Conferencing system for distributed switching network

A conferencing device and method among terminals in a distributed digital telephone switching system is provided. The telephone switching system has a plurality of switching elements for interconnecting telephone units and telephone lines via communication links. A duplex path is set between each party in the conference and a designated bridge port. The speech from all the parties in the conference is summed and at the bridge port the sum is sent back to all engaged in the conference. As each party receives the sum, it subtracts its own speech data and therefore obtains the speech data from the other parties in the conference.