Devices are required to adhere to a protocol so which the interrupt-ask for (IRQ) traces could be shared. The PCI bus involves four interrupt strains, INTA# through INTD#, all of which are offered to every product. As many as eight PCI devices share exactly the same IRQ line (INTINA# via https://nathanlabsadvisory.com/the-top-benefits-of-using-ciso-as-a-service/