Products Are needed to adhere to a protocol so that the interrupt-request (IRQ) lines may be shared. The PCI bus contains four interrupt strains, INTA# through INTD#, all of which are available to every device. Around eight PCI equipment share the identical IRQ line (INTINA# via INTINH#) in APIC-enabled x86 https://nathanlabsadvisory.com/bespoke-training/