This paper presents an overview of a new acoustic echo canceller (AEC) especially for voice over IP hands-free applications. It mainly involves estimation of pure delay resulting from both room echo and audio input/output buffers, cancellation of non-linear acoustic echo caused by loudspeaker distortion, and residual echo reduction robust against echo-path change. The experimental results show that the new AEC achieved more than 50 dB of undesired echo reduction for every smart-phone or tablet used for the evaluation. This indicates that the performance of the proposed AEC does not depend on the difference in acoustic characteristics of the individual device.