Data communication device and data communication system having the same

A data communication system comprising:

• a data transmission line section comprising a plurality of data transmission lines arranged in parallel;
• a first communication module section comprising a plurality of first communication modules arranged in parallel and is being connected to one end of the data transmission line section;
• a second communication module section comprising a plurality of second communication modules arranged in parallel and is being connected to the other end of the data transmission line section;
• wherein the first communication module is configured to convert a TX signal of a voltage level, provided by an external device, into a TX signal of a current level and output the converted TX signal to one side of the data transmission line, in order to communicate solely using current, free from interference between the capacitive load present on the data transmission line and the data transmission line,
• the second communication module is configured to convert an RX signal of a current level, provided via the data transmission line, into an RX signal of a voltage level, in order to communicate solely using current, free from interference between the capacitive load present on the data transmission line and the data transmission line, and
• the first communication module and the second communication module each include a mode switching switch that allows switching between a data transmission mode and a data receiving mode, or between a data receiving mode and a data transmission mode, controlled by a communication direction control signal, enabling bidirectional communication.