Patent ID: 7174497

Claim:
A method of storing a number of data bits of a secondary channel ( 30 ) in the frame of a main channel ( 20 ) comprising a fixed number of main channel bits and a frame synchronization signal, characterized in that a secondary frame ( 11 ) is formed having a fixed number of frame bits, which frame bits are successively filled with a number of data bits ( 113 ), an end-bit ( 114 ), which is set to a first bit-value, and filling bits ( 115 ), if any, which are set to a second bit-value, wherein the number of data bits ( 113 ) is dependent on and smaller than a random number (n j ) of bits being available in the frame of the main channel ( 20 ) for storage of bits of the secondary channel ( 30 ), that the secondary frame ( 11 ) is then encoded using an error correction encoder ( 39 ) producing encoded data bits ( 113 ) and parity bits ( 112 ) and that the encoded data bits ( 113 ) and parity bits ( 112 ) are embedded in the frame of the main channel ( 20 ).