A method of transmitting data from a timing controller to a source driving device in a liquid crystal display is disclosed. The method of the present invention comprises the steps of: (a) providing a setup/hold time; (b) transmitting a test pattern from the timing controller to the source driving device using the setup/hold time; (c) returning an acknowledge signal from the source driving device to the timing controller when the test pattern is successfully received by the source driving device; (d) providing a new setup/hold time and repeating Steps (b) and (c) using the new setup/hold time when the test pattern is not successfully received by the source driving device; and (e) transmitting the image data from the timing controller to the source driving device using the new setup/hold time upon receipt of the acknowledge signal. Therefore, the use of the setup/hold time adjustment pins is eliminated.