The ADAM 6521 is a rugged 10/100Base-T Ethernet switch that accepts any voltage between 10 and 39 Vdc with surge protection up to 3,000 Vdc. They are suitable for any dc environment. The switch lets users interconnect four copper and one fiber-optic network. It automatically senses 10 or 100 Mbps and provides full- and half-duplex flow control. The RJ45 port connect to any 10/100Base-T Ethernet network.