Abstract: A system for transmitting data in high precision by restricting a delay in data transmission time includes a hub. The hub receives through the transmission media a data frame transmitted from a communication device that has a transmission request among a plurality of communication devices, and relays the received data frame to a destination communication device based on a destination address included in the received data frame.

Abstract: A system for transmitting data in high precision by restricting a delay in data transmission time, and including a hub. The hub receives through transmission media a data frame transmitted from a communication device that has a transmission request among a plurality of communication devices, and relays the received data frame to a destination communication device based on a destination address included in the received data frame.

Abstract: In an annular transmitting system including a ring-like transmission path realized by interconnecting serially a plurality of transmission stations in an annular form, at least one of the transmissions stations generating repetitively a transmitting frame constituted by a plurality of transmission units referred to as time slots, the frame being circulated along the transmission path, wherein transmission of information among transmission stations is performed in such a manner in which each of the transmission stations having a request to send information inserts the information in the slots by dividing the information, which information is ultimately fetched by the transmission station destined to receive that information, a multi-slot access system in which each of the time slots is provided with an area indicating whether the associated time slot is "free" or "busy", wherein the transmission station having a request to send information determines that the sending of the information is enabled when it is de

Abstract: A ring network data transmission system includes a plurality of transmission apparatuses, at least one terminal connected to each of the transmission apparatuses and double ring transmission paths interconnecting the transmission apparatuses in a ring-like system configuration so that terminals can communicate with one another through the associated transmission apparatuses. When a transmission fault occurs in the network, the transmission apparatus which can serve as the master station issues to all of the other transmission apparatuses a command for searching the fault location. In response to the reception of the command, each of the other transmission apparatuses sends out a monitor signal containing its own address and at the same time checks monitor signal received.