The old 10-50 mA standard lost the battle to 4-20 mA due to the following benefits: 1) The same two-wires carry both the sensor power and signal, 2) 4-20 mA is easily converted to a 1-5 VDC input via a 250 Ohm, _ Watt resistor or 1-10 VDC input via a 500 Ohm, _ Watt resistor, 3) 4-20 mA is low current and therefore has a low heating loss through the signal wire, and 4) with shielded cable, 4-20 mA is noise resistant to radiated and inducted interference.