<P> Neither of the tip and ring conductors is permanently connected to earth ground , but may be connected to ground during signaling operations . Typically , the ring conductor has a direct current ( DC ) potential of − 48 V to − 52 V with respect to the tip conductor when the line is in the on - hook ( idle ) state . Floating both conductors , not referencing either one to ground , minimizes the pickup of hum from any nearby alternating current ( AC ) power wires . </P>
what is the idle line voltage in australia
a direct current ( DC ) potential of − 48 V to − 52 V with respect to the tip conductor