JPH0159780B2 - - Google Patents
Info
- Publication number
- JPH0159780B2 JPH0159780B2 JP55174384A JP17438480A JPH0159780B2 JP H0159780 B2 JPH0159780 B2 JP H0159780B2 JP 55174384 A JP55174384 A JP 55174384A JP 17438480 A JP17438480 A JP 17438480A JP H0159780 B2 JPH0159780 B2 JP H0159780B2
- Authority
- JP
- Japan
- Prior art keywords
- station
- monitored
- command
- return
- address
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000005540 biological transmission Effects 0.000 claims description 49
- 238000012544 monitoring process Methods 0.000 claims description 48
- 238000000034 method Methods 0.000 claims description 14
- 238000010586 diagram Methods 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 3
- 230000000737 periodic effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/42—Loop networks
- H04L12/437—Ring fault isolation or reconfiguration
Description
【発明の詳細な説明】
本発明は、二重化ループ伝送網において両系回
線障害時にループを再構成する方式に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reconfiguring a loop in a duplex loop transmission network when both lines fail.
以下に二重化ループ伝送網について説明する。
第１図は二重化ループ伝送網の概念図である。本
図において、１は現用系、１′は予備系伝送路、
２は監視局、Ａ〜Ｄは被監視局である。 The duplex loop transmission network will be explained below.
FIG. 1 is a conceptual diagram of a duplex loop transmission network. In this figure, 1 is the active transmission line, 1' is the protection transmission line,
2 is a monitoring station, and A to D are monitored stations.
ループ伝送網において、監視局２及び複数の被
監視局Ａ〜Ｄをループ状に接続する伝送路１，
１′および各局内の信号通路は、全局が共用する
ものであり、それらの障害は全システムのダウン
に直結する。そこで伝送路を第１図に示すように
二重化し、片系回線障害時における他系回線への
切替、あるいは両系回線障害時における局折り返
し機能を被監視局Ａ〜Ｄにおいて備えシステムの
稼動率、信頼性向上をはかつている。 In a loop transmission network, a transmission line 1 connects a monitoring station 2 and a plurality of monitored stations A to D in a loop;
1' and the signal paths within each station are shared by all stations, and any failure thereof will directly lead to the entire system going down. Therefore, the transmission line is duplicated as shown in Figure 1, and the monitored stations A to D are equipped with a function to switch to the other line in the event of a line failure in one line, or to return the station in the event of a line failure in both lines, increasing system availability. , improving reliability.
以下に二重化ループ伝送網における局折り返し
機能による従来の両系回線障害時ループ再構成の
方式を説明する。第２図は従来のループ再構成方
式の説明図である。本図においては１〜４の順に
ループの再構成が行なわれる。なお第１図と同一
番号は同一部位を示す。 A conventional method of loop reconfiguration in the event of a line failure in both systems using a station loopback function in a duplex loop transmission network will be described below. FIG. 2 is an explanatory diagram of a conventional loop reconfiguration method. In this figure, the loops are reconfigured in the order of 1 to 4. Note that the same numbers as in FIG. 1 indicate the same parts.
従来方式において監視局２は、システム起動時
に半固定的に設定された被監視局Ａ〜Ｄの局アド
レスと伝送路上の接続位置との対応を示すテーブ
ル、あるいは定期的なポーリングによつて得られ
たテーブルに従つて局折り返しを繰り返試行する
ことによつててループの再構成をはかる方法がと
られている。たとえば、第２図においてＸ印の点
で障害が発生したとすると、監視局２は、回線同
期はずれ、クロツク断等を検出し、前記のテーブ
ルを参照し監視局２に最も近い被監視局Ａに対し
監視信号を伝送路１を用いて送出し伝送路１′で
折り返し監視信号を送り返すことを命令する。 In the conventional system, the monitoring station 2 uses a table that shows the correspondence between the station addresses of the monitored stations A to D that are semi-fixed at the time of system startup and the connection positions on the transmission path, or the addresses are obtained by regular polling. The method used is to reconfigure the loop by repeatedly trying to return stations according to a table that has been set. For example, if a failure occurs at the point marked with an It sends out a monitoring signal using transmission line 1, and then sends back the monitoring signal via transmission line 1'.
この監視信号が正しく返送されると、次に近い
被監視局Ｂに対し監視信号を送出するが、第２図
においては被監視局ＡとＢの間の伝送路に障害が
あるので監視信号は返送されない。そこで監視局
２は被監視局Ａ，Ｂ間に障害があると判断し被監
視局Ａにおいて伝送路１の信号を伝送路１′へ折
り返す折り返し路を設定する。次に監視局２は監
視信号を伝送路１′へ送出し、被監視局Ｄ，Ｃ，
Ｂに対し上記と同様の操作を行ない、被監視局Ｂ
において折り返し路を設定し第２図４の如くルー
プが再構成される。 When this monitoring signal is returned correctly, the monitoring signal is sent to the next closest monitored station B, but in Figure 2, there is a failure in the transmission line between monitored stations A and B, so the monitoring signal is It will not be returned. Therefore, the monitoring station 2 determines that there is a fault between the monitored stations A and B, and sets a return path in the monitored station A to return the signal on the transmission line 1 to the transmission line 1'. Next, the monitoring station 2 sends a monitoring signal to the transmission line 1', and the monitored stations D, C,
Perform the same operation as above for station B, and
A return path is set at , and the loop is reconfigured as shown in FIG. 2.
ここで第３図１の様な障害が発生した場合を考
える。第３図１はループ伝送網における障害の一
例、２はループ再構成完了時における網構成であ
る。本図において破線で示した被監視局Ｃはバイ
パス路を設定しているものとする。なお、第１図
と同一番号は同一部位を示す。 Let us now consider the case where a failure as shown in FIG. 31 occurs. 3. FIG. 1 shows an example of a failure in a loop transmission network, and 2 shows the network configuration upon completion of loop reconfiguration. In this figure, it is assumed that the monitored station C indicated by a broken line has a bypass path set up. Note that the same numbers as in FIG. 1 indicate the same parts.
被監視局はそれぞれ自局内で障害を発見した時
には自局を伝送路より切離し、バイパス路を設定
するバイパス機能をもつ。したがつて第３図１に
示すように被監視局Ｃにおいてバイパス路が設定
され網構成が変わつている場合、監視局２におい
て半固定的に設定されたテーブルはもとより、定
期ポーリングによつて得たテーブルの内容もポー
リング時と障害発生時との時間のずれにより障害
発生時点の網構成と一致しない。 Each monitored station has a bypass function that disconnects the station from the transmission path and establishes a bypass path when a failure is discovered within the station. Therefore, as shown in FIG. 3, if a bypass path is set up at monitored station C and the network configuration is changed, monitoring station 2 can use not only semi-fixed tables but also information obtained through periodic polling. The contents of the table also do not match the network configuration at the time of the failure due to the time lag between polling and failure.
従つて、従来方式によりループの再構成を行な
うと、監視局２は局内のテーブルを参照しながら
ループの再構成を行つているため、バイパス路を
設定している被監視局Ｃに対しても監視信号を送
出する。当然のことながら被監視局Ｃからは監視
信号は返送されない。したがつて監視局２は被監
視局Ｄ，Ｃ間あるいは被監視局Ｃに障害があると
みなし、被監視局Ｄにおいて折り返し路を設定す
る。よつて第３図２の如くループが再構成され
る。このように従来方式では被監視局Ｂが正常で
あるにもかかわらず被監視局Ｄで折り返し路が設
定されてしまうので、障害を含む区間のみをとり
除き、ループの有効区間を最大とするような折り
返し路の設定ができない場合がある。 Therefore, when the loop is reconfigured using the conventional method, the monitoring station 2 reconfigures the loop while referring to the table within the station. Sends a monitoring signal. Naturally, no monitoring signal is sent back from the monitored station C. Therefore, the monitoring station 2 considers that there is a fault between the monitored stations D and C or in the monitored station C, and sets a return route at the monitored station D. Therefore, the loop is reconfigured as shown in FIG. 3. In this way, in the conventional method, a return route is set at monitored station D even though monitored station B is normal. Therefore, only the section including the fault is removed to maximize the effective section of the loop. In some cases, it may not be possible to set a return route.
本発明は上述の欠点を除去し、あらかじめ被監
視局内の局アドレスと接続位置との対応を監視局
において知ることなく、障害発生時の網構成にそ
くした局折り返しによるループの再構成方式を提
供することを目的とし、監視局と複数の被監視局
が２本の伝送路でループ状に接続された二重化ル
ープ伝送網において、
すべての批監視局に対し有効であり、被監視局
に対し、一方の伝送路を他方の伝送路へ折り返す
と同時に自局アドレスを他方の伝送路により監視
局へ返送する動作を実行させる折り返し命令と、
特定の被監視局を指定するためのアドレス付命
令であつて、該アドレスで指定された被監視局に
対し、上記折り返し命令によつて設定された折り
返し路を解除すると同時に以後の折り返し命令を
受付不可の状態とする折り返し禁止命令と、
特定の被監視局を指定するためのアドレス付命
令であつて、該アドレスで指定された被監視局に
対し、一方の伝送路を他方の伝送路へ折り返す動
作を実行させる折り返し路設定命令とを、
そなえ、
伝送路に障害が発生したとき監視局より被監視
局に対して上記折り返し命令を発し、
当該折り返し命令を受領した被監視局より局ア
ドレスが返送された場合には当該局アドレスを監
視局において記憶するとともに、監視局より当該
局アドレスの被監視局に対して上記折り返し禁止
命令を発し、しかる後、監視局より被監視局に対
して上記折り返し命令を再び発する動作を繰り返
し行うことにより、上記折り返し命令を順次後位
の被監視局へ伝達せしめ、
一方、監視局より被監視局に対して上記折り返
し命令を発した後、いずれの局アドレスも返送さ
れない場合には、当該折り返し命令の直前に発行
された折り返し命令により返送された局アドレス
を有する被監視局に対して上記折り返し路設定命
令を発し、当該被監視局において折り返し路を設
定させることを特徴とするものである。 The present invention eliminates the above-mentioned drawbacks and provides a loop reconfiguration method by station loopback in accordance with the network configuration at the time of failure, without requiring the monitoring station to know in advance the correspondence between station addresses and connection positions within the monitored station. In a duplex loop transmission network in which a monitoring station and multiple monitored stations are connected in a loop through two transmission lines, it is effective for all monitoring stations, and for monitored stations. A loopback command that causes one transmission line to loop back to the other transmission line and at the same time returns its own station address to the monitoring station via the other transmission line, and an address-attached command that specifies a specific monitored station. a return prohibition command that cancels the return route set by the return command for the monitored station specified by the address, and at the same time makes it impossible to accept subsequent return commands; and a specific monitored station. a command with an address for specifying the address, and a return route setting command that causes the monitored station designated by the address to perform an operation of returning one transmission route to the other transmission route; When a failure occurs in the monitoring station, the monitoring station issues the above-mentioned return command to the monitored station, and if the station address is returned from the monitored station that received the return command, the station address is stored in the monitoring station. , the monitoring station issues the above-mentioned call-back prohibition command to the monitored station at the station address, and then the monitoring station issues the above-mentioned call-back command to the monitored station repeatedly, thereby issuing the above-mentioned call-back command. On the other hand, if no station address is returned after the monitoring station issues the above return command to the monitored station, the address of the station issued immediately before the return command is transmitted to the subsequent monitored stations in sequence. The present invention is characterized in that the return route setting command is issued to the monitored station having the station address returned by the return command, and the return route is set in the monitored station.
以下に図を用いて本発明を詳細に説明する。第
４図は、本発明にかかるループ再構成方式で使用
するフレームフオーマツトの一例である。 The present invention will be explained in detail below using the figures. FIG. 4 is an example of a frame format used in the loop reconfiguration method according to the present invention.
本図において３はフレーム同期信号、４は宛先
局アドレス、５は発信局アドレス、６は監視用サ
ブフレーム、７は局間伝送用フレーム、８はコヤ
ンド部、９は局アドレス部、１０はレスポンス部
である。 In this figure, 3 is a frame synchronization signal, 4 is a destination station address, 5 is a source station address, 6 is a monitoring subframe, 7 is a frame for inter-station transmission, 8 is a coyan part, 9 is a station address part, and 10 is a response Department.
本図に示すように本発明にかかるループ再構成
方式においてはフレームフオーマツト中に新たに
監視用サブフレームを受けとつた被監視局が自局
アドレスを書込む領域を設けた。なおコマンド部
８には監視局２より被監視局に対し所定の動作を
行わさせる命令が書込まれ、レスポンス部１０に
は、被監視局の電源等の状態に関するデータが被
監視局において書込まれる。 As shown in the figure, in the loop reconfiguration method according to the present invention, an area is provided in the frame format in which a monitored station that newly receives a monitoring subframe writes its own station address. Note that the command section 8 is written with a command from the monitoring station 2 that causes the monitored station to perform a predetermined operation, and the response section 10 is written with data regarding the status of the power supply, etc. of the monitored station. It will be done.
本発明にかかるループ再構成方式では上述のフ
レームフオーマツトを使用すると同時に以下の特
徴的な命令を備える。 The loop reconfiguration method according to the present invention uses the above-mentioned frame format and also includes the following characteristic instructions.
折り返し命令：全被監視局に対し有効であ
り、一方の送路を他方の伝送路へ折り返すと同
時に自局アドレスを他方の伝送路により監視局
２へ返送させる。 Return command: Valid for all monitored stations, returns one transmission path to the other transmission path and at the same time causes the own station address to be returned to the monitoring station 2 via the other transmission path.
折り返し禁止命令：特定の被監視局を指定す
るためのアドレス付命令で、折り返し命令によ
つて設定された折り返し路を解除すると同時に
以後の折り返し命令を受可不可状態とする。 Return prohibition command: A command with an address for specifying a specific monitored station, which cancels the return path set by the return command and at the same time disables subsequent return commands.
折り返し路設定命令：特定の被監視局を指定
するアドレス付命令で、被監視局において一方
の伝送路を他方の伝送路へ折り返す折り返し路
を設定する。 Return path setting command: A command with an address that specifies a specific monitored station, and sets a return path that turns one transmission path back to the other transmission path in the monitored station.
以上の命令を用いた本発明にかかるループ再構
成方式を以下に説明する。 A loop reconfiguration method according to the present invention using the above instructions will be described below.
第５図は、本発明にかかるループ再構成方式の
説明図である。本図において第３図と同一番号は
同一部位を示す。なお、１〜５の順でループは再
構成される。 FIG. 5 is an explanatory diagram of the loop reconfiguration method according to the present invention. In this figure, the same numbers as in FIG. 3 indicate the same parts. Note that the loops are reconfigured in the order of 1 to 5.
第３図において示した障害が発生すると、監視
局２は、まず折り返し命令を現用系の伝送路１へ
送出する。折り返し命令は前述したように全被監
視局に対し有効であるから、伝送路１方向に監視
局にもつとも近い被監視局Ａにおいて実行され
る。被監視局Ａは折り返し命令を実行し伝送路１
を伝送路１′へ折り返し、自局のアドレスを監視
用サブフレーム６中の局アドレス部９に書込み、
伝送路１′により監視局２へ返送する。監視局２
は返送された局アドレスを記憶し、その局アドレ
スを用いて被監視局Ａに対し折り返し禁止命令を
発し、折り返し路を解除し、以後の折り返し命令
を受付不可状態とした後、再び折り返し命令を発
する。第６図１においては、被監視局Ａ，Ｂ間で
障害があるため局アドレスは返送されない。従つ
て監視局２は被監視局Ａ，Ｂ間で障害があるとみ
なし、直前の折り返し命令で得た局アドレスの被
監視局Ａに対し折り返し路設定命令を発し、被監
視局Ａにおいて第５図２の如く第一の折り返し路
が設定される。 When the failure shown in FIG. 3 occurs, the monitoring station 2 first sends a return command to the active transmission line 1. Since the return command is valid for all monitored stations as described above, it is executed at the monitored station A that is closest to the monitoring station in one direction of the transmission path. Monitored station A executes the return command and transfers transmission path 1.
is returned to the transmission path 1', and the address of the own station is written in the station address section 9 of the monitoring subframe 6.
It is sent back to the monitoring station 2 via the transmission path 1'. Monitoring station 2
memorizes the returned station address, uses that station address to issue a return prohibition command to monitored station A, cancels the return route, makes future return commands unacceptable, and then issues a return command again. emanate. In FIG. 6, there is a failure between monitored stations A and B, so no station address is returned. Therefore, monitoring station 2 considers that there is a fault between monitored stations A and B, issues a loopback route setting command to monitored station A whose station address was obtained from the previous loopback command, and then A first return route is set as shown in FIG.
さらに監視局２は第２の折り返し路を設定する
ため折り返し命令を送出する。折り返し命令は全
被監視局に対し有効なアドレス指定をしない命
令、すなわち最初に受け取つた局において実行さ
れるので、被監視局Ｄにおいて実行された後は、
バイパス路を設定している被監視局Ｃは無視され
被監視局Ｂにおいて実行される。このようにして
被監視局Ｂにおいて第５図５の如く第２の折り返
し路が設定されループの再構成が完了する。 Furthermore, the monitoring station 2 sends a return command to set up a second return route. The return command is a command that does not specify valid addresses for all monitored stations; in other words, it is executed at the first station that receives it, so after it is executed at monitored station D,
The monitored station C that has set the bypass path is ignored and the monitored station B executes the process. In this way, the second return route is set in the monitored station B as shown in FIG. 5, and the loop reconfiguration is completed.
以上のようにして被監視局Ａ，Ｄ，Ｂを含み障
害区間のみを除去したループが再構成される。 As described above, a loop including monitored stations A, D, and B and only the faulty section removed is reconfigured.
以上説明したように本発明によれば、あらかじ
め局アドレスと被監視局の接続位置との対応を監
視局２において知ることなく、障害発生時の網構
成にそくした障害区間のみをとり除き有効区間を
最大とするような局折り返しによるループの再構
成が可能であるので、障害発生時におけるシステ
ムの稼動率を向上させることができる。 As explained above, according to the present invention, without the monitoring station 2 knowing in advance the correspondence between the station address and the connection position of the monitored station, only the faulty section in accordance with the network configuration at the time of the fault occurrence is removed, and the valid section is removed. Since it is possible to reconfigure the loop by station loopback in such a way as to maximize the number of points, it is possible to improve the operating rate of the system when a failure occurs.
また、折り返し命令を実行するたびに局アドレ
スを返送させているのでループ再構成完了時には
監視局２において新しい網構成を知ることができ
る。 Furthermore, since the station address is returned every time the return command is executed, the new network configuration can be known at the monitoring station 2 when the loop reconfiguration is completed.
第１図は二重化ループ伝送網の概念図、第２図
は従来のループ再構成方式の説明図、第３図１は
二重化ループ伝送網における障害例、２は従来の
ループ再構成方式により再構成されたループ伝送
網、第４図は本発明にかかるフレームフオーマツ
ト、第５図は本発明にかかるループ再構成方式の
説明図である。
１……現用系伝送路、１′……予備系伝送路、
２……監視局、３……フレーム同期信号、４……
宛先局アドレス、５……発信局アドレス、６……
監視用サブフレーム、７……局間伝送用フレー
ム、８……コマンド部、９……局アドレス部、１
０……レスポンス部。
Figure 1 is a conceptual diagram of a duplexed loop transmission network, Figure 2 is an explanatory diagram of a conventional loop reconfiguration method, and Figure 3 is an example of a failure in a duplexed loop transmission network, and 2 is reconfiguration using a conventional loop reconfiguration method. FIG. 4 shows a frame format according to the present invention, and FIG. 5 is an explanatory diagram of a loop reconfiguration method according to the present invention. 1...working transmission line, 1'...protection transmission line,
2...Monitoring station, 3...Frame synchronization signal, 4...
Destination station address, 5... Source station address, 6...
Monitoring subframe, 7... Frame for inter-station transmission, 8... Command section, 9... Station address section, 1
0...Response part.
Claims (1)
ープ状に接続された二重化ループ伝送網におい
て、 すべての被監視局に対し有効であり、被監視局
に対し、一方の伝送路を他方の伝送路へ折り返す
と同時に自局アドレスを他方の伝送路により監視
局へ返送する動作を実行させる折り返し命令と、 特定の被監視局を指定するためのアドレス付命
令であつて、該アドレスで指定された被監視局に
対し、上記折り返し命令によつて設定された折り
返し路を解除すると同時に以後の折り返し命令を
受付不可の状態とする折り返し禁止命令と、 特定の被監視局を指定するためのアドレス付命
令であつて、該アドレスで指定された被監視局に
対し、一方の伝送路を他方の伝送路へ折り返す動
作を実行させる折り返し路設定命令とを、 そなえ、 伝送路に障害が発生したとき監視局より被監視
局に対して上記折り返し命令を発し、 当該折り返し命令を受領した被監視局より局ア
ドレスが返送された場合には当該局アドレスを監
視局において記憶するとともに、監視局より当該
局アドレスの被監視局に対して上記折り返し禁止
命令を発し、しかる後、監視局より被監視局に対
して上記折り返し命令を再び発する動作を繰り返
し行うことにより、上記折り返し命令を順次後位
の被監視局へ伝達せしめ、 一方、監視局より被監視局に対して上記折り返
し命令を発した後、いずれの局アドレスも返送さ
れない場合には、当該折り返し命令の直前に発行
された折り返し命令により返送された局アドレス
を有する被監視局に対して上記折り返し路設定命
令を発し、当該被監視局において折り返し路を設
定させることを特徴とする二重化ループ伝送網に
おける障害時ループ再構成方式。[Claims] 1. In a duplex loop transmission network in which a monitoring station and a plurality of monitored stations are connected in a loop through two transmission lines, the system is effective for all monitored stations and is effective for all monitored stations. , a loopback command that loops back one transmission line to the other transmission line and at the same time sends its own station address back to the monitoring station via the other transmission line, and a command with an address that specifies a specific monitored station. a return prohibition command that cancels the return path set by the return command for the monitored station specified by the address and at the same time makes it impossible to accept subsequent return commands; and a specific monitored station. A command with an address for specifying a station, and a return route setting command for causing the monitored station designated by the address to perform an operation of returning one transmission route to the other transmission route, are provided and transmitted. When a failure occurs on the road, the monitoring station issues the above-mentioned return command to the monitored station, and if the station address is returned from the monitored station that received the return command, the station address is stored in the monitoring station. At the same time, the monitoring station issues the above-mentioned call-back prohibition command to the monitored station at the station address, and then the monitoring station issues the above-mentioned call-back command to the monitored station again.By repeating this operation, the above-mentioned return command is issued. On the other hand, if no station address is returned after the monitoring station issues the above callback command to the monitored station, the Loop reconfiguration in the event of a failure in a duplex loop transmission network, characterized in that the above-mentioned return route setting command is issued to a monitored station having a station address returned by a return command, and the monitored station sets a return route. method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17438480A JPS5797754A (en) | 1980-12-10 | 1980-12-10 | Loop reconstituting system for fault of dual loop transmission network |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17438480A JPS5797754A (en) | 1980-12-10 | 1980-12-10 | Loop reconstituting system for fault of dual loop transmission network |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5797754A JPS5797754A (en) | 1982-06-17 |
| JPH0159780B2 true JPH0159780B2 (en) | 1989-12-19 |
Family
ID=15977667
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17438480A Granted JPS5797754A (en) | 1980-12-10 | 1980-12-10 | Loop reconstituting system for fault of dual loop transmission network |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5797754A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5940739A (en) * | 1982-08-30 | 1984-03-06 | Fujitsu Ltd | Loopback control system |
| JPS59209927A (en) * | 1983-05-06 | 1984-11-28 | デンプスタ−・システムズ・インコ−ポレイテツド | Hoist mechanism for truck or trailer type automobile |
| JPS6037851A (en) * | 1983-08-09 | 1985-02-27 | Mitsubishi Electric Corp | Information transmitting device for car |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55105457A (en) * | 1979-02-07 | 1980-08-13 | Toshiba Corp | Circuit formation accelerating method for data highway |
| JPS55147056A (en) * | 1979-05-02 | 1980-11-15 | Toshiba Corp | Line connecting system in channel multiplex |
-
1980
- 1980-12-10 JP JP17438480A patent/JPS5797754A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55105457A (en) * | 1979-02-07 | 1980-08-13 | Toshiba Corp | Circuit formation accelerating method for data highway |
| JPS55147056A (en) * | 1979-05-02 | 1980-11-15 | Toshiba Corp | Line connecting system in channel multiplex |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5797754A (en) | 1982-06-17 |
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