Equipment are needed to observe a protocol so the interrupt-request (IRQ) strains might be shared. The PCI bus incorporates four interrupt strains, INTA# by way of INTD#, all of which can be obtained to each product. As many as eight PCI products share the exact same IRQ line (INTINA# by https://nathanlabsadvisory.com/ensuring-secure-payment-processing-with-pci-dss-compliance-certification-in-the-usa/