Equipment are required to observe a protocol so the interrupt-ask for (IRQ) lines is often shared. The PCI bus contains 4 interrupt lines, INTA# through INTD#, all of which can be obtained to every system. As much as 8 PCI products share the exact same IRQ line (INTINA# via INTINH#) https://nathanlabsadvisory.com/certified-data-privacy-professional-cdpp/