Hitachi, Ltd.

Hitachi Process Computer Engineering, Inc.

Other

Hitachi Cable, Inc.

Hitachi Information Control Systems, Inc.

Toshiyuki Murakami

Yutaka Sato

Sadao Mizokawa

Hisayuki Maruyama

Masato Satake

Seiichi Yasumoto

Junji Fukuzawa

Hisao Ogawa

Ken Onuki

Toshihiko Uchiyama

Osamu Anbo

Naoki Ogawa

Masahiro Nagasu

Norihiko Sugimoto

Shigenobu Yanai

Keiji Ishida

Naomasa Hanano

Masanori Kogawa

A high reliability information transmission system which can continue transmission upon at the occurrence of multiple failures. The system includes two transmission lines and transmission terminals coupled to both of the transmission lines. Data can be transmitted between respective terminals using both transmission lines. The transmission terminals check the data reception status at the corresponding receiving terminals. When data is not being received, the data may be relayed to the receiving terminal using one of the other transmission lines.

Information transmission system and information transmission method

A data transmission method and system of a token passing type capable of periodically transmitting cyclic data produced in a station to other stations while enabling a packet data communication with high efficiency and without disturbing the periodicity of the cyclic communication. A token circulation time is set to be shorter than a cycle time for production of the cyclic data where no packet data to be transmitted. Also each station will pass an acquired token immediately to the next station if the station has no data to be transmitted. Thus, at least one station can have a token at least two times during the cycle time to transmit the cyclic data and the packet data. Upper limits may be set to capacities of the cyclic data and the packet data which are capable of being transmitted each time the token is acquired.

Data transmission method and system thereof

A data transmission method and system of a token passing type capable of periodically transmitting cyclic data produced in a station to other stations while enabling a packet data communication with high efficiency and without disturbing the periodicity of the cyclic communication. A token circulation time is set to be shorter than a cycle time for production of the cyclic data where no packet data is to be transmitted. Also each station will pass an acquired token immediately to the next station if the station has no data to be transmitted. Thus, at least one station can receives a token at least two times during the cycle time to transmit the cyclic data and the packet data. Upper limits may be set to capacities of the cyclic data and the packet data which are capable of being transmitted each time the token is acquired.

Transmission method and system thereof

A signal transmission system comprising an apparatus which inhibits the repeating in the opposite direction during reception and transmission of frames and which monitors the number of frames which were outputted in one direction from a repeater and the number of frames which were returned from such direction, whereby a destruction and circulation of the frame are inhibited without reducing response speed of a signal.

Signal transmission system having a star coupled repeater

In each node accommodated in a token-ring network system, a storage unit for storing priority levels is constituted by a plurality of flip-flops which provide bit positions of the same number as that of grades of the priority level. When storing a value of priority level which is higher than a value of priority level stored in the storage unit, the corresponding flip-flop of the storage unit is set. Two priority encoders connected to the output of the storage unit detect, from data of priority level stored in the storage unit, first and second priority levels and load then on registers, respectively. In accordance with the contents of the registers, the corresponding flip-flop of the storage unit is rest, when each node detects a value of priority level stored in the storage unit.

Method of and apparatus for storing priority levels in token-ring

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Hitachi, Japan

Toshiyuki Murakami