Dimmer for use with a three-way switch

A method for controlling the intensity of a lighting load from a source of AC power in a lighting control system comprising a load control device having a first load terminal, a second load terminal, and an accessory terminal and a maintained switch having a closed state for coupling said accessory terminal to one of said first load terminal and said second load terminal and an open state for decoupling said accessory terminal from said one of said first load terminal and said second load terminal;

• said method comprising the steps of:
• storing a previous state of said maintained switch;
• detecting a present state of said maintained switch;
• comparing said present state with said previous state of said maintained switch;
• and
• toggling said intensity of said lighting load between an ON state and an OFF state in response to the result of the step of comparing.

A load control device for controlling the intensity of a lighting load from a source of AC power and operable to be coupled to a maintained switch, said load control device comprising:

• a first load terminal adapted to be coupled to said source of AC power;
• a second load terminal adapted to be coupled to said lighting load;
• an accessory terminal adapted to be coupled to said maintained switch, such that when said maintained switch is in a closed state, said accessory terminal is coupled to one of said first load terminal and said second load terminal, and when said maintained switch is in an open state, said accessory terminal is not coupled to either of said first load terminal and said second load terminal;
• a controllably conductive device coupled between said first load terminal and said second load terminal for controlling the amount of current flowing through said lighting load;
• and
• a microcontroller coupled to said controllably conductive device for controlling said lighting load between an ON state in which a current flows through said lighting load and an OFF state in which substantially no current flows through said lighting load, and operable to determine whether said maintained switch has changed between said open state and said closed state, said microcontroller operable to control said lighting load between the ON state and the OFF state in response to determining that said maintained switch has changed between said open state and said closed state.