Conference call provisions are incorporated in a Time Division Multiplex (TDM) signalling exchange wherein the signals are summed energywise and transmitted to a receiving subscriber set without subtracting the signal from that subscriber set and any tendency toward regeneration is obviated by filtered signal reconstruction in conjunction with sample-and-hold signal reconstruction of the TDM signalling system. Simple low-pass, high-pass and band-shaping filters are adequate for the purpose.
展开▼
