How ever you type it in your terminal program it gets sent just the same.

Electrically Hex, Ascii, And Dec are the same, if you put a oscilloscope on the wire it would look identical, They are just different ways of expressing the same information.

My guess is you are not telling your controller that the string you are sending is being represented by hex.

In AMX if tell the processor to send_string serial_port1, "'help'" it will send a Ascii string out of serial port 1.

If i tell it to send_string serial_port1, "$68,$65,$6c,$70" it will send a Hex string out of serial port 1.

In this case AMX interprets the $ as an identifier that i am using the hexadecimal representation of the Ascii characters.

The electrical signal it sends is identical in either case

Gee, another case where telling us the model and brand........

Hmm, I wish someone would have asked for that earlier... Like in post #2, or the initial response to OP's question.

This might be another one of those posts that goes on for few pages and dies unanswered, all because OP it tight lips and won't help us help him.
Oh well, I'll check back here in a week, see what happened.

Well, of course. I figure since he hadn't responded yet, maybe he still wasn't paying attention. So I said it again.

This, however, is really really well said, and it expresses why we sometimes get irritated with people like this: