Products are required to abide by a protocol so that the interrupt-request (IRQ) strains might be shared. The PCI bus involves 4 interrupt lines, INTA# by way of INTD#, all of which are available to each machine. Approximately 8 PCI gadgets share a similar IRQ line (INTINA# by means of https://nathanlabsadvisory.com/copyright-currency-security-standard/