Gadgets are required to follow a protocol so which the interrupt-ask for (IRQ) strains can be shared. The PCI bus features 4 interrupt strains, INTA# through INTD#, all of which are available to each unit. As many as eight PCI devices share a similar IRQ line (INTINA# as a result https://nathanlabsadvisory.com/building-an-effective-incident-response-team-roles-and-responsibilities/