A plurality of connections may be established between an accessory interface and a plurality of accessories. A connection between the accessory interface and a portable electronic device may also be established. A first set of messages may be communicated via the accessory interface between the portable electronic device and a first accessory of the plurality of accessories. A second set of messages may be communicated via the accessory interface between the portable electronic device and a second accessory of the plurality of accessories. The first and second sets of messages communicated between the portable electronic device and the accessory interface may be formatted in accordance with a data exchange pattern.