A system for powering on downstream devices includes a master device; a first slave device; and a first communication link connecting the master device to the slave device for enabling the master device to transmit data signals to the slave device. The master device includes a power-on signal generator for injecting a power-on signal onto the communication link and the first slave device includes a power-on signal receiver for detecting the power-on signal injected on the communication link by the power-on signal generator and powering on the first slave device.