INT 17 - NorthNet Jetstream API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running.  Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes. - INSTALLATION CHECK
	AH = F0h
	DX = printer port (0-3)
Return: AX = 0001h Jetstream present
	     else  non-Jetstream port
Note:	NorthNet Jetstream is a high-performance DMA-driven parallel card able
	  to drive printers at up to 80000 characters per second