I am looking as to how to convert FCS binary to ascii text

Converting is basically parsing data in one format and reconstructing it in another.

Do you have a problem with the parsing aspect? You have a sample implementation in addition to the spec, so maybe not.

Do you have a problem reconstructing the data in the new format? You called the format "ascii text", but that can't be right. FCS is not a text encoding, so you won't get text (ASCII or otherwise) from parsing it. FCS appears to be a format for storing a table of strings, a table of integers or a table of floats (including some meta information).

Where are you stuck? What problem are you having?