Method and apparatus for transmission of communication signals over two parallel channels

摘要

A technique for synchronizing run-length-limited data transmitted over two parallel narrowband communication channels, such as in a token ring local area network using fiber distributed data interface (FDDI) protocols. A serial data stream to be transmitted is demultiplexed onto the two channels by sending sequential blocks of equal numbers of bits over alternate channels. In a receiver-multiplexer, block boundary synchronization is established during connection initialization by using a property of a required HALT code to detect block boundaries received in each channel. Skew compensation is effected by comparing the times of detection of the block boundaries in the two channels, and appropriately controlling a variable delay in at least one of the channels. The technique establishes reliable block boundary synchronization and skew error compensation during connection initialization, and if there is subsequent loss of synchronization, detected transmission errors will eventually result in connection reinitialization and reestablishment of synchronization.