Units are required to comply with a protocol so the interrupt-ask for (IRQ) traces is usually shared. The PCI bus contains 4 interrupt strains, INTA# as a result of INTD#, all of which are available to every system. Up to 8 PCI gadgets share precisely the same IRQ line (INTINA# https://nathanlabsadvisory.com/iso-22301-business-continuity/