well, an ascii file is a binary file... just the bits happen to be easily
displayable as letters, number, and other symbols. you will have to find
out what the meaning of each bit in the binary file is, how the bits are
grouped into bytes, and how the bytes are grouped into higher order things.
then read the file with the appropriate file access method and write it out
after translating the bits to whatever ascii codes you want them to come out
as. sorry i can't be more specific, but when you ask a very wide open
question you get a very wide open answer.