A magnetic interface circuit for interfacing between a cable side and a circuit side of a networking communication channel. The magnetic interface circuit includes a transformer and a 3-wire common mode choke (CMC). The transformer has a first winding connected to the cable side of the channel and a second winding connected to the circuit side of the channel. Each of the first and second windings has two output ports. The 3-wire CMC has a center winding and two outer windings respectively connected to the output ports of the first or second winding. The center winding has two opposite ends both used for connecting to ground.