Okay thank you it is good to know. I already have the LED circuit with resistors and transistor and the receiver circuit with the photodiode and amplifier as well, I know it is working only in short distances but this is what I have to do (it is a university project).
So that means I can connect the LED circuit to the 1 pin (which is tx) and the photodiode to the 0 pin (which is rx) ?