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 2 km 2-port 100Base-FX interface on ISW-621TS15 for up to 15 km Complies with IEEE 802.3, IEEE 802.3u 10/100Base-TX, 100Base-FX Ethernet standard Supports auto negotiation and 10/100 Mbps half / full duplex mode for each copper port Backplane (Switching Fabric): 1.2 Gbps IP30 metal case / protection