Just wondering if anyone has put together RS232 plug-in for a AVR-5800?
I haven’t seen one, but @Ap15e pointed out to me the other day that the denon.de site publishes a bunch of the protocol docs for their models.
eg. http://www.denon.de/site/download.php?datei=datadir/pdf/sonst/436_AVR4810CI_4810_PROTOCOL_V6.6.0.pdf
You can probably navigate around to find the correct manual, but if Denon’s amp’s share any heritage, you could likely use the codes from this guide to build a new driver.
The code in my Onkyo driver would likely be similar enough to adapt with the “right” set of codes for the '5800
http://code.mios.com/trac/mios_onkyo-media-control
… even better 
It’ll be somewhat simpler than the Onkyo eISCP since it can be done using [tt]CR[/tt] and most of the “raw” stuff I had to do can be removed.
Looking over the command codes, the implementation of “Mute” will be interesting as Vera’s Mute [tt]ACTION[/tt] is a Toggle, and the Denon’s Protocol uses Discrete ON & OFF Codes.
Not impossible, just a little bit of code that sets a flag, then makes an “inquiry call” (“[tt]MUON?[/tt]”) in the [tt][/tt] handler.
In the [tt][/tt] block, there needs to be a counterpart block of code that resets the flag if a “[tt]MUON[/tt]” or “[tt]MUOFF[/tt]” response is returned and then sends another request like “[tt]MUOFF[/tt]” or “[tt]MUON[/tt]” (to force the toggle). This will avoid the code being tripped when a user manually Toggles Mute directly on the Amp (or via IR) - at least that’s the way the Onkyo works, so I’m guessing you’d need something similar for the Denon.
Let us know if you get stuck making the modifications work.
Thanks guys.
Krfar