Google up ascii tables and you'll get lots of links to "hex to ascii" conversion.

Its been a while since I've dump hex out of HT and if I have time today I'll try it.
What Prefect is saying is create a file which will dump out the appropriate bytes in sequence. So in this case it will need to dump out 83(hex) or 131 (dec). You can't just type 83 or 131 as HT will send out the ASCII for 1, then 3, then 1. It needs 131 as a byte, which is an extended ascii.
I'll try to get to it this afternoon. Like I said its a pain.