Category: <b>electronic mail</b>
<p>
<pre><b>INT 16 - Shamrock Software EMAIL - CHECK FOR USER FUNCTION COMMAND-WORD</b>

	AX = 4504h
	DL = port number (01h = COM1)
	ES:BX -&gt; 80-byte buffer for ASCIZ user input line
Return: AX = 4D00h if EMAIL installed on specified port
	    DL = flags
		bit 0: user function supported (always set)
		bit 1: user entered user-function command word
	    if DL bit 1 set,
		ES:BX buffer contains line entered by user which begins with
			the defined command word and has been converted to all
			caps
Note:	caller must process the returned commandline and invoke AX=4505h
	  within five seconds with the result of that processing
SeeAlso: AX=4503h,AX=4505h
</pre>