Devices are needed to comply with a protocol so that the interrupt-request (IRQ) strains is usually shared. The PCI bus features 4 interrupt traces, INTA# via INTD#, all of which are available to each device. Nearly eight PCI equipment share a similar IRQ line (INTINA# by way of INTINH#) in https://nathanlabsadvisory.com/copyright-currency-security-standard/