Confusing Chr$ explanation

[TempodiBasic]

I'm able to see characters for all the Alt values, but I'm unable to produce the Copyright (and some others). The Alt table says it should be Alt 0169,
but Alt + 0169 only produces the ┌ symbol (or something very similar).
When I enter  Alt + 0169  here, on the Forum, I get the © ok. Why not in my program?

The answer is in your same question! Being clearer,  QB64pe is a QB45 clone, it is standing on ASCII table, while the forum page is a webpage that uses Unicode Table. 
So 0169 in ASCII (0- 255) is equal to 169 and in the ASCII table of the IDE and of the compiler is this character  ┌
while 0169 in Unicode table (0196 = 00A9) is the copyright simbol  ©
Now I do the eco of Space_ghost, SagarS and RhoSigma
you can use  ASCII Table  external characters by using _MapUnicode to substitute an unused character with that we need.
I learnt this tip from the community when I wanted to localize to my language the input/output of keywords of QB64.
please think how is in trouble the hangman game when I must guess "papà" and not "papa"  (Dad and not the Pope) without "à" in input/output.