A portable electronic device includes an earphone jack capable of receiving different types of earphone plugs, a switch, a detecting terminal, and a controlling terminal. The switch is connected to the earphone jack, and capable of switching between a first state and a second state. The detecting terminal is connected to the earphone jack by the switch, and capable of detecting the type of the earphone plug received in the earphone jack. The detecting terminal is connected to the earphone jack by the switch, and capable of detecting the type of the earphone plug received in the earphone jack. The controlling terminal is connected to the switch, and switches the switch to either the first state or the second state according to the type of the earphone plug.