You use a single shift when you want to display the next character from a different character set. A single shift maps the G2 or G3 set into GL. The character set is active for only one character, then the terminal returns to the previous character set in GL.
The terminal has two single-shift control functions available.
|Single-Shift Control||8-Bit Character||7-Bit Equivalent Sequence||Function|
|Single shift 2||
|Maps G2 into GL for the next character.|
|Single shift 3||
|Maps G3 into GL for the next character.|
Suppose the ASCII character set is in GL. You want to display the alpha character from the DEC Technical character set, already designated as G3. You do not want to replace the ASCII set just to display one character. Instead, you can use single shift 3 to temporarily map the DEC Technical set (G3) into GL.
single shift 3
After displaying the alpha character, the terminal maps the ASCII set (G1) back into GL, replacing the DEC Technical set (G3).