通过网络(PJLink协议)来控制投影机。As the demand for Projectors/Displays increases with the popularization of personal computers, many manufacturers have branched out into Projector/Display markets. With the recent diversification of digital media and growth of IP networks, Projectors/Displays with a higher utility value, namely support for networks, are now on the market. Network-ready Projectors/Displays provide significant convenience for users: the constraints of placement location and distance are relaxed and it is possible to control and monitor more than one Projector/Display at once. However, the convenience can be impaired by differences among manufacturers in control system configuration and command type. Projector/Display control software provided by a specific manufacturer can be used only for Projectors/Displays manufactured by the same manufacturer and would be useless in a large-scale system where multiple Projectors/Displays with different control systems and command types are to be controlled/monitored simultaneously. Some users have independently developed very complicated control software.