tony........futaba is talking about electo-magnetic fields produced by the current flowing in the wires themselves... since the current flowing in red and black leads is opposte to each other ,then the magnetic fields are also opposite and therefore cancell each other. thats their theory.......... when a external electro-magnetic field passes across twisted pairs it induces equal currents in each wire. if the first amplifier in the device (that the wires go to) has some form of common mode rejection, the interference is rejected. this is EE 401