foerfarande foer konvergering av i ekoslaeckare i boerjan av that samtal

摘要

Converging of an echo canceller (4A-D) integrated into a telephone exchange (1, 2) is initiated at the start of a telephone call by an internal command of the telephone exchange given by a call control (2) of the telephone exchange as soon as the call control (2) has observed an off-hook state of a called subscriber connection. The command causes the echo canceller (4A-D) to transmit a test signal to the echo path for converging the echo canceller before appearance of the speech signal.