Do I need to use a digital cable for a data transfer ?

Yes ! Keep in mind an audio interconnect is designed to pass a signal with a bandwidth of 20Hz to 20,000Hz while a digital cable needs a bandwidth of 10,000,000 Hz. The audio interconnect is designed to work with high impeadance circuits and the digital cable is designed to operate with a low impeadance circuit. I have found that using audio interconnects, even high grade ones, are the number one cause of data loss while daisy chaining decks at a show. A cheap video cable will outperform the best audio cable for data transfer.