Products Are required to observe a protocol so that the interrupt-request (IRQ) strains might be shared. The PCI bus contains 4 interrupt strains, INTA# by way of INTD#, all of which are available to each product. Around 8 PCI devices share the exact same IRQ line (INTINA# via INTINH#) in https://nathanlabsadvisory.com/pci-dss-training/