Solkor 7SR18 differential protection, E6 case size, 6 binary inputs, 8 binary outputs, 18 LEDs, measuring input: 4 CTs (1A/5A), 3 VTs (40-160 V), 24-250 V DC, 100 - 230 V AC, binary input threshold 19 V DC, signal: optical fibre link (1300 nm) (LC connection) 40 km, communication interface: USB front, RS485 rear, electrical ethernet RJ45 (x2) rear, IEC 60870-5-103 + Modbus RTU + DNP3 (user selectable) + IEC 61850 protection function packages: standard + 79 autoreclose