Thanks for reaching out!
First of all, I'd like to point out that Edison's UART bus also requires the new line and carriage return. So, you should also add those signals when communicating from the RN2903 to Edison.
Now, addressing the main issue, do you have access to a logic analyzer? If so, could you please check the signals that are sent from the RN2903 to the level translator, to the Edison and vice versa?
It is important to verify that the signals are congruent, because if they are not, the issue might be found in the level translator and not on the RN2903 or the Edison. And in my experience, this is the most common issue when working at different voltage levels. The issue is mainly due to the switching rate, as the chip may not be fast enough to transfer the correct signals when translating them.
So, this should be a good place to start. But, while doing so, make sure that what you are sending on your code is actually what is reflected on the signals.
Let me know how it goes.
I used a logic analyzer and verify that the ASCII LoRa RN2903 arrived perfectly, including the \r \ n.
Comparing the UART communication between the USB - Serial converter and the one sent by Edison seems that Edison is a little bit quicker.
I attached the logic analyzer screen and table for your review and insight.
Thank you for sharing this information with us, it is of much help. However, I'm confused, I'm not sure what these readings represent. I mean, what does the first (and the second) picture represent? Is it the signal sent from the RN2903 to the level translator? Or, is it the signal from the level translator to the Edison? Or, is any of those but vice versa?
It would be really helpful if you could post a picture of every stage of the communication in order to be able to compare them.
What you mentioned about Edison being quicker than the RN2903 confuses me. Is this because of the level translator? Or are they simply different?
I noticed that you mentioned that the \r\n signals arrive correctly, but, is this both ways? Could you please confirm that you are also sending the new line and carriage return signals when communicating from the RN2903 to the Edison?
I will be waiting for your response.