Your signal is very degraded: your rise and fall times are too slow relative to the bit rate. If the signal really looks as your scope plot shows, and this is not just a measurement issue, then it's no surprise that you cannot get coherent data out of it. Serial port signals should have very clean and well-defined rise and fall times relative to the baud rate.
To begin with, try getting the cleanest possible scope trace. Zoom in more - at the horizontal timebase that you're using, with those messy pulses, getting a good idea of what's going on is difficult. Then, make sure you're using your scope's 10x mode on the probe, and that any loading features (e.g. 75Ω termination) are off. Make sure your probe's ground is solid, and that there is nothing else on the TX line other than your scope. Then, measure again. What scope are you using?
Assuming this is a standard asynchronous serial signal, there should be a high-to-low transition marking the start of every byte (the start bit). For continuous transmissions, these should be spaced out evenly. Looking at your top plot, it looks like this might be the case, but I'm having a hard time aligning a grid like that to your bottom plot. Try to improve your signal quality as much as possible, then zoom in to a sparse (mostly-zero) section of the capture and see if you can confirm a pattern like that. If this is ASCII, you should be able to find some space characters, which are 0x20, and should be represented by the bit sequence 0000001001 (or 000000100x1 if parity is enabled, append another 1 or half of it if there are 2 or 1.5 stopbits respectively). If you can't find the evenly spaced out start bit transitions, then this probably isn't a standard UART output.
Either way, things should be a lot clearer once you solve your signal integrity issues.