The relationship between sending device and receiving device is controlled with a high degree of freedom when sending and receiving data between multiple devices.A POS system has a second tablet terminal that receives data, and a host device. The host device has a server interface that sends data to the second tablet terminal; a storage unit that includes a transmission buffer for storing data and stores buffer link information relating the transmission buffer to the second tablet terminal to which the data is sent; and a communication unit 2 that acquires data and control storing the data to the transmission buffer. When the communication unit stores the data to the transmission buffer, the stored data is sent to the second tablet terminal.