uh, what platform are you writing this on?

if I send "$08,$01,$20" in most platforms,
the target is going to receive

$08,$01,$20

in Crestron, the escape sequence would look like
\x08\x01\x00

in AppleScripts, it would look like
(ASCII character 8) & (ASCII character 1) & (ASCII character 20)

etc...

I think the first obstacle you have to find is the proper escape sequencing to display hex character as hex characters, rather than as literal expressions of ASCII characters representing hex characters. Does that make sense? I could be wrong, perhaps I just don't recognize the string format that your examples show.