Wiring Bosch D7412G

I have a 2000s-installed security system with two keypads, maybe 8 smoke detectors, a half-dozen motion detectors, and a few door sensors.

For starters, I’d like to just pull sensor data out and make it available to HA. I want to make sure I’m going down the right track before I get too far.

The panel advertises “75 points, 8 on-board and 67 off-board.” The on-board points are pretty apparent. These I’ve tapped (not removed from the panel) to inputs on my Konnected alarm panels.

First question: The label says, “Voltage ranges: Open (3.7-5.0V), Normal (2.0-3.0V), Short: (0.0-1.3V).” Is this an industry standard that Konnected will play nicely with? Elsewhere I’ve seen that the alarm panel expects an open or closed circuit. The panel also says 1k resistors are required at the end of line. I’ve seen mention that with a panel replace I should remove all these resistors. If I’m just monitoring my panel, what’s the plan here?

Second question: Since I have more than 8 sensors, I’m assuming some of those other 67 are used. There’s a small breakout board connected to the zonex terminals. I’d assumed that was for the keypads and displays. It certainly doesn’t have enough wire pairs coming in to account for the other sensors. So I’m thinking there’s another box somewhere (attic maybe? the keypads themselves?) that aggregates many sensors into a serial data bus signal that comes in here. I’m so far into speculation that I wanted to get some confirmation that this might be correct before hunting around the house for something that may not exist.

Thanks in advance!