The ASCII code

To find the position of a character in the table in HEX , combine the column digit and the row digit
For example letter Q is in position hex 51 because the column number is 5 and the row number is 1.

Each upper case character is 32 positions before the corresponding lower case character

Columns 0 and 1 contain the control codes which are unprintable.

BS=BackSpace , TB=Tab , LF=LineFeed , FF=FormFeed , CR=CariageReturn