Method of and system for switching of conference circuit

A conference call in a digital telephone switching system is provided with a first code converter (CCL), the encoded into linearly coded speech samples converts non-linear, with an adder (ADD), the sums originating from the participants of the conference, converted speech samples, and with a second code converter (LCC), which converts the sum values ​​back into non-linearly coded speech samples. To avoid distortions without the insertion loss increase, the speech samples of each participant in an evaluation circuit (EVC) are integrated over time and compared. The voice samples of the loudest participant are undamped the adder fed while all other participants before the Ad dieren be attenuated by a predetermined value.