Equipment are necessary to stick to a protocol so that the interrupt-ask for (IRQ) lines may be shared. The PCI bus incorporates 4 interrupt traces, INTA# through INTD#, all of which are offered to each device. Approximately eight PCI units share the exact same IRQ line (INTINA# through INTINH#) in https://nathanlabsadvisory.com/nerc-cip/