A communication system has a controller for transmitting data to be played back by a plurality of playback devices corresponding to a plurality of channels, and a plurality of adapters required for executing playback by the playback devices. The controller has a setting unit which sets data to be played back by the playback devices and control information required to control playback of the data in time slots of a sync transmission frame, and a transmission unit which transmits the sync transmission frame the by the setting unit to the adapters. Each adapter has a reception unit which receives the transmitted sync transmission frame, and a playback control unit which extracts data corresponding to the channel to be played back by the adapter from the sync transmission frame, and controls the playback timing of the data based on control information corresponding to the data.