Editing Digital current loop interface (section)

==Signaling conventions==
A digital current loop uses the absence of current for high (space or break), and the presence of current in the loop for low (mark).<ref name=PARR98/> This is done to ensure that on normal conditions there is always current flowing and in the event of a line being cut the flow stops indefinitely, immediately raising the alarm of the event usually as the heavy noise of the teleprinter not being synchronized, something that would not have been possible if the idle state  had been no current flowing.