PURPOSE: To attain time division exchange of a multiple access signal while preserving timewise sequence in a frame by using a channel frame for two frames even if there is a difference in the frame phase between the input and output.

CONSTITUTION: When the frame phase between the input and output is not coincident, it is possible to read a signal of one preceding frame before an input signal is written in the phase from the head of the frame of an output signal till the end of the frame of the input signal. Thus, the time switch applies control to read a signal written in one preceding frame in a multiple access signal required for exchange between time slots in the phase from the head of the frame of the output signal till the end of the frame of the input signal to preserve timewise sequence of the multiple access signal in the frame. Thus, the time switch acts like a frame aligner when the frame phase between the input and output highways differs.