)
Call CTSB2.SYS entry point with:
	AX = ???
	STACK:	DWORD	-> ???
		WORD	function number
			(0100h,0200h,0300h,0400h,0500h,0600h,0701h)
		DWORD	-> ???
		WORD	???
		WORD	???
Return: DX:AX = ??? or error code
		0000h:0004h invalid subfunction???
		0000h:000Bh invalid value for ???
		0000h:000Fh API call already in progress
SeeAlso: #01509