Compatibility: 1.0+
Expects: AH    07H
Returns: AL    character fetched from the Standard Input
Info: Reads (waits for) a character from the Standard Input Device,
returning that character in AL.  The character is not displayed.

Notes:   Does not check for Ctrl-Break.
  Call twice for Extended ASCII.
  Use Fn 0bH to check status before calling (if you don't want to
wait for a key).

- -

DOS Fn 07H: No Echo Unfiltered Console Input