| 摘要 |
A system and method for reducing the probability of deadlock conditions caused by the repeated transmission of data frames containing data sequences equivalent to those used by serial data communications equipment for inter-device signalling uses a technique wherein a link data input is scrambled for transmission over a channel. The system comprises a commonly used scrambler modified so that a selector is placed in the path of the scrambled data which is to be transmitted and fed back to a shift register. The selector also can select unscrambled generated signalling patterns for transmission through the channel. At the remote end of the channel, a receiver circuit comprises a commonly used self-synchronizing descrambler for reproducing the unscrambled link data at the output. The receiver circuit also comprises signalling pattern detectors for detecting the unscrambled signalling patterns. Patterns are generated at the transmitter and sent to the channels by the selector. In the event that the transmitted scrambled data matches a signalling pattern at one of the detectors, this portion of the scrambled data may be lost. However, a deadlock condition resulting from repeated efforts to send the same link data which failed because of detection by one of the signalling pattern detectors will not occur because each identical frame of link data will generally result in a different frame of scrambled data.
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