Described embodiments provide for switching from a low-power mode of a device such as, for example, a SAS or SATA receiver, to an active mode. The device enters the low-power mode by shutting down i) logic devices of a physical layer of the device and ii) a decoding circuit of the device. Activity at an input of a receiver of the device is detected while in low-power mode, and the device switches, in response to the detected activity, from the low-power mode to the active mode by powering up i) the logic devices of the physical layer and ii) the decoding circuit when activity is detected, thereby responding to the detected activity as if it is a predetermined command.