Espruino with Glediator & LED matrix

I've tried a few different things but nothing fully working yet. I've confirmed that serial data is being correctly sent out of the PC, Espruino just can't seem to read it.
I have changed my setup to use a USB-TTL. The Espruino USB is now being use for code uploading and console. All serial data is being sent to the USB-TTL and then into Espruino on the following pins. I'm using the original Espruino board for now and my wiring for the USB-TTL Converter is RXD > C10 & TXD > C11
I don't think I can use A9&10 as I have a bluetooth module attached.

After running my test code .on('data' still isn't receiving anything. As a basic test I tried the following code with nothing connected and the results are strange, am I doing something wrong?

function onInit() {
  //Serial1.setup(115200);
  Serial3.setup(9600);
  Serial3.on('data', function (data) { console.log("<Serial3> "+data); });
  Serial3.print("Hello World");
  console.log('Code is running.');
}
onInit();

After uploading code:

>echo(0);
Code is running.
=undefined

Nothing is outputted?

After entering save():

Running onInit()...
Code is running.
<Serial3> 
<Serial3> 
> 

Serial3 is outputted but not the "Hello world"
If I set a baud rate of 115200 Serial3 isn't outputted.