To provide a method for compensating and/or reducing an echo and/or noise in a TC system in order to transmit a useful acoustic signal, especially a human voice.

The method of this invention comprises a step (a) where a uniform reference is defined for the quality of the characteristics of a communication terminal including optional echo compensation and/or echo reduction capability with respect to production of an echo and/or a noise signal, a step (b) where a quality value corresponding to at least one communication terminal included in a communication connection is obtained, a step (c) where a reference additionally required is decided to compensate an echo and/or noise with respect to a prescribed residual value, and a step (d) where the decided reference is implemented by using a compensation unit in at least one exchange facility included in the communication connection.