To provide a system which allows large volumes of data to be exchanged efficiently through network connections using portable terminals. An example data communications system includes a data terminal which stores certain data; and an operation terminal which controls access rights to the data stored in the data terminal, in which the operation terminal grants another operation terminal access rights to desired data. The data terminal returns the data according to an access request made based on the access rights. On the other hand, the operation terminal passes the acquired access rights to the data terminal, which then accesses the data terminal via a high-speed, stable, wired network and acquires the desired data, based on the access rights.