State machine and method for monitoring and controlling operating modes in a computer-controlled telephony instrument

For use with a telephony instrument having controller and audio unit portions with associated bus drive circuitry, said controller and audio unit portions couplable together by a user data bus having four audio states and a control bus, a method of allowing operating modes of said telephony instrument to be monitored and controlled, comprising the steps of:

• placing said user data bus in a first predetermined state, said controller portion responding to said predetermined state by placing said control bus in a selected state;
• detecting a presence of said selected state;
• and
• in response thereto, placing said user data bus in a second predetermined state, said second predetermined state identifying a selected one of at least two mode control states and said four audio states to which said first predetermined state corresponds, thereby to allow said user data bus and said control bus to cooperate to provide an at least six state sequential output to allow said operating modes to be monitored and controlled without modifying said bus drive circuitry.

A telephony instrument, comprising:

• a controller portion having bus drive circuitry associated therewith, said controller portion embodied in a peripheral card couplable to a computer system to allow software executable in said computer system to control said controller portion;
• an audio unit portion having user interface circuitry;
• a user data bus, having four audio states, coupling said bus drive circuitry and said audio unit portion;
• a control bus coupling said bus drive circuitry and said audio unit portion;
• and
• a state machine, associated with said audio unit portion, that allows operating modes of said telephony instrument to be monitored and controlled, said state machine including:
• a first circuit that places said user data bus in a first predetermined state, said controller portion responding to said predetermined state by placing said control bus in a selected state;
• and
• a second circuit, coupled to said first circuit, that detects a presence of said selected state and, in response thereto, places said user data bus in a second predetermined state, said second predetermined state identifying a selected one of at least two mode control states and said four audio states to which said first predetermined state corresponds, said state machine thereby allowing said user data bus and said control bus to cooperate to provide an at least six state sequential output to allow said operating modes to be monitored and controlled without modifying said bus drive circuitry.