To provide a high-voltage separation communication device that is compact, has low power consumption, transmits data at a relatively high data transfer speed, and has high-voltage resistant capability.

High-voltage separation and high-voltage insulation breakdown performance characteristics are provided in a small package. A coil transducer 20 transmitting and receiving a data signal or a power signal over the coil transducer is provided by a primary coil 50 and a secondary coil 60 via the coil transducer without causing any high-voltage breakdown between the primary and secondary coils 50, 60 disposed on both sides of the coil transducer 20. A center core layer separates a transmission oil from a reception coil, and does not include any vias disposed through the center core layer. At least one portion of the coil transducer 20 is formed from an electrically insulated non-metallic, non-semiconductor material with low dielectric loss.