Products Are necessary to comply with a protocol so the interrupt-request (IRQ) traces may be shared. The PCI bus incorporates 4 interrupt traces, INTA# through INTD#, all of which can be found to every machine. Nearly 8 PCI gadgets share the exact same IRQ line (INTINA# by INTINH#) in APIC-enabled https://nathanlabsadvisory.com/pci-dss/