Forward Error Correction (FEC) is used to assure optimal performance. It is based on Reed-Solomon coding and it must be implemented. The size of the Reed-Solomon codeword is , in which the number of check bytes and codeword size vary depending on the number of bits assigned to either fast or interleaved buffer.
The Reed-Solomon codewords in the interleave buffer are convolutionally interleaved. The interleaving depth values are either 16, 32 or 64 (32 or 64 for 2.048 Mbit/s based systems).