INT 2F C - PTS-DOS 6.51, S/DOS 1.0+ - "EMPTY" (RESERVED FOR INPUT STRING)
	AX = 1260h
	ES:DI -> string buffer (see getstr)
	DL = extended keystroke code or FFh if ENTER
Return: AX = 0000h (default handler in the kernel)
	CF set if action done, all registers preserved
Notes:	This function is known to be handled by Paragon Technology Systems
	  PTS-DOS 6.51 and S/DOS 1.0, and probably was also handled
	  in earlier releases.
	The default handler in the kernel justs XORs AX,AX and returns.
	This is reserved to be invoked in input string