INT 14 - MX5 Extended FOSSIL(Fido/Opus/Seadog Standard Interface Layer)  A standardized API for performing serial I/O, originally used by the Fido and Opus bulletin- board software and Seadog bulletin-board mailer, but now in wider use. - GET/SET MNP CONNECT SOUND LEVEL
	AX = E004h
	BH = function
	    00h get sound level
	    01h set sound level
		BL = new sound level (00h off, 01h on [default])
	DX = port number
Return: BL = sound state
Desc:	specify whether MX5 should generate beeps after an MNP connection
	  (three high beeps if successful, high then low on connection failure)
SeeAlso: AX=E002h,AX=E006h