Compatibility issues with old ANSI codes prevent the entry of all Unicode characters.
After adopting Windows to Unicode, the entry of all Unicode characters by the same method was desired, and achieved by some applications, but couldn't be spread to all system. Codes with a preceding 0 represent the new ANSI codes.įor the last two decades, Unicode is being adopted by many systems. Three-digit codes represent the OEM codes. The new set was named ANSI(later changed to Windows codes), and the old ones called as OEM(original equipment manufacturer) code pages. These codes became so popular so that Microsoft, even though developed a new set of codes, decided to keep them. The system which interprets this action and places the corresponding character at the cursor's location is BIOS. IBM developed a method to place the characters that can not be typed by a keyboard on the screen: while keeping the Alt key down, typing the code defined for the character via the numeric keypad.
