Equipment Are required to follow a protocol so which the interrupt-request (IRQ) strains might be shared. The PCI bus involves four interrupt traces, INTA# by means of INTD#, all of which are available to every unit. Around 8 PCI gadgets share a similar IRQ line (INTINA# by way of INTINH#) https://nathanlabsadvisory.com/copyright-currency-security-standard/