IEC 61850-3 modular managed rackmount Ethernet switch system with 3 slots for Fast Ethernet modules, 1 slot for a Gigabit Ethernet module, or 4 slots for Fast Ethernet modules, for a total of up to 24+4G ports, cabling on rear panel, 2 isolated power supplies (88-300 VDC or 85-264 VAC), -40 to 85°C operating temperature