To improve the cost performance of a multi-function peripheral system for an efficient communication function.
A data processing system of the system is provided with a multi-function peripheral device 110a that has a display device 225, a user entry device 230, a processor 260, a RAM, a ROM, a communication interface 220, and a hard output function which receives a document and scans the document, and also with a host device 110b that has a communication channel 290 connecting to the communication interface, a processor 255, a RAM, a ROM, a communication interface 205 and a network adaptor 210 which makes communication with a computer network. The host device prepares contents and headers depending on transfer data and assembles a data packet by combining them and transmits the packet to the multi-function peripheral device through the communication channel.