Using the example above of a flyback converter, customers can see the formation of a differential mode interference current on the supply lines. It can also be seen that the interference current is traveling in two different directions. For the differential signal, the current flows into the circuit (V1), through the load and back out (V2). The voltages on each wire are relative to ground potential. They do not travel through ground though. For systems that are cable based, users would be looking for this differential signal. This is the signal that will carry the data. For differential mode signals, the voltage on V1 minus V2 equals the Differential Voltage. Through a choke, this signal will create opposite, but equal, magnetic fields which will cancel each other out. The signal will pass through the choke un-attenuated as it sees a zero impedance created.