@AdrianMaire About ""::" has several meanings, usually to access static parameters. In this case, "std" is a namespace used for all the STL (standard library of C++). And "array" is one of the data-structure of it." Last time I did not read your lecture too carefully. After reading more references, I more thoroughly understand the meaning of the symbol "::".

Thanks a lot. So I now know that "std" means "namespace" for STL. This is an important clarification for me, though I am not sure C++ "namespace" means the same thing as in C# (which I found very good, but not readily available in Rpi) and LUA and python. Anyway, you clarified most of my C++ confusion (except virtual function, which I think it is too hard for me now, so I will just skip it and start playing with my new toy. :)

I have just collected my toy TTLinker Mini. I plan to begin testing tomorrow.

There is a typo error in the above image. C = HC34 should read C = SC34. I cannot delete the image. So I just reloaded. My apologies.

I have been searching for updated FeeTech communication protocol. But so far I have found only the following two references, which I have already told you some days ago, and repeated below.

So now I am reading the above two references a second time, to see if I can find something like (1) Command packet, (2) status/return/reply packet. So far I can only read the Arduino Library's example programs to guess the command and status packet spec. But this is not efficient. Anyway, will do some trials and errors tomorrow.

Bed time. See you tomorrow.