Method for establishing and maintaining synchronization between communicating multiplexers using checksum values

Abstract

Methods for establishing and maintaining synchronization between communicating multiplexers are provided, wherein a first multiplexer having a frame format multiplexes at least data according to the frame format, and wherein the second multiplexer demultiplexes at least said data according to the frame format, and synchronization is established by: providing the frame format with bit positions for a plurality of bits including first predetermined bit positions for a plurality of checksum bits, and second predetermined bit positions for bits other than checksum bits; calculating a checksum for the bit values of bits located at said second predetermined bit positions, and inserting bits representing the said calculated checksum into said first predetermined bit positions; sending bits including bits located at said first and second predetermined bit positions in said frame format from said first multiplexer to said second multiplexer; and establishing synchronization between said first and second multiplexers by using said bits representing said calculated checksum. In establishing synchronization, the second multiplexer chooses an arbitrary bit as the first bit in the frame. Received bits located at distances from the first bit which are equivalent to the second predetermined bit positions are then used to calculate a checksum. Bits are then located at distances from the first bit which are equivalent to the predetermined first positions. If the checksum calculations do not correspond to the found checksum bits, frame synchronization is not established. The process is then repeated starting with the next bit after the arbitrary point, and continued until the calculated checksum agrees with the bits at the checksum locations.

Dependencies are inferred from the claim text.