System, methods and apparatus are described that support multimode operation of a data communication interface. A method includes receiving a first code word transmitted while a physical interface of the device is configured to operate in a low-power mode of operation, reconfiguring the physical interface in response to the first code word such that it operates in a high-speed mode, transmitting data while the physical interface operates in the high-speed mode of operation, receiving a second code word transmitted while the physical interface operated in the high-speed mode of operation, and reconfiguring the physical interface in response to the second code word, such that it operates in the low-power mode of operation. The first code word, the second code word, and the data may be transmitted in signals bound by a common voltage range. In one example, the voltage range is less than 600 millivolts.