Devices are required to stick to a protocol so which the interrupt-request (IRQ) strains might be shared. The PCI bus includes 4 interrupt lines, INTA# by INTD#, all of which can be found to every product. Around 8 PCI devices share the exact same IRQ line (INTINA# by INTINH#) in https://nathanlabsadvisory.com/fedramp/