I know this is dead simple for some of you, but that's why I'm asking.

I need a VGA to HDMI converter for a classroom with an old desktop machine and a new projector that they supplied with only HDMI inputs. No prob.

The sticking point seems to be a small chassis type automatic 2 in, 1 out HDMI switch. I haven't even shopped for these before so I have no go-to.

Monoprice has a pigtail unit that could work, but it's pigtails, which is not appropriate for a classroom cart. They also have a small box type switch that autoswitches, but they tell me that
a) This will switch to whichever input is on, but they can't tell me what it will do if one is on and I select the other one, and
b) The person I was chatting with "took it upstairs" for a moment and they said that these switches all switch differently so they can't promise how it will work.

Yup, they think different items of the same model will perform differently. If so, that should be discontinued right now!

Anyway, help will be appreciated. Thanks.