A communication system includes: a communication device; and a data receiver that is configured so as to be capable of being connected to the communication device. The communication device includes: a content summary receiving unit that is configured so as to be capable of receiving content summary data transmitted from an external device, the content summary data including at least positional data and title data for content data; and a positional data transmitting unit. The data receiver includes a scheduled port querying unit that is configured to transmit to the communication device a query querying the communication device for a scheduled port. The communication device further includes: a scheduled port notifying unit that, upon receiving the scheduled port query from the data receiver, transmits to the data receiver a scheduled port notification indicating the scheduled port. The data receiver further includes: a determining unit that determines whether the scheduled port indicated in the scheduled port notification is available; and an availability notifying unit that transmits to the communication device an availability notification indicating the scheduled port that is determined as being available. The communication device further includes: an active port setting unit that sets the scheduled port indicated by the availability notification as an active port; and an active port notifying unit that transmits to the data receiver an active port notification indicating the active port. The positional data transmitting unit transmits the positional data for the content data to the data receiver through the active port at a prescribed timing and according to the prescribed communication protocol.