Recently I needed to communicate with device and answer to its requests via COM port. Answers had to be fast and I wanted to see complete communication. Request/Response option of com port terminal - development tool was perfect tool for this problem. Here is the tutorial on how to use it. Sometimes manual answering to com port commands is just too slow and there is no need to do it that way. Also, if you have NO application programming experience there is no need for that too.
Just use COM port terminal - development tool. Click on Request/Response button.
Define strings that terminal will react to when they are received on COM port. Define responses that will be sent to COM port when incoming string is recognised.
In this example I connected two COM ports with each other, COM10 and COM11. I started two terminal tools: one with predefined Request/Respons, and second as normal terminal just for communication. Second terminal actually imitates device you want to comunicate with. In second terminal I predefined few macros so I do not have to type text every time.
These macros are the same as predefined text in first terminal Request/Response table. When COM11 (in my case) sends string to COM10 that has terminal with Request/Response table defined, it answers to it. One unknown macro is added to show that first terminal cannot recognise it and the terminal does not answer anything. See how it all works on video below: