Int 21 Fn 01  - Dos 1+ - Read Character From Standard Input, With Echo     [D]

   AH = 01h

Return: AL = character read

Notes: ^C/reak are checked, and INT 23 executed if read
   P toggles the DOS-internal echo-to-printer flag
   Z is not interpreted, thus not causing an EOF if input is redirected
   character is echoed to standard output
   standard input is always the keyboard and standard output the screen
     under DOS 1.x, but they may be redirected under DOS 2+

See Also: AH=06h,AH=07h,AH=08h,AH=0Ah