Abstract: The invention supposes the use of an integrated services digital network (102) which has a function of communicating the number of a source communications terminal (101) as source number information. A source number information identifying section (104) in a central unit 103 identifies source number information from the integrated services digital network (102). Communications processing sections (105) in the central unit (103) process arriving channels for which source number information is recognized as being identical, as arriving channels from the same communications terminal. As a result, the central unit (103) identifies arriving channels from a plurality of communications terminals (101) individually and then processes them without communicating source number information with the communications terminals.

Abstract: A system generating composed signals of stable multiple pictures reduces a scale of hardware required for forming video signals sent from a plurality of terminals into one composed picture on a video conference system. A system generating composed signals of multiple pictures for use in a video conference system includes video conference terminals connected via a network, a multi-point control unit connected to the network for controlling transmission of video signals among the video conference terminals, and a multiple picture composer connected to the multi-point control unit for receiving video signals sent out from the video conference terminals through the multi-point control unit, and information showing a reducing ratio and display positions of the video signals.

Abstract: A multipoint multichannel connection device for line-connecting communication terminals at multiple points and a central unit through an integrated services digital network which has a function of communicating the number of a source communications terminal as source number information includes a source number information identifying section incorporated in a central unit, which identifies source number information from the integrated services digital network unit process arriving channels for which source number information is recognized as being identical, as arriving channels from the same communications terminal. As a result, the central unit identifies arriving channels from a plurality of communications terminals individually and then processes them without communicating source number information with the communications terminals.

Abstract: A packet data communication system with a ring-type transmission line circulates a predetermined number of slots in which packets to be transmitted are loaded. The system includes interface nodes, provided on the ring-type transmission line, for loading packets on slots and receiving packets from slots for terminals connected thereto. In each interface node, there are a predetermined number of sub-transmission lines, for passing each of slots in parallel through the interface node, terminal interfaces each having a plurality of sending buffers for storing packets and a plurality of receiving buffers for storing packets, and a switch for connecting each of the sending buffers and receiving buffers to any one of the sub-transmission lines.