A:Answer I had to search for this answer, as I already knew the HU I had just works with this cam (Excelon line).
Per Crutchfield: (https://222.crutchfield.com/S-n7druBnpCR1/p_113DRV520/Kenwood-DRV-N520-Drive-Recorder.html)
"The DRV-N520 dash cam is compatible with select Kenwood DDX, DNX, and DMX Series in-dash multimedia receivers..."
"Dashboard Cam Compatibility: The Kenwood DRV-N520 dashboard camera is specifically designed to plug into select 2017-up Kenwood DDX, DNX, DNR, and DMX series in-dash receivers. The DRV-N520 plugs into the Kenwood receiver's composite video input labeled "Front View Camera" and the 4-pin proprietary terminal labeled "Dash Cam". The dashboard camera's live and recorded video are displayed on the receivers' touchscreen. You'll also control the DRV-N520's settings and parameters from the receiver's touchscreen.
DDX Series: DDX6704, DDX6904, DDX8905S, DDX8906, DDX9704, DDX9705, DDX9707, DDX9904, DDX9905, DDX9907
DNX Series: DNX575S, DNX576S, DNX577S, DNX695S, DNX696S, DNX697S, DNX775RVS, DNX874S, DNX875S, DNX875S, DNX994S, DNX995S, DNX996S, DNX997X
DNR Series: DNR476S, DNR876S, DNR1007
DMX Series: DMX7704, DMX905S, DMX907S, DMX957X, DMX9707, DMX1037, DMX1057
Note: Compatible receiver as of 9/29/2020.