Patent ID: 6563842
Filing Date: 2003-05-13
Classification: H04J,H04M,H04Q

Abstract:
A communications system comprising:subscriber-side transmission devices, each provided in a remote area, for converting analog signals from subscriber terminals divided into a plurality of groups to digital signals, time-division multiplexing the digital signals on a per-group basis to obtain time-division multiplex data having a first bit rate, further time-division multiplexing the time-division multiplexed data of each group to obtain time-division multiplexed data having a second bit rate, and sending the time-division multiplexed data having the second bit rate, a switch-side transmission device for demultiplexing the time-division multiplexed data of the second bit rate sent from each subscriber-side transmission device to time-division multiplexed data of the first bit rate of each respective group, and inputting the time-division multiplexed data of the first bit rate to a switch via channel units; and digital signal transmission lines for connecting each of the subscriber-side transmission devices to the switch-side transmission device; said subscriber-side transmission device having means for sensing a traffic state of each group and sending a signal indicative of the traffic state of each group sensed; and said switch-side transmission device including: channel units for inputting the time-division multiplexed data of the first bit rate the number of the channel units of for inputting the time-division multiplexed data of the first bit rate being smaller than a total number of groups; demultiplexing means for demultiplexing the time-division multiplexed data of the second bit rate sent from each subscriber-side transmission device to time-division multiplex data of the first bit rate of each respective group; a connecting circuit for connecting, to a prescribed channel unit, a respective line which sends the demultiplexed time-division multiplexed data of the first bit rate; and a connection controller for controlling the connecting circuit, based upon traffic information sent from the subscriber-side transmission devices, to connect, to an unused channel unit, each line which sends the demultiplexed time-division multiplexed data of the first bit rate in a group to which a subscriber terminal in an off-hook state belongs.