Need plug identification on Retro 820R

[HBeil]

I'm trying to identify a plug on the input side of a 2017 Riverside Retro 820R.  No mention of it in the Manual.

 

[StirCrazy]

is your unit solar ready?  that looks like some I have seen that are solar ready where you can plug portable panels into it.  use a multi meter and see if you have battery voltage on the port.  if you do you can use it either way I would imagin

[HBeil1]

Yes it's 12v, and one rv dealer also believed it to be a solar plug with possibility of plugging in portable solar panel.  The manufacturer (Riverside) has not responded to my numerous calls for help with this id, or, the specs or requirements of compatibility.