The invention concerns an accessory (112) for coupling to a portable electronic device (110). The accessory includes an interface (120) for coupling to the portable electronic device, an identifier (124) in which the identifier generates at least in part a parameter and at least one speaker (128). Only if the accessory contains more than one speaker, the parameter generated at least in part by the identifier causes an audio amplifier (148) that drives one of the speakers to be activated. In addition, the parameter generated at least in part by the identifier can cause the audio amplifier to be deactivated if the accessory contains only one speaker.