The present invention discloses an improved insert machine for inserting flat material into an open pocket and, more particularly, to a straight line insert machine employed for printed matter such as newspapers. The machine includes an all-electronic control system for controlling machine functions. The control system includes at least one central control computer running under software control and a plurality of network controllers, all coupled together via a controller area network (CAN) bus. Electronic control messages for controlling machine elements are sent among the computers and controllers using a novel message protocol to enable both broadcast messages and individual messages to be employed.