According to one embodiment, an adapter apparatus includes a first connector conforming to the first standard, a second connector conforming to the second standard, a first transmitter and circuitry. The first transmitter transmits a first signal to a first external apparatus connected via the first connector. The first signal associates with a request to determine whether a first mode is supported by the first external apparatus. The first mode corresponds to a communication mode that conforms to a second standard via the first connector. The circuitry generates a second signal when the first external apparatus does not support the first mode. The second signal is used to make an indication representing that the first external apparatus does not support the first mode.