I have a touch screen that is outputting data via a Serial connection at a baud rate of 115200 (RS232 DB9). I have hooked up a Sparkfun RS232 Shifter SMD to an Arduino Uno, however I don't receive anything. I have tested receiving on other serial devices (Redpark iOS Serial Cable) and it works fine.
It's worth noting that the Sparkfun RS232 module has leds for TX and RX, the TX usually blinks when it is receiving data (quite brightly), however when I am receiving data from the touch screen (touching it) I see that it does blink, but very faintly. The touch screen uses a USB to power itself, and I assume it operates on 5V (making the 12V serial connection not plausible). Is there anything I can do to boost the power, or does anyone see any other issues with this setup that I have missed?
Try lowering the baud rate. I have read in several places that the 115200 baud rate on the 16Mhz crystal leads to corrupt data and present other issues.
The touch screen uses a USB to power itself, and I assume it operates on 5V
Mostly the LCD use 4.5 to 5v for driving the logic chip whereas you can also checkout the datasheet that i think one must refer to before even connecting it.(The back light current is + logic driving voltage and consumes upto 200mA's max in case of GLCD with limiting resistors)
have you checked your RX and TX connectivity are they hooked in the right way?
I have checked the TX/RX connectivity, it works fine with a Redpark iOS Serial Cable. Also this touch screen is a projected capacitive touch screen (so it's not really a screen with a backlight, just the touch component).