Format of parameter block for function 4Ch:
Offset	Size	Description	)
 00h	WORD	flags
		DISPLAY.SYS = 0000h
		PRINTER.SYS bit 0 clear to prepare downloaded font, set to
			prepare cartridge selection
 02h	WORD	length of remainder of parameter block
 04h	WORD	number of code pages following
 06h  N WORDs	code page 1,...,N