An apparatus includes a communication circuit coupled to a communication link, a wakeup detector, and a power control circuit. The communication circuit has a first state and a second state. The power consumption of the communication circuit is lower in the second state than in the first state. The wakeup detector is coupled to the communication link. The wakeup detector generates a wakeup signal to cause the communication circuit to make a transition from the second state to the first state in response to an occurrence of an event on the communication link. The power control circuit selectively supplies power to the communication circuit in response to the wakeup signal.