invention as shown echo canceller 300 includes double talk detector 310 high pass filter 315 adaptive filter 320 fixed and variable delay estimator 340 error estimator or subtractor 318 and nonlinear processor 330 during its operation echo canceller 300 receives rin signal 334 from the far end which is fed to double talk detector 310 adaptive filter 320 and fixed and variable delay estimator 340 and then rin signal 334 is passed through as rout signal 304 to slic 235 and pbx 220 including slic 225 as discussed above ip pbx hybrid echo 237 and pbx hybrid echo 227 cause rout signal 304 to be reflected as part of sin signal 302 from the near end which is fed to high pass filter 315 and an output of high pass filter 315 is fed to double talk detector 310 high pass filter 315 which is placed at the transmitting side of echo canceller 300 removes dc component from sin signal 302 double talk detector 310 controls the behavior of adaptive filter 320 by providing double talk indication 311 during periods when sin signal 302 from the near end reaches a certain level because echo canceller 300 is utilized to cancel an echo of rin signal 334 presence of speech signal from the near end would cause adaptive filter.