Quick rundown of what I'm using. Arduino UNO r3, BLE shield, and an rs232 shield. I'm basically taking a serial datastream from some hardware and adding a small bit of logic and sending it over Bluetooth. Conveniently the hardware manufacturer has a simulator program for windows. My arduino handles the simulator's datastream without issues, but when I connect the arduino to the actual hardware its a no go. The rx light is on but I get nothing from Serial.available(). I have also hooked the hardware up to a computer using a serial to usb adapter and used realterm to look at the serial stream that also comes through without issue. In my attempts to figure a few things out I change the baud rate at serial.begin all around and not matter what I set the baud rate to the arduino always read the data cleanly. The simulator doesn't have any settings for the baud rate but shouldn't changing the baud rate on the arduino side jumble up the data?
A couple other things I noticed when switching to the hardware vs the simulator is that the RX light blinks with the simulator but when hooked up to the hardware is almost solid lit, I also noticed that the tx light seems to be lit too when hooked up to the hardware, although not so bright. I'm only reading the serial steam, I never write to the Serial tx line so why would this happen? The tx light never blinks when hooked up the simulator on the PC.