A data transmission system, and a method of passing data through a data transmission system.

摘要

In the system carrier is continuously transmitted from transmitting side (1, 2) to receiving side (4, 5).
<??>Outside effective data sending periods continuous "1" bits (ALL MARK, waveform [c] Fig. 2) are sent.
<??>To detect effective data sending periods, a code converter (22) on the transmitting side (1, 2) inverts selected data bits for sending.
<??>The bit coinciding with a send request signal rising to "1" is inverted (waveforms [b] and [d]; Fig. 2), and subsequently any bit which follows four consecutive bits of equal value is inverted whilst the send request signal is "1".
<??>A receiving side (4, 5) detector (45) detects the first inverted bit (first "0" bit) and then detects subsequent inversions. The beginning and continuation of an effective sending period are thereby determined.
<??>When no inversions are detected for a predetermined number of received bits (e.g. 48) it is determined that the period has ended.
<??>A decoder (44) restores the original values to detected invertical bits.