| 摘要 |
<p>The present invention relates to a two-directional data communications system comprising a first device (12) for transmitting and receiving data, a second device (14) for transmitting and receiving data, and communications links (16, 18) coupled to the first and second devices for transferring data therebetween. According to the invention the communications system is characterised in that the first device comprises means for establishing a communications link over the communications system and for subsequently transferring data to the second device over the link and the second device comprises means for transferring, using the same communications link, a data transfer direction turnaround message to the first device and means for subsequently transferring data to the first device.</p> |
