The MSM7617 cancels echoes (acoustic or line echoes) generated in voice channels. It is a lowpower CMOS LSI device with two channels. MSM7617 echo canceling is performed by digital signal processing. It negates echoes by estimating the echo channel and then generating a pseudo-echo signal. When used as an acoustic echo canceler, the MSM7617 can cancel acoustic echoes between speaker and microphone that occur during hands-free speaking with car phones, conferencing system phones, etc. When used as a line echo canceler, the MSM7617 can cancel line echoes returned by hybrid impedance mismatches. By setting its mode for use as a single cross-connected channel, the MSM7617 can cancel both acoustic and line echoes.