Category: <b>resident utilities</b>
<br>Flags: Undocumented function<p>
<pre><b>INT 16 - PC Tools v5.1+ PCShell API - INSTALLATION CHECK</b>

	AX = FFDDh
	BX = 0000h
Return: CX = 5555h
	DX = 5555h if PCShell installed in resident mode
</pre>