Abstract: A method for making connections for conference calls in a PCM time division multiplex switching system incorporates the steps of adding, during each pulse frame, code words received from subscribers to each conference call, and storing code words representative of the intermediate sums resulting from such addition in a conference call memory. The code word representative of the total sum accumulated, for each conference call, during the preceding pulse frame is read out to each of the subscribers of each respective conference call, during his respective time slot, with the optional subtraction of the code word received from each subscriber before the total sum is transmitted to him. When subscribers to a conference call have consecutive time slots, the conference call memory is bypassed for the generation of the intermediate sum.