There is provided an integrated loopback used for on-die self-test and diagnosis of transceiver faults. According to embodiments, there is provided an interface network including an AC coupling capacitor interposed between input pins of the interface network and an input of an amplifier, a shunt capacitor interposed between the AC coupling capacitor and the input of the amplifier and a selector. The selector includes a mission mode circuit component connected to a bottom plate of the shunt capacitor and the selector is configured to select between a first mode and a second mode, wherein the first mode is mission mode and the second mode is loopback mode, wherein in the second mode the mission mode circuit component forms at least part of a circuit that supplies a loopback signal.