A system and method for generating a frequency rich spectrum in a data stream is disclosed. A network interface comprises a substitutor module, a symbol replacement module, and an encoder module. The substitutor module replaces idle streams in a first data stream with alignment symbols, boundary symbols and disposable symbols to generate a second data stream. The symbol replacement module receives the second data stream, generates random data, and replaces one or more of the disposable symbols in the second data stream with the random data in order to generate a third data stream. The encoder module encodes the third data stream.