An environmental control device, comprising: an interface terminal (222, 222a-222d); a configurable interface circuit (102, 102a-102d, 300) having: an interface connection coupled to the interface terminal; a plurality of switches (304, 306, 308, 310, 312); a first plurality of configuration control inputs (108a, 108b, 108c) that collectively define a plurality of states, each of a plurality of interface signal types being associated with a respective one of the states, each configuration control input being coupled to at least one of the switches (304, 306, 308, 310, 312) to control the activation of the at least one switch; a plurality of components coupled to the switches (304, 306, 308, 310, 312); wherein the switches (304, 306, 308, 310, 312) define a current one of a plurality of component arrangements based on a corresponding one of the plurality of interface signal types associated with a current one of the states, each component arrangement having the interface connection and at least one active component from among the plurality of components; characterized in that when the first plurality of configuration control inputs (108a, 108b, 108c) identify a third state, the switches (304, 306, 308, 310, 312) are controlled in accordance with the third state to define a third of the component arrangements that associates the interface connection with a third of the interface signal types, the third interface signal type identifying a third input type reflecting a digital input; the components include a first resistor having a first end coupled to the output of the active component and a second end coupled to the interface connection; and a second of the switches is coupled between a digital bias voltage and the second end of the first resistor; and wherein the second switch is activated when the configuration control inputs (108a, 108b, 108c) identify the third state. an interface terminal (222, 222a-222d); a configurable interface circuit (102, 102a-102d, 300) having: an interface connection coupled to the interface terminal; a plurality of switches (304, 306, 308, 310, 312); a first plurality of configuration control inputs (108a, 108b, 108c) that collectively define a plurality of states, each of a plurality of interface signal types being associated with a respective one of the states, each configuration control input being coupled to at least one of the switches (304, 306, 308, 310, 312) to control the activation of the at least one switch; a plurality of components coupled to the switches (304, 306, 308, 310, 312); wherein the switches (304, 306, 308, 310, 312) define a current one of a plurality of component arrangements based on a corresponding one of the plurality of interface signal types associated with a current one of the states, each component arrangement having the interface connection and at least one active component from among the plurality of components; characterized in that when the first plurality of configuration control inputs (108a, 108b, 108c) identify a third state, the switches (304, 306, 308, 310, 312) are controlled in accordance with the third state to define a third of the component arrangements that associates the interface connection with a third of the interface signal types, the third interface signal type identifying a third input type reflecting a digital input; the components include a first resistor having a first end coupled to the output of the active component and a second end coupled to the interface connection; and a second of the switches is coupled between a digital bias voltage and the second end of the first resistor; and an interface connection coupled to the interface terminal; a plurality of switches (304, 306, 308, 310, 312); a first plurality of configuration control inputs (108a, 108b, 108c) that collectively define a plurality of states, each of a plurality of interface signal types being associated with a respective one of the states, each configuration control input being coupled to at least one of the switches (304, 306, 308, 310, 312) to control the activation of the at least one switch; a plurality of components coupled to the switches (304, 306, 308, 310, 312); wherein the switches (304, 306, 308, 310, 312) define a current one of a plurality of component arrangements based on a corresponding one of the plurality of interface signal types associated with a current one of the states, each component arrangement having the interface connection and at least one active component from among the plurality of components; characterized in that when the first plurality of configuration control inputs (108a, 108b, 108c) identify a third state, the switches (304, 306, 308, 310, 312) are controlled in accordance with the third state to define a third of the component arrangements that associates the interface connection with a third of the interface signal types, the third interface signal type identifying a third input type reflecting a digital input; the components include a first resistor having a first end coupled to the output of the active component and a second end coupled to the interface connection; and a second of the switches is coupled between a digital bias voltage and the second end of the first resistor; and wherein the second switch is activated when the configuration control inputs (108a, 108b, 108c) identify the third state.