FIELD: data transmission. SUBSTANCE: multiplexing synchronous/asynchronous data bus has three communication lines (T,R,C, 109) used for transmitting bidirectional synchronous data between at least two data units at relatively low transmission speed. Pluduplex asynchronous data are transmitted at higher transmission speed over one of three lines (R) of data bus when its other lines (T,C) are held in high logic potential state. EFFECT: enlarged functional capabilities. 18 cl, 12 wdg
