INT 6B - NPC NCSI EXTENDED SERIAL I/O - LOG AND/OR INITIALIZE VIRTUAL CIRCUIT AH = 16h AL = virtual circuit number CL = ??? switch (00h, ???) Return: CF clear if successful AL = virtual circuit number CF set on error ??? Note: this function is also supported by TelAPI, which always returns CF clear and AL=00h SeeAlso: AH=11h,AH=12h,AH=17h