Help with Binary and Characters?

Dear Readers,
I am utterly confused now.

I know how to convert decimal numbers into binary but sometimes I see that character can also be converted into binary. Is that possible? Could someone give me a tiny example? Or a link?
And also what is actually meant by byte data? Like format of binary data is in 0's and 1's What format is byte data in?

Where did you see "character can also be converted into binary". I suspect this is referring to the fact that all characters are stored as numbers. These numbers only represent characters because (at least in Java), the Unicode character set is used to determine which number maps to each character. Ultimately all data in the computer is stored as binary, so the Unicode values are stored as binary.

Of course, this is just a guess. It would help if you can provide a quote so that we can see the context of this statement. Similarly, you should provide some context for the phrase "byte data".

Layne