This paper presents a high data rate, non-contact interface using a coupled transmission line (CTL) composed of two differential transmission lines. The proposed CTL can achieve a measured loss of -13.4 dB and a 3-db bandwidth of 3.4-9.0 GHz as a non-contact channel for a 1-mm communication distance. This wideband characteristic makes it possible to achieve high-speed communication using a single channel. The hysteresis buffer-based receiver recovers the transmitted data from the distorted waveforms derived from the AC coupling characteristics of the channel. The interference from the power delivery coil to the CTL is also evaluated. The simulated results showed that the interference was less than -57.8 dB at 13.56 MHz. The system could achieve a communication speed of 12 Gb/s with a BER <; 10-12 at a communication distance of 1 mm both with and without a wireless power supply of 75 mArms. The timing margin with the wireless power supply was 41 ps (=0.49 UI).