What I have found is this: 1. The OBD2 cable has a switch on it. It's labeled ACC and 24h. You toggle it manually to the mode you want to be in.
When in ACC mode, and the vehicle parked (Ignition off) the camera operates for about 15 min then shuts off. If the car is bumped hard enough both front and rear will begin recording for about 15 minutes.
2. in 24h mode, the camera is constantly on and recording until you turn it off manually (or start the car, in which case it operates as normal).
I like the 24h mode so I can leave it on indefinitely when shopping, or in a high crime area that I want recording without the vehicle being bumped. The downside of 24h mode is if you forget to turn it off and you don't drive your vehicle for about a week, you may run down the battery.
If you choose to use the OBD2 cable OR the Toyota/Lexus Hardwire cable (the other optional cable to give you a parking mode feature)...you eliminate the cable that came with the FitCamX that plugs in behind the mirror. One of these two cable alternatives plugs into the Y cable of the main camera. Both of these alternative cable options provide power to cams, from either the fuse box (the Toyota/Lexus cable connects in the fusebox) or the OBD port.
The Toyota Lexus hardwire cable gives ACC mode only, no 24/7 mode. You need the OBD2 cable for that feature, and again, with the OBD2 cable, you get both ACC mode and 24/7 mode.
There is nothing in the app that appears that isn't already there when you connect either the T/L cable or the OBD2 cable. You can control the sensitivity of the "bump" the vehicle takes from more to less sensitive in ACC mode, but I haven't tested it out. I've knocked on the window in the most sensitive mode and it didn't start the cam. That's the extent that I've tested that feature.
Attached is a pic of the obd2 connector (provided to me by FitcamX support)
The instructions on what I typed above are virtually don't exist. I got this info from back and forth with their support (which was pretty good, quick responses) and playing around with the camera in my vehicle.