INT 14 - 3com BAPI SERIAL I/O - ENTER COMMAND MODE                              
	AH = B1h
Return: AH = return code (00h,07h,0Ah) (see #00394)
Desc:	provide a means for the application or terminal emulator to perform
	  the same action normally caused by the ECM character
SeeAlso: AH=B0h,AH=B2h