To solve the problems that it is difficult to appropriately link a peripheral machine to a printing machine even when sheets can be mechanically delivered when there is not a direct electric interface between the printing machine such as a printer or a digital composite machine and the peripheral machine such as a feeder, a stacker or a finisher that is the pre/post processing device, and it is impossible to freely link various peripheral machines to the printing machine since generally specifications are different for each maker even when there is an electric interface.

By providing a monitor control part capable of communicating with each of the printing machine and the peripheral machine independently by a general purpose interface, print information and abnormality information, etc., are acquired from both, monitored or appropriately transmitted to both indirectly. Thus, the printing machine and the peripheral machine are connected on line in a pseudo manner even without a direct electric interface and the machines are linked.