This PCI Fault Insertion card is designed to simulate common faults on two wire communication interfaces such as CAN Bus. This card supports 4 or 8-channels of two wire serial interfaces. Each channel can simulate an open fault in either or both wires, a short between both wires or a short to one of eight externally applied fault connections, such as a battery connection or ground, via four fault buses. Each channel can support up to 0.3A and is rated to handle up to 100V between the wire pairs. The wire pairs have controlled transmission line impedance suited to most differential pair signalling systems, including fast CAN Bus interfaces and RS232. Each fault bus is capable of carrying 2A allowing multiple channels to be connected to the same fault condition. Additionally, each fault bus features a changeover relay to allow the user to connect alternative fault conditions to the fault buses.