Devices are necessary to observe a protocol so which the interrupt-request (IRQ) lines could be shared. The PCI bus features four interrupt lines, INTA# by means of INTD#, all of which can be obtained to every unit. Nearly eight PCI gadgets share the same IRQ line (INTINA# via INTINH#) in https://nathanlabsadvisory.com/hipaa-hitech-compliance/