A keyboard device and a data communication method using the keyboard device. The data communication method includes generating, by the keyboard device, data that is a set of commands to be executed by a computer using a key input signal that is generated when a key is input, transmitting, by the keyboard device, the generated data to the computer, thus allowing the computer to execute each command corresponding to the data, and receiving, by the keyboard device, results of executing the command corresponding to the data from the computer, wherein the command includes a line coding method to be used when the computer transmits data to the keyboard device, and wherein the computer generates a toggle key signal to correspond to the line coding method and transmits the toggle key signal to the keyboard device.