Devices are needed to comply with a protocol so that the interrupt-ask for (IRQ) lines can be shared. The PCI bus involves 4 interrupt strains, INTA# by means of INTD#, all of which are offered to each product. As much as 8 PCI gadgets share a similar IRQ line (INTINA# https://nathanlabsadvisory.com/iso-27001-information-security/