Category: <b>serial I/O</b>
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<pre><b>INT 14 - COURIERS.COM - CHECK IF PORT BUSY</b>

	AH = 81h
	AL = port number (1-4)
Return: AH = status
	    00h port available
	    01h port exists but already in use
	    02h port nonexistent
Program: COURIERS is a TSR utility by PC Magazine
SeeAlso: AH=83h,AH=8Dh
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