Equipment are required to follow a protocol so the interrupt-ask for (IRQ) lines can be shared. The PCI bus includes four interrupt traces, INTA# through INTD#, all of which can be obtained to every system. Nearly eight PCI products share the identical IRQ line (INTINA# by means of INTINH#) in https://nathanlabsadvisory.com/ensure-data-privacy-and-security-with-hipaa-compliance-services-in-the-usa/