Devices are necessary to adhere to a protocol so which the interrupt-request (IRQ) strains may be shared. The PCI bus involves four interrupt traces, INTA# by means of INTD#, all of which are offered to each product. Approximately eight PCI products share precisely the same IRQ line (INTINA# via INTINH#) https://nathanlabsadvisory.com/iso-27001-information-security/