a data transmitting and receiving device and method are used for saving powers and maintaining the connection quality , stability and continuous link . the method includes the step of gradually adjusting the de - emphasis of the signal transmitted from the data transmitting and receiving device according to the setting value thereof . the method also includes the steps of transmitting training sequence signal with an amplitude and the default de - emphasis by the data transmitting and receiving device to the remote device , receiving the training sequence signal from the remote device , thereby the channel attenuation is estimated using the method , and a better de - emphasis is set up . then , the data transmitting and receiving device gradually increases the amplitude of the training sequence signal and re - transmits it until the remote device receives the training sequence signal transmitted therefrom .