Help System (web edition)

ALT-F7:CODE
  CODE types characters not readily available on the keyboard.
     At first prompt 'CODE?' is displayed and the decimal value
     of the character is entered. CODE holds this character until
     it is changed by pressing PREFIX and then CODE.
     If no code value is given, CODE will be the current character
     indicated by the cursor. Another way to type special characters
     is provided by the key combination PREFIX P. (See PREFIX)