Time-division multiplexing communication system for performing a plurality of communications having different data speeds

摘要

A communication system in which a plurality of terminal devices connected to a loop transmission line perform data transmission/reception in a time-division multiplexing manner by using a communication frame circulating the transmission line. The communication frame being constituted by a plurality of sub-frames, each including a plurality of time slots. Each of the terminal devices is arranged to perform data transmission/reception using a designated time slot in a designated sub-frame. All the sub-frames in the communication frame are allotted to a terminal device of a high capability of data transmission, while less than all of the sub-frames are allotted to a terminal device of a low capability of data transmission. A plurality of low speed terminal devices, to which sub-frames different from each other have been respectively allotted, commonly use a time slot of the same number, so that each of the time slots in the communication frame can be effectively utilized.