A data communication device or system includes a preamble unit and a data interface. The preamble unit generates or detects a first preamble having a first length for a first data line, and generates or detects a second preamble having a second length for a second data line. The first length is different from the second length, and data on the first and second data lines form parallel data. The data interface communicates a first data with the first preamble via the first data line and communicates a second data with the second preamble via the second data line. The respective length and/or respective pattern of each preamble are adjustable and/or programmable.