I'm controlling a bunch of these all over at a large site I'm working on and they are pretty easy to talk to.  I haven't found any issues or mistakes with the protocol manual.

The < and > are literal, and there is no extra delimiter after the ">" char.  A sample command should look like:
"< SET LED_COLOR_MUTED RED >"

Just open a TCP/IP client port to them on port #2202 and you should be good to go.  Another note, is that for control, you need to connect to the "control IP address".  I believe these things get 2 different IP addresses when setting them up, one is a Dante IP, and the other is a Control IP.  The Dante IP is specifically for passing audio between other Dante endpoints, and the Control-IP is for setup and controlling them with the API commands.  Pretty straight forward.

-jason