Devices Are necessary to comply with a protocol so that the interrupt-ask for (IRQ) traces can be shared. The PCI bus features 4 interrupt strains, INTA# by means of INTD#, all of which are offered to every gadget. Nearly eight PCI gadgets share a similar IRQ line (INTINA# via INTINH#) https://nathanlabsadvisory.com/nerc-cip-compliance/