TELEPHONE EXCHANGER

PURPOSE:To realize a conference call between >=3 subscribers, by connecting a conference trunk with a relay provided with a plurality of outgoing registers, in a telephone exchanger using a microcomputer for the maker. CONSTITUTION:Numbers of three subscribers belonging to the same group are registrated in a microcomputer 21 in advance, and when one subscriber of a group takes up a handset and depresses a number corresponding to a conference trunk 15 with a push button, a conference trunk 15 is confirmed for the group. Since the conference time is informed to all the members of the group, the three subscribers are connected to outgoing regsiters 8, 10 and 12 with a call of them, and relay contacts (not shown in the figure) provided for each register are driven with the computer 21, the lines for the three subscribers are connected to allow the conference through the trunk 15.