Infrared interface

I tried this over and over again but I couldn't make it work.

I used the Arduino codes with the connections given. Even tough I receive code I cannot send it. Realterm is updated and there is no hex button on the send section.

On the other hand I want to receive and send air conditioner remote data. I am not sure if I can do it with Arduino.

My uart is: https://www.aliexpress.com/item/Smart-Electronics-PL2303-PL2303HX-USB-to-UART-TTL-Cable-Module-4p-4-pin-RS232-Converter-Serial/32328101959.html?spm=2114.13010608.0.0.rTj61j

What should I do?