Patent ID: 7203773

Claim:
An apparatus for using a control port to operate in accordance with multiple signal protocols comprising: an interface controller comprising a line driver, a system interface and a plurality of protocol drivers each defining at least one signal characteristic, the system interface operable to receive a configuration instruction from a main processor and the line driver operable to communicate data on a data input line and a data output line, and control signals on a direction control line and a modulation control bus comprising a modulation polarity line, a modulation enable line, and a modulation carrier signal, in accordance with the configuration instruction; and a control signal processor connected to the control port and to the interface controller via the data input line, the data output line, the direction control line and the modulation control bus, the control signal processor comprising: an infrared (IR) modulator unit operable to modulate the data output line in accordance with the modulation control bus; an output function to couple the IR modulator unit data output line to the control port in accordance with a first direction state on the direction control line; and an input function to couple the control port to the data input line in accordance with a second direction state on the direction control line; wherein the interface controller is operable to set the modulation polarity line to a state in accordance with the selected protocol driver and to set the modulation carrier signal to a frequency in accordance with the selected protocol driver.