Gadgets are required to observe a protocol so which the interrupt-ask for (IRQ) lines can be shared. The PCI bus involves four interrupt lines, INTA# by way of INTD#, all of which are offered to every device. As much as eight PCI units share precisely the same IRQ line (INTINA# https://nathanlabsadvisory.com/maximize-business-trust-and-security-with-hitrust-compliance/