Circuits, methods, and apparatus that provide compatibility among incompatible accessories and portable media players. One example provides an adapter having a connector receptacle to mate with an accessory's connector insert and a connector insert to mate with a portable media player's connector receptacle. Another example provides an adapter having a direct connection between pins on the connector insert and pins on the connector receptacle that are used for compatible signals. Another example provides an adapter including a DC-to-DC converter that receives a first power supply from an accessory and provides a second power supply to a portable media player. Another translates signals using different signaling technologies. Authentication and identification circuitry may also be included. Other examples may employ wireless technologies instead of either or both the connector insert and connector receptacle.