Int 6B Fn 0700 - Novell Nasi/nacs, Ungermann-bass Net One Serial I/o - G [S]
AX = 0700h
Return: CH <> 00h if connection active
Notes: this function is also supported by TelAPI and NPC NCSI
Novell TelAPI returns CX=FF01h and CF clear
See Also: AH=02h,AH=10h