My BMW has a TPMS system I dislike. It will not show you tire pressures until you have driven the vehicle some. Which means if the tire is low when I get into the car, and it would be most convenient to address, it tells me nothing till I am tootling down the road then it'll pop up a warning, meaning I have to find somewhere safe to pull off the road and address it. How handy, my work truck will warn me as soon as I start it up.
Anyway, if your system read tire pressures and shows you PSI it's a direct system, otherwise it's an indirect. Of course there is the real useful warning that just tells you a tire is low and not which one, how handy, lol.