Leading you to an educated decision.
A current loop describes two different electrical signaling schemes. For digital serial communications current loop is a communication interface that uses current instead of voltage for signaling. Current loops can be used over moderately long distances (tens of kilometres), and can be interfaced with optically isolated links. Analog current loops are used where a device must be monitored or controlled remotely over a pair of conductors. Only one current level can be present at any time.