Products are needed to abide by a protocol so which the interrupt-ask for (IRQ) lines may be shared. The PCI bus involves four interrupt strains, INTA# by INTD#, all of which can be obtained to each device. As much as 8 PCI products share the exact same IRQ line (INTINA# https://nathanlabsadvisory.com/3rd-party-security-audit-assessment/