Devices are necessary to adhere to a protocol so the interrupt-ask for (IRQ) strains could be shared. The PCI bus consists of 4 interrupt traces, INTA# via INTD#, all of which can be obtained to every unit. Nearly 8 PCI units share the same IRQ line (INTINA# via INTINH#) in https://nathanlabsadvisory.com/adhics-compliance/