Abstract: A dynamic band allocation system wherein the bands of a SD-I line 20 are divided into a sub-rate band used by sub-rate units and a bit multiplex band, the sub-rate band being used as an on-demand band where a trunk and a channel are selected dynamically for connection according to demand, the bit multiplex band being divided into a fixed connection band and a fixed allocation band wherein terminals having a small speed unit are bit multiplexed so that the sum of the signaling speed of the terminals is closest to the speed of the sub-rate unit, and when call is originated from the terminal, selecting only the trunk matching its signaling speed for connection, and further dividing the on-demand band into areas for voice and for data, wherein the ratio of the division of voice/data is changed according to the traffic from time to time.

Abstract: A multiplexing system for ISDN circuits. Multiplexers in the system include data terminals, voice interfaces having voice trunks, high speed digital circuits and ISDN circuits, together with a control channel interface which connects trunking circuits by controlling calls on the control channel. When an outgoing voice call originates, data information from data terminals voice is multiplexed with compressed information from a voice interface and transmitted to trunking circuits. When calls originate, the control channel controls calls and connects them with trunking circuits. When using ISDN circuits, after setting up a communication channel for the circuits, a CPU controls calls to multiplex ISDN circuits on the control channel. By this structure decreasing the multiplexing ratio due to voice multiplexing call control on ISDN circuits can be eliminated when linking multiplexers with communication channels having high speed digital circuits and ISDN circuits.

Abstract: A multiplexing system for ISDN circuits. Multiplexers in the system include data terminals, voice interfaces having voice trunks, high speed digital circuits and ISDN circuits, together with a control channel interface which connects trunking circuits by controlling calls on the control channel. When an outgoing voice call originates, data information from data terminals voice is multiplexed with compressed information from a voice interface and transmitted to trunking circuits. When calls originate, the control channel controls calls and connects them with trunking circuits. When using ISDN circuits, after setting up a communication channel for the circuits, a CPU controls calls to multiplex ISDN circuits on the control channel. By this structure decreasing the multiplexing ratio due to voice multiplexing call control on ISDN circuits can be eliminated when linking multiplexers with communication channels having high speed digital circuits and ISDN circuits.