Patent ID: 7917172

Claim:
An accessory for connection to an electrical interface of a portable electronic device, where the electrical interface comprises a pair of bias voltage providing connection points including a first connection point and a second connection point for biasing a signal providing element of the accessory, the accessory comprising: a set of electrical branches comprising at least a first electrical branch, the first electrical branch comprising: a first voltage dividing element, a first switch that is arranged to be actuated mechanically, a first end that connects to the first connection point in the pair of bias voltage providing connection points, and a second end that connects to the second connection point of the electrical interface to change a voltage level of the first connection point connected to the first end to a different voltage level when said first switch interconnects said first voltage dividing element and the first connection point; and a second electrical branch in the set of branches, the second electrical branch comprising: a second voltage dividing element, a second switch that is arranged to be actuated mechanically, and third and fourth ends that connect to the same connection points as the first and second ends of the first branch, where said second voltage dividing element changes the voltage level of the connection point connected to the third end to a voltage level that is different than voltage levels provided by other branches that connect to the connection point connected to the third end when said second switch interconnects said second voltage dividing element and the connection point connected to the third end.