an echo canceler - suppressor speakerphone arrangement effectively addresses the limitations of regeneration and reverberant return echo inherent in the design of speakerphones . the tendency for regeneration is eliminated by employing adaptive echo cancellation in the receive path of the speakerphone arrangement to cancel speakerphone talker echo across a hybrid and thereby reduce the local loop gain to below unity . and the generation of a reverberant return echo to the far - end party is avoided by employing adaptive echo suppression in the transmit path of the speakerphone arrangement . near - full and full duplex operation are regularly achieved since the receive path remains open at all times and the transmit path has its gain reduced only to the level necessary to suppress excessive reverberant return echo .