This is a mystery signaling standard that I'm trying to sort out. It looks more or less like RS-485 to me, but I don't recognize the long looking start bit, and the "idle" state of the line looks a little strange to me. Using an RS-485 to RS-232 converter, I can't seem to get it to translate to anything intelligible. Note the different offsets for CH1 and CH2. When in the "idle" state (at the beginning) the two lines are at essentially the same potential, and when transmitting, they differ by the amounts show.
I guess in particular, I'm more curious about the framing than I am about the physical layer itself, since my rs-485 converter seems to interpret it OK (even if the data appears to be nonesense to me)
Edit:
Here's the character of the data over a longer time span, note the timebase (same vertical settings)
Here's the close-up trace, but with infinite persistence turned on. I'm triggering on the long start pulse, which seems to be present for all messages:
Best Answer
The physical layer does indeed look like RS485, but that's just describing the differential voltage drive and idle-state of the lines. A peek at whatever's driving the bus in the source kit would tell you - it'll most likely be some standard 485/422 chip.
What the data format is is a different question, for that it's easier to look at the output from a 485 chip and trace the 0's and 1's. If you are sending some known data back & forth then you should be able to determine that relationship pretty easily.
There may be some sort of messaging protocol above that, depending on the kit.