David...
I tried that code. I get different results. I have no "H" on page 2. None the less...I pressed every button on every screen and got no DSP changes other than the stuff I already had. (Like the toggle +/-).

Chris...
I'm using a 700. Although I bought a 500 from David as well that should be here on Wednesday. :-)
I have the Rat Shack 1994, 2104 (blah) and 2116. I used the 1994 and 2116 for all my testing this evening. I downloaded EVERY Sony DSP device off the JP1 website and tried them all. No dice on any of them. No real clue either as to what's the missing link.

Doug...
Yeah...I'm like you. I know about that site, but haven't really sat down and read it. I am NOT a protocol programmer....so some of the stuff on that site just bounces off my forehead.

Anyway...I'll post a 4es dsp question up on the JP1 site and see if anything comes back at me.