Data transmission system (1), comprising: a master-side
data transmission device (1a) configured to perform
bidirectional communication with a slave side via a single-wire
transmission line (L1); and a slave-side
data transmission device (1b) configured to perform
bidirectional communication with the master-side
data transmission device (1a) via the
transmission line (L1), wherein the master-side data transmission device (1a) includes: an input-
clock-side
transistor (MN1) connected between a reference potential and the
transmission line (L1), which is configured to perform the switching according to an input
clock; a first
transistor (MP1) connected between a first potential and the transmission line (L1); a second
transistor (MP2), one end of which is connected to a second potential which is lower than the first potential; a third transistor (MP3), one end of which is connected to the second potential; a master-side
resistor (R1) connected between another end of the second transistor (MP2) and another end of the third transistor (MP3); a connection interruption circuit (1a-1) configured to interrupt an
electrical connection between transistors two and three and the transmission line (L1) depending on the switching state of the first transistor (MP1); and a master-side data
reproduction circuit (1a-2) configured to reproduce data sent by the slave-side data transmission device (1b) via the transmission line (L1), wherein the slave-side data transmission device (1b) includes: a fourth transistor (MP4) connected between the transmission line (L1) and a third potential which is higher than or equal to the first potential; a slave-side
resistor (R2) connected between the transmission line (L1) and the reference potential; a
clock reproduction circuit (1b-1) configured to reproduce a clock (ck) sent by the master-side data transmission device (1a) over the transmission line (L1); and a slave-side data
reproduction circuit (1b-2) which is configured to reproduce data sent by the master-side data transmission device (1a) over the transmission line (L1).