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1. 发明专利

JPH04298199A CLOCK SUPPLY DEVICE AND COMMUNICATION NETWORK SYSTEM 失效
公开(公告)号：JPH04298199A
公开(公告)日：1992-10-21
申请号：JP6336191
申请日：1991-03-27
申请人： HITACHI LTD , HITACHI CABLE
发明人： MARUYAMA HISAYUKI , MABUCHI HIROSHI , MIZOKAWA SADAO , TOMIZAWA HIROSHI
IPC分类号： H04L7/00 , G06F1/06 , H04Q11/04
摘要： PURPOSE:To switch a clock supply system while a self-running clock of a PLL is latched. CONSTITUTION:The system is provided with clock selection means 52 selecting a clock from clock supply systems 22, 26, a multiplier means 56 multiplying a frequency of an input clock selected by the clock selection means 52, fault detection means 70, 72 monitoring a generating state of the clock selected by the clock selection means 52 based on an output clock of the multiplier means 56 and detecting the occurrence of a fault in the input clock based on the result of monitor, a changeover means 74 outputting a switching signal to the clock selection means 52 by the detection output of the fault detection means 70, 72, and a PLL provided with a D-T flip-flop 58, a loop filter 64, a voltage controlled oscillator 66 and a frequency divider 68 is used for the multiplier means 56 and the clock is selected while the self-running clock of the PLL is latched.

2. 发明专利

JPH0447827A ABNORMAL DATA COMMUNICATING PREVENTING SYSTEM FOR LOOP NETWORK 失效
公开(公告)号：JPH0447827A
公开(公告)日：1992-02-18
申请号：JP15671690
申请日：1990-06-15
申请人： HITACHI CABLE , HITACHI LTD
发明人： KURIYAMA MASARU , HAYAMA HIROYUKI , TOMIZAWA HIROSHI
IPC分类号： H04L12/42
摘要： PURPOSE:To prevent an abnormal data from flowing to a terminal by stopping transmitting a data received from a channel to the terminal by each node executing fully duplex communication in the case of generating abnormality in the node connected to the terminal as a communicating party. CONSTITUTION:Assuming that a node 1d on a terminal A side breaks down, a monitoring cycle is not t1 for a bit monitoring part 65 for monitoring a node 1b on a terminal B side. Assuming that the bit monitoring part 65 for monitor turns the output to '1'. Consequently, the output to the terminal B at a reception part 64 of the node 1b is turned to a Mark state ('1' at all times), and the transmission of the data received from the channel to the terminal B is stopped. Thus, at the terminal B, the data transmitted by the terminal itself is not returned as it is. Similarly, even when the abnormality is generated at the node 1b, the output is turned to '1' and the output to the terminal A is turned to the Mark state. Therefore, for the terminal A, the data transmitted by the terminal itself is not returned as it is.

3. 发明专利

JPH0368236A SYSTEM FOR PREVENTING ABNORMAL DATA COMMUNICATION IN LOOP NETWORK 失效
公开(公告)号：JPH0368236A
公开(公告)日：1991-03-25
申请号：JP20286389
申请日：1989-08-07
申请人： HITACHI CABLE , HITACHI LTD
发明人： HAYAMA HIROYUKI , TOMIZAWA HIROSHI
IPC分类号： H04L12/42
摘要： PURPOSE:To prevent abnormal data communication to a receiving terminal by providing a one-bit area for monitor in a channel and quickly detecting abnormality in a node at the receiving terminal side in case of the occurrence of the abnormality in a node on the transmitting terminal side. CONSTITUTION:At the time of sending data from a terminal A to a terminal B, a bit transmitting part 52 for monitor transmits a signal, which is repeatedly turned on and off at intervals of a certain time, to a bit 23 for monitor in the channel during data transmission. A bit non-change detecting part 55 for monitor in a receiving part 54 monitors contents of the received bit 23 and sets the detected output to '0' during the change of turning-on/off, and the detected output is set to '1' when the change of turning-on/off is not detected for a certain time or longer. That is, the output of the detecting part 55 is set to '1' and the output to the terminal B is set to the mark state when the bit 23 is not turned on/off because of the occurrence of abnormality in the node. Thus, abnormal data in the channel is prevented from flowing to the terminal B to improve the reliability of a system.

4. 发明专利

JPH03114330A LOOP TRANSMISSION SYSTEM 失效
公开(公告)号：JPH03114330A
公开(公告)日：1991-05-15
申请号：JP25053389
申请日：1989-09-28
申请人： HITACHI LTD , HITACHI CABLE
发明人： SUGIMOTO NORIHIKO , YONEDA KATSUHIKO , OKADA MASAKAZU , TOMIZAWA HIROSHI , OGAWA HISAO , MURAMOTO TORU , YASUMOTO SEIICHI , KOYAMA YUKIO
IPC分类号： H04L12/42
摘要： PURPOSE:To inhibit the reception of a cyclic data due to transmission abnormality by providing a channel header to revise decision. CONSTITUTION:Each of channels C1-Cl constituting a frame transmitted on a transmission line is constituted of a channel header CH and an information part I, and the channel header CH includes a parity bit P, a station identification code D, a monitoring bit M and an information valid bit V. Then a reception station decides normality of the information part from the content of the channel header CH set by a transmission station and the information valid bit V is revised into a reset state in case of the abnormal data. Thus, the circulation data due to transmission abnormality is not received.

5. 发明专利

JPH03114331A CIRCULAR COMMUNICATION METHOD 失效
公开(公告)号：JPH03114331A
公开(公告)日：1991-05-15
申请号：JP25053489
申请日：1989-09-28
申请人： HITACHI LTD , HITACHI CABLE
发明人： SUGIMOTO NORIHIKO , YONEDA KATSUHIKO , OKADA MASAKAZU , TOMIZAWA HIROSHI , FUJIEDA SHUICHI
IPC分类号： H04L12/42
摘要： PURPOSE:To execute various communication formats between terminal equipments connected to an arbitrary station by enabling transmission/reception even when plural terminal equipments of 1:n multi-drop connection are connected to one and the same station. CONSTITUTION:Stations S1-S6 are connected in the order shown in figure to a circular transmission line 1 and terminal equipments are connected to respective stations and 2 terminal equipments T1, T2 are connected to the station S1. There is not limit in the connection number of terminal equipments and the stations S1-S6 are constituted similarly. In the case of plural slave terminal equipments in 1:n multi-drop connection to one and the same station, the reception of a same data to plural terminal equipments and the transmission to one terminal equipment among the plural terminal equipments are enabled. Thus, the circular communication method in which various communication formats are realized between terminal equipments connected to an arbitrary station is realized.

6. 发明专利

JPH03266545A ELIMINATION SYSTEM FOR NOISE SOUND DUE TO VOICE DATA ERROR IN INSIDE OF LAN 失效
公开(公告)号：JPH03266545A
公开(公告)日：1991-11-27
申请号：JP6427590
申请日：1990-03-16
申请人： HITACHI CABLE , HITACHI LTD
发明人： IKENOBE MASAKI , TOMIZAWA HIROSHI , FUJIEDA SHUICHI
IPC分类号： H04L1/00 , H04B14/04 , H04L12/28
摘要： PURPOSE:To prevent noise sound from being sent to a voice terminal equipment by outputting a correct data just before occurrence of an error from an interface board in place of an erroneous data. CONSTITUTION:A parity check device 13 checks the presence of an error as to a digital data sent from a node inside 11 at a predetermined period through a digital data transmission line 12 and the result is informed to a control circuit 15 through a parity error signal line 14. The control circuit 15 based on the result outputs a control signal 16 to a transmission changeover circuit 18 and a buffer 17. When an error takes place, the transmission changeover circuit 18 aborts the error data and outputs a just preceding data from the buffer 17 to a D/A converter 19 and the voice analog signal 20 is sent to a voice terminal equipment 23. Thus, output of a noise sound is prevented to the voice terminal equipment 23.

7. 发明专利

DE3267151D1 LOOP TYPE DATA HIGHWAY SYSTEM 未知
公开(公告)号：DE3267151D1
公开(公告)日：1985-12-05
申请号：DE3267151
申请日：1982-07-05
申请人： HITACHI LTD
发明人： MIZOKAWA SADAO , HAMADA TAKUJI , TOMIZAWA HIROSHI , FUSHIMI HITOSHI
IPC分类号： G06F13/00 , H04L12/433 , H04L11/16
摘要： A loop type data highway system in which a plurality of data transmission control stations (abbreviated herein as stations) are connected in cascade to a loop transmission line. Each of the stations responds to a polling frame inquiring of request for reservation of the transmission line. The polling frame is composed of a first field for inquiring of the line reservation request and a second field indicative of whether the line is reserved or not. Each station receives signals inputted from the upstream side along the line and sequentially repeats them to the downstream side along the line without delay. In the station having the line reservation requests, a pattern representative of the line reservation is written in the second field after reception of the first field and sends out the polling frame to the downstream. When the second field as received indicates the non-reserved state of the transmission line, transmission of data is initiated in succession to the second field.

8. 发明专利

JP2002044113A HUB DEVICE 失效
公开(公告)号：JP2002044113A
公开(公告)日：2002-02-08
申请号：JP2000219686
申请日：2000-07-19
申请人： HITACHI LTD , HITACHI INF & CONTROL SYST
发明人： WATANABE SHIZUYA , TOMIZAWA HIROSHI , NITTA MAKOTO
IPC分类号： H04L12/44
摘要： PROBLEM TO BE SOLVED: To provide a hub device that can diagnose the occurrence of a fault from the reception processing to the transmission processing of the hub device even during execution of on-line communication without deteriorating the real time performance of communication data. SOLUTION: The hub device is provided with a data transmission reception processing device 13 that receives data from stations 3, adds a diagnostic signal to a gap time between the received data to process the received data and to control a transmission destination. The hub device detects the diagnostic data from the data sent from the data transmission reception processing device 13, discriminates whether or not the diagnosis is finished and discriminates it as the occurrence of a fault when the diagnostic signal is transmitted but no completion of the diagnosis is detected.

9. 发明专利

JP2002016664A LOOPBACK TEST METHOD AND DEVICE 失效
公开(公告)号：JP2002016664A
公开(公告)日：2002-01-18
申请号：JP2000197886
申请日：2000-06-27
申请人： HITACHI LTD
发明人： YAMATANI SHOGO , WATANABE SHIZUYA , TOMIZAWA HIROSHI
IPC分类号： G06F11/22 , G06F13/00 , H04L29/14
摘要： PROBLEM TO BE SOLVED: To provide a loopback test method that can be executed online. SOLUTION: In a system that is provided with computers 11, 12,..., each having a loopback test function and a line concentration device (HUB) 31 having ports 1, 2, etc., connected to the computers through a twisted pair cable 21 having a transmission line 211 and a reception line 212, each port has an SW1 that connects the transmission line and the reception line, and a communication control section 3111 that issues a test request in the absence of transmission reception data from a computer connected to itself and other ports, the SW1 is connected when receiving an ACK from the computer to conduct a test from the computer. The HUB 31 has a buffer that temporarily stores data received from the other port during the test.

10. 发明专利

JP2000099358A CYCLIC COMMUNICATION SYSTEM 失效
公开(公告)号：JP2000099358A
公开(公告)日：2000-04-07
申请号：JP27093798
申请日：1998-09-25
申请人： HITACHI LTD
发明人： WATANABE SHIZUYA , TOMIZAWA HIROSHI
IPC分类号： G06F11/20 , G06F15/167 , H04L12/24 , H04L12/26 , H04L12/40
摘要： PROBLEM TO BE SOLVED: To attain improvement in the reliability of cyclic transmission switching to a slave system in the case of master system fault by providing a mechanism for switching the setting area of a shared memory at another station to a transmission area, reception area or transmission/reception stop area. SOLUTION: A shared memory 6 writes/reads data from a host computer 4 of a present station 2 or writes data received from another station 2. A table 7 for transmission/reception setting stores the setting information of transmission area, reception area and transmission/reception stop area for each block of the shared memory 6. In this case, transmission/reception setting information is added for controlling the data transmission/reception operation of the other station 2 to transmission data by the instruction of the host computer 4 so as to transmit data to the shared memory area set to the transmission area by the other station 2. At the station to receive the data to which this transmission/reception setting information is added, this information is fetched and the data transmission/reception operation of the present station 2 is changed.

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