Every file is a binary file :)
Like someone else stated ASCII uses the low order 7 bits of a byte to represent a symbol (i.e. character). There are some hex values that are not valid in ASCII. Use the character map application that ships with Windows to see the hex values for each symbol.
I suggest downloading a Hex Editor (I reccomend HackMan: http://www.technologismiki.com/en/index-h.html It is free. IT people usually ask why that app is installed though because of the name). Using a Hex Editor you can investigate the file byte for byte.

Hope this helps.

Einar

>I have a customer trying to transmit a NACHA direct deposit file to their bank. The bank is telling them they are sending a binary file and it needs to be ASCII. I can open the file in Notepad and it just looks like text to me. What are they talking about?