INT 21 - TopWare Network OS v5.10+ - CANCEL TopShow FUNCTION                    
	AX = FFBCh
	CH = printer number (00h LPT1, 01h LPT2, 02h LPT3)
	CL = printer server station address or 00h for local printer
Return: AL = status (00h successful, else failed)
SeeAlso: AX=FFBBh