 2 FEATURES.