Two-wire transmitters offer several major advantages over conventional four-wire types, which require two wires for the output signal and two more for the power supply, typically 120VAC. In applications where the process sensor may be located up to several thousand feet from the instrument being operated, two-wire transmitters are more advantageous because their current output signals do not attenuate or degrade over distance as do the voltage signals of typical four-wire conditioners. Additionally there can be significant savings in wiring cost since only two wires are needed for the power and signal when compared to the four-wire type.