Gadgets are required to follow a protocol so which the interrupt-request (IRQ) lines is usually shared. The PCI bus includes 4 interrupt lines, INTA# by means of INTD#, all of which can be obtained to every unit. As many as 8 PCI units share a similar IRQ line (INTINA# by https://nathanlabsadvisory.com/iso-27001-information-security/