INT 0Bh (11) (IRQ 3)

        This interupt is called by hardware 8259-1, IRQ 3.

        Used by one or more of the following adapters:

                COM 2, RS-232 Serial Handler
                BSC Adapter,
                3278/79 Adapter (altlternate),
                SDLC Adapter,
                PC Net Adapter (alternate),
                Cluster Adapter (primary)