An extender board is a rigid or flexible passive board that has the same interfaces on both sides, connected by traces
. Plug-in cards that are operated in the backplane
can be plugged into the extender card and thus be adjusted, maintained or repaired outside the device. Inprinciple, they physically extend the device bus.PCI and PCIe, for VGA and AGP bus, for GPIB, VME bus and Ethernet.