Units are required to abide by a protocol so which the interrupt-request (IRQ) lines is usually shared. The PCI bus consists of 4 interrupt traces, INTA# as a result of INTD#, all of which are offered to each product. Nearly eight PCI products share the exact same IRQ line (INTINA# https://nathanlabsadvisory.com/the-top-benefits-of-using-ciso-as-a-service/