An NFC component includes a first interface that can be used in reader mode and is configured to be connected to an antenna via an impedance matching external circuit. A second interface can be used in card mode and in reader mode and is configured to be connected to the antenna and to the first interface via the impedance matching external circuit. An internal module includes a first detection circuit configured to deliver a first detection signal that represents the phase antenna matching quality when the impedance matching external circuit and the antenna are indeed connected between the first interface and the second interface. The internal module is further configured to deliver a check signal from at least the first detection signal.