Extension device for a computer system capable of operating in at least three states of power management

摘要

Described is an extension device for use with a computer system which includes a memory for storing an application program which can perform at least one software function. A modem is operative to encode the at least one software function to first tone signals and transfer them onto a telephone line. The modem is further operative to decode second tone signals received from the telephone line and transfer the first tone signals in response thereto. The system includes power management circuitry (PMC) for changing the system from a low power state to a normal operating state responsive to a wake up control tone signal. The extension device includes a keypad for inputting (1) command signals corresponding to the at least one software function and (2) a wake up command signal. A display is included on the extension device for displaying information related to the at least one software function. The extension device also includes a controller coupled to a signal generator and a signal decoder. The controller and signal generator are operative to convert (1) the wake up command signal to the wake up control tone signal and (2) the command signals to the second tone signals. The controller and signal decoder are operative to decode the first tone signals to control the extension device to operate in accordance with the at least one software function.