A secure mechanism for remotely controlling the power-on state of a host computer: A microcontroller in the host computer is supplied with standby power even when system power to the host computer is turned off. The microcontroller senses the state of the host computer's RS-232 receive line so that commands may be sent to the microcontroller over an RS-232 connection to the host computer. An output of the microcontroller is logically ORed with the output of a power switch debounce circuit of the host computer. The output of the logical OR function is used to manipulate the power-on state of the host computer. The microcontroller may be programmed to respond to numerous commands.