An apparatus is provided for a switching interface for a first receiver, a
second receiver, and a resistor ladder. A first terminal is coupled to a
first resistor of the resistor ladder. A second terminal is coupled to
the first resistor. A third terminal is coupled to a reference voltage. A
switch has a first state coupling the first terminal to the third
terminal and a second state coupling the second terminal to the third
terminal. A first analog-to-digital (A/D) converter is coupled to the
resistor ladder and the first receiver. The first A/D is configured to
compare a first voltage with a second voltage to determine if the switch
is positioned in the first state or the second state. A second
analog-to-digital (A/D) converter is coupled to the resistor ladder and
the second receiver and also configured to perform a voltage comparison.