Equipment are needed to follow a protocol so that the interrupt-ask for (IRQ) lines could be shared. The PCI bus incorporates 4 interrupt lines, INTA# via INTD#, all of which are offered to every gadget. As much as eight PCI equipment share exactly the same IRQ line (INTINA# through INTINH#) https://nathanlabsadvisory.com/merging-token-companies/