Hitachi, Ltd.

Yagi Antenna Co., Ltd.

Hitachi Software Engineering Company, Ltd.

Yukio Nakata

Osamu Shiotsu

Kaoru Suda

Motoyoshi Morito

Yukio Shimamoto

Atsushi Kobayashi

Yasuhiro Takahashi

Akira Nakajima

Hidemitsu Higuchi

Susumu Matsui

Takeshi Kondo

Keiichi Nakane

Masato Arai

Hiromichi Ito

Satoru Tezuka

Matsuaki Terada

Kenji Nakamura

Tetsuji Takegoshi

Takeshi Kondou

Kenichi Hironaka

Yuuji Aoyagi

Takeo Honma

Yutaka Otsu

Tomohiko Yanagita

Katsuhiro Ono

Mitsuru Mori

Toshiya Ito

Tomio Sato

Katsumi Imaizumi

Nobuyuki Tottori

Daiji Hitaka

Syoji Yokoyama

Junichi Matsumoto

A mobile computer supporting system realizes communication even when a communication protocol address is to be dynamically changed due to movement of the computer, or the like. When a PC has moved, it notifies an AMS of a changed present address together with its home address. The AMS stores the home address and present address of each terminal, so as to correspond to each other, into an address correspondence table. When a PC sends and receives information to and from the PC, a socket hook processing of the PC acquires the information when the home address of the PC is added to the information. The socket hook processing inquires of the AMS of the present address of the PC using the home address of the PC, converts the home address of the PC added with the information to the present address obtained by the inquiry, and sends the information after conversion to a socket processing.

Mobile computer supporting system, its administrative server, its

Data is compressed/encrypted for communication between application programs without addition of any modification to the application programs. In a communication system where a plurality of personal computers are connected to each other using communication lines, a personal computer is provided with a communication program and an application program, the application program uses a command offered by the communication program for transmission and reception of data with another personal computer, a hooking program for discriminating the command related to the data communication issued by the application program is provided and, after the hooking program has compressed or encrypted the data of application program depending on a type of the command, the command is transferred to the communication program.

Communication system

There is provided an information processing system in which files on plural file servers having different file management manners can be efficiently accessed by a single client program, a control method for the information processing system, and a storage medium for storing programs for performing the control. A gateway program 20 is provided on a first server information processing device 120, and an agent program 30 which is operated in conformity with the gateway program 20 is provided on a second server information processing device 130, whereby a copy of the directory structure of files on the second server information processing device is created on the first server information processing device 120. In addition, at the time when the copy is created, data in a file are not copied, and the data copy is performed only when the file is opened by an application program 8a of a client information processing device 110.

Information processing system enabling access to different types of

A distributed information processing system which includes a server having a resume-request processor and clients having resume-request units or processor. An user at the client site operates a resume switch to save an operation state of the client in the server's magnetic disc, and resume it from the server's magnetic disc. The operation state includes contents of the main memory, contents of the display memory, values of the I/O registers for peripheral devices, and information about the file of the server being used by the application program run by the user. The user is able to use any client of the system in the same situation including a connection state between the file and the application program as before.

Distributed information processing system providing a resume function

A multi-protocol communication control apparatus which includes a plurality of kinds of upper layer protocol controllers, a plurality of kinds of lower layer protocol controllers, and a common interface controller for processing correspondence between the upper and lower layer protocols controllers. The multi-protocol communication control apparatus provides for the optional use of any combination of a plurality of kinds of upper layer communication protocols, a plurality of kinds of lower layer communication protocols, and a plurality of transmission lines.

Multi-protocol communication control apparatus

A data transfer system for transferring data among plural terminals which are connected through a transmission line. each terminal capable of performing distributed processing and includes an unit for delivering on the line a first signal having an identification information of a user who utilizes the terminal and an identification information of the terminal and a unit for delivering on the line a second signal having an identification information of a destination user to which data is to be transferred as an identification information of the terminal which is a delivery source of the data. At least one of the terminals includes a memory for receiving the first signal on the line and for storing the identification information of the user and the identification information of the terminal of the first signal in a manner that history of the received identification information of the terminal is stored for each of the identifications of the users, and an unit for receiving the second signal on the line, for searching said memory on the basis of the identification information of the destination user of the second signal to read out a newest one of the stored identification information of the terminal associated with the received identification information of the user of the second signal and for delivering on the line a third signal having the read identification information and the identification information of the second signal.

Designated mail delivery system

A thermal transfer printer has a platen and a thermal head between which are pinched a transfer paper sheet and an ink film, so that the ink is transferred from the ink film to the transfer paper sheet as heat is applied to the transfer paper sheet by the thermal head. The film is supplied by a supply roll and is taken-up by a take-up roll. The thermal head is swingable between a position where it contracts the platen and a position away from the platen. When the thermal head is in the position away from the platen, the distance therebetween is greater than the maximum diameter of the supply roll. A film drum can hold a plurality of films each being constituted by the supply roll and the take-up roll. Swing arms are provided for demounting the supply roll of a selected film from the film drum and for bringing the same to a position away from the film drum, and also for returning the same from this position to the film drum. During the movement of the supply roll between the position in the film drum and the position away from this position, the thermal head is moved away from the platen so as not to hinder the movement of the supply roll.

Thermal transfer printer

In a data signal demodulating circuit for demodulating data from a modulated signal burst in which a carrier signal is modulated by a data signal, noise elimination means is provided at at least one of the input and output of an AND circuit, to eliminate noise in periods during which there is no carrier present, by adding an output from a demodulator to an output from a carrier sense circuit, in order to completely eliminate noise occurring at the start and end of a demodulated data signal, and eliminate noise occurring during the rise time and fall time of the carrier sense circuit.

Demodulating circuit for data signal

In this data communication system, data communication is conducted through transmission lines between a plurality of stations. At each station, the presence of data to be sent is detected, the length of the detected data is measured, and that that station is disconnected from the transmission lines when the length of data exceeds a predetermined value, to inhibit the sending of data from that station.

Method and device for data communication

A method for data communication usable for a system having a common transmission line, a plurality of transceivers connected to the common transmission line, and a data processing equipment connected to each of the transceivers, the system being arranged such that data from the data processing equipment is sent to the common transmission line through the corresponding transceiver, while data from the common transmission line is sent to the data processing equipment through the corresponding transceiver, thereby effecting a data communication between data processing equipment, wherein when a request to send data is sent from the data processing equipment to the corresponding transceiver, a carrier signal is sent to the common transmission line, and when the fact that no data is sent from any of the other transceivers to the common transmission line is detected during a given period of time after the sending of the carrier signal, the transceiver gives a permission to send data, to the corresponding data processing equipment, which then sends data on the permission. Also disclosed is a device for carrying out the above-mentioned method for data communication.

In a data communication system which has a common transmission line, a plurality of transceivers connected to the transmission line and data processors connected to the respective transceivers, and in which data from the data processor is delivered to the common transmission line through the corresponding transceiver, and data from the common transmission line is delivered to the data processor through the transceiver, so as to perform data communications among the data processors; a data communication system wherein said each transceiver comprises a first circuit which checks if an address of the data received from the transmission line has been received without any transmission error, a second circuit which checks if the address is one directed to the particular transceiver when the absence of the transmission error has been decided by the first circuit, a third circuit which turns back and delivers the received data when the address directed to the particular transceiver has been decided by the second circuit, and a fourth circuit which compares the sent data with the data turned back from another transceiver, the sending of the data being stopped when disagreement has been detected by the fourth circuit.

Data communication system with error detection/correction

A system for frequency modulation which generates first and second signals having different frequencies in a switching manner in accordance with the logical value of an input signal. The system includes an oscillator for generating a signal having a predetermined frequency; first and second frequency-dividers for subjecting the signal generated by the oscillator to frequency division by different integers l and m to generate first and second signals which are synchronized with each other; a third frequency-divider for subjecting an output signal from said second frequency-divider to frequency division by an integer n selected so that the product m.times.n is the least common multiple of l and m; a control device for controlling input data with an output signal from said third frequency-divider; and a switching device for selecting one of the output signals from the first and second frequency-dividers in accordance with the logical value of an output signal from the control device to generate an output which is passed through a filter for providing a modulated output.

System for frequency modulation

A data communication system including reflectors having first light emitting elements for radiating light and first light receiving elements for receiving light, a plurality of transceivers disposed confronting said reflectors and having second light emitting elements for radiating light and second light receiving elements for receiving light, and a data processing unit to be connected to the transceivers, wherein light corresponding to the data to be transmitted from the data processing unit is converged and radiated from the second light emitting element of the transceiver to the reflector, the light from the transceiver is received by the first light receiving element of the reflector, light corresponding to the data thus received is radiated from the light emitting element of the reflector to all of the transceivers confronting said reflector and is received by the second light receiving elements of the transceivers, and the data thus received is sent to the data processing unit.

Growing community of inventors

Kawasaki, Japan

Yukio Nakata