Units Are required to adhere to a protocol so that the interrupt-request (IRQ) lines may be shared. The PCI bus involves 4 interrupt lines, INTA# through INTD#, all of which are available to every product. As much as eight PCI gadgets share the same IRQ line (INTINA# via INTINH#) in https://nathanlabsadvisory.com/cybersecurity-fintechs/