Abstract: The invention implements inter-terminal transmission with guaranteed capacity based on the single-path configuration function of networks composed of switching hubs with an MAC address learning function and centralized management of transmission capacity, without control over hubs. The capacity to be used by transmission links on a network is stored in advance and transmission capacity along the path to be used is allocated based on requests from terminals, with the allocation removed using a Terminate Request. At such time, by using transmission links and switching hubs with an MAC address learning function, transmission is limited to single-path transmission.

Abstract: It is provided switching means for connecting and disconnecting a link between nodes, so that when a network has a redundant link which forms a loop among nodes—this loop preventing normal connection relationship being maintained—the connection relationship can be made normal by controlling this switching means. Controlling the switching means also achieves rapid recovery from a fault which has occurred in a link between nodes, by utilizing the aforementioned loop to form a route that bypasses the fault.

Abstract: A loop-back recovery technique used when a failure takes place in a ring network, for transmitting information to a path indicated with a path ID number or the time slot position from a periodic frame. This is achieved by establishing working paths on one of the dual ring line between a transmission node and a receiving node thereof, establishing ring-formed protection paths in a ring line of the direction opposite to the working line, and making a loop-back from the working paths to the corresponding protection paths at a node which detected the failure. The receiving node multiplexes the working and protection paths to receive data from either.

Abstract: Bothway optical communication is carried out through a wavelength division multiplex system between two terminal stations (11a, 12a), each having a two-beam interference type filter (15) coupled with an optical cable (10) for multiplexing and/or de-multiplexing transmitted light and received light. The filter (15) has passbands and attenuation bands having periodic characteristics for the wavelength in the communication wavelength band. The wavelength of the transmitted light is essentially the same as the wavelength of the received light in each terminal station, with a small offset of the two wavelengths less than 5 nm. The oscillation wavelength of the laser (21) for transmission is adjusted so that it coincides with the passband of the filter, which doubles as a reference wavelength of the oscillation wavelength of the laser.

Abstract: Packet transfer is controlled by using an acceleration rate of packet transfers or by using a packet transfer rate acceleration ratio to predict that congestion will occur at a prescribed time in the future. Congestion avoidance in packet integrated networks is thereby achieved in a network having both variable rate terminal nodes and fixed rate terminal nodes. A future packet transfer rate is predicted in a congestion prediction circuit on the basis of a pre-established upper limit for the packet transfer acceleration or acceleration ratio. When it is predicted that the packet transfer rate will exceed a permissible value, a congestion prediction signal is output or a rate increase request indication is deleted. The invention prevents packets from being discarded in the packet network, allows buffer memory capacity of nodes in the network to be decreased, and avoids the generation of new packets when signal congestion is predicted.

Abstract: A process for producing an aromatic acylation product from an aromatic compound, an olefin and carbon monoxide, which comprises the steps of:(a) reacting an olefin with carbon monoxide in the presence of hydrogen fluoride and boron trifluoride at a pressure of not more than 100 kg/cm.sup.

Abstract: In a secure transmission system in which first and second pieces of communication equipment are interconnected via a transmission line, the first communication equipment has a conversion part for encrypting an information signal to be transmitted, through utilization of a received signal and the second communication equipment has an information memory for storing, as a key information, information to be transmitted to the first communication equipment and an inverse conversion part in which the encrypted signal received from the first communication equipment is decoded using the key information read out of the information memory. As the transmission information signal varies, the key information also varies accordingly. Hence, a highly secure transmission system and secure communication equipment can be realized.

Abstract: A process for manufacturing high-purity o-toluic acid from a partial oxidation product of o-xylene is disclosed. o-Toluic acid is widely used as a raw material for agricultural chemicals, medicines, polymerization initiators, and the like. Depending on its use, 99% by weight or more purity is demanded for o-toluic acid. Hitherto, o-toluic acid having purity of higher than 99% by weight could not be obtained by fractionation, and purification by fractional crystallization was used. Fractional crystallization is, however, and expensive operation and not only gives a low yield of product but also results a large amount of waste water. The process disclosed herein gives an economical, commercial way to obtain high purity o-toluic acid.

Abstract: The present invention relates to a process for decomposing an aromatic acylated compound.HF-BF.sub.3 complex in preparing an aromatic acylated compound by decomposing an aromatic acylated compound.HF-BF.sub.3 complex obtained by reacting an aromatic compound with an acylating agent in the presence of HF-BF.sub.3 as a catalyst, which comprises subjecting the aromatic acylated compound.HF-BF.sub.3 complex to thermal decomposition in the presence of at least one aromatic hydrocarbon (A.H.) selected from benzene, toluene and chlorobenzene and at least one saturated aliphatic hydrocarbon (S.H.) selected from pentane, hexane and cyclohexane, as a decomposing agent.

Abstract: In an apparatus for receiving a burst signal intensity-modulated by a signal obtained by Manchester-code converting each code of an input signal into a pair of codes, the received burst signal is converted by a partial response circuit into an AC signal and then AC-amplified. From the received burst signal is extracted a timing signal of the same frequency as the clock frequency of the Manchester-coded signal. In a decision circuit, the AC-amplified output is decided by the timing signal, through using a decision level close to zero, at the timing of each of former and latter codes of the Manchester-coded pair codes. A coding rule violation is detected in a plurality of successive decision output codes to detect a reception abnormality such as asynchronism and a signal collision. The decision output is decided at the timing of the latter one of the Manchester-coded pair codes, thereby regenerating transmitted information.