JPH05894B2 - - Google Patents
Info
- Publication number
- JPH05894B2 JPH05894B2 JP57209517A JP20951782A JPH05894B2 JP H05894 B2 JPH05894 B2 JP H05894B2 JP 57209517 A JP57209517 A JP 57209517A JP 20951782 A JP20951782 A JP 20951782A JP H05894 B2 JPH05894 B2 JP H05894B2
- Authority
- JP
- Japan
- Prior art keywords
- line
- signal
- transmitted
- sensor
- information
- 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 - Lifetime
Links
- 230000008054 signal transmission Effects 0.000 claims description 28
- 230000005540 biological transmission Effects 0.000 claims description 23
- 238000012544 monitoring process Methods 0.000 claims description 19
- 238000000034 method Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 8
- 239000000779 smoke Substances 0.000 description 7
- 238000001514 detection method Methods 0.000 description 5
- 230000002265 prevention Effects 0.000 description 3
- 230000005856 abnormality Effects 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
- G08B25/01—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium
- G08B25/08—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium using communication transmission lines
- G08B25/085—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium using communication transmission lines using central distribution transmission lines
Landscapes
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Time-Division Multiplex Systems (AREA)
Description
【発明の詳細な説明】
本発明は自火報システムや防排煙システム、あ
るいは負荷の監視制御システムなどに用いられる
情報伝送方式に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information transmission system used in fire alarm systems, smoke prevention systems, load monitoring and control systems, and the like.
第１図は従来の自動火災報知装置における情報
伝送方式を示すブロツク図である。同図におい
て、複数の感知器S1，S2…のうちの何れかが動作
するとリレーＸが動作し、その出力接点によつて
ベルや表示器等を動作させている。しかしてある
感知器S1が動作した時に発信器T1′から固有周波
数f1を有する信号を発生し、この信号をコンデン
サ結合にて伝送ラインに搬送、重畳すると共に、
受信機側では同じくコンデンサ結合でその周波数
成分を取出し、周波数判別回路１によつて前記固
有周波数f1の信号を判別し、アドレス表示回路２
にて感知器S1のアドレス表示を行なうようにして
いるものである。しかしながら、かかる固有周波
数を用いた情報伝送方式においては、固有周波数
の変更が困難であり、また多数の固有周波数につ
いてそれぞれ発信器やフイルタを用意する必要が
あつて生産性が悪いという問題があつた。そこで
従来、第２図に示すように、各感知器S1，S2…毎
に個別にアドレス設定されたパルスコード発信回
路T1，T2…を夫々接続し、各感知器S1，S2…の
動作時にパルスコード発信回路T1，T2…から発
生する各別のパルスコード信号を電圧検知回路３
により直流電圧の変化に置き換えてコード処理回
路４よつて上記パルスコードを検出判別し、アド
レス表示回路５によつて動作中の感知器S1，S2…
のアドレス表示を行なうようにしたポイントアド
レス方式が提案されている。しかしながらかかる
ポイントアドレス方式にあつては、感知器から受
信機に伝送される電圧レベルや電流レベルの変化
によつて例えば予備警報と本警報とを区別した
り、煙感知濃度を伝送したりするようなことはで
きないという問題があり、レベル変化による情報
とパルスコードによる情報とを併用することがで
きないという問題があつた。またかかる第１図お
よび第２図の従来例にあつては受信機本体と複数
個の感知器とを一対の信号伝送線を介して接続し
ているので、感知器の接続個数が増加すると、信
号伝送線の線間インピーダンスがそれだけ低下す
ることになり、また信号伝送線があまり長くなる
と、伝送信号の減衰が著しく増加するので正確な
信号伝送を行なうことができなくなるという問題
があつた。 FIG. 1 is a block diagram showing an information transmission system in a conventional automatic fire alarm system. In the figure, when any one of the plurality of sensors S 1 , S 2 . . . operates, a relay X operates, and its output contact operates a bell, an indicator, etc. However, when a certain sensor S 1 operates, a signal having a natural frequency f 1 is generated from the oscillator T 1 ′, and this signal is conveyed and superimposed on the transmission line by capacitor coupling, and
On the receiver side, the frequency component is similarly extracted by capacitor coupling, the frequency discrimination circuit 1 discriminates the signal of the natural frequency f 1 , and the address display circuit 2
The address of sensor S1 is displayed at . However, in the information transmission system using such natural frequencies, it is difficult to change the natural frequencies, and it is necessary to prepare transmitters and filters for each of the many natural frequencies, resulting in poor productivity. . Conventionally, as shown in FIG . 2 , pulse code transmitting circuits T 1 , T 2 . 2 The voltage detection circuit 3 detects the different pulse code signals generated from the pulse code transmission circuits T 1 , T 2 ... during the operation of ...
The code processing circuit 4 detects and discriminates the pulse code by replacing it with a change in the DC voltage, and the address display circuit 5 detects the operating sensors S 1 , S 2 . . .
A point address system has been proposed in which addresses are displayed. However, in the case of such a point address method, changes in the voltage level or current level transmitted from the sensor to the receiver can be used to distinguish, for example, between a preliminary alarm and a main alarm, or to transmit the detected smoke concentration. However, there was a problem in that information based on level changes and information based on pulse codes could not be used together. In addition, in the conventional examples shown in FIGS. 1 and 2, the receiver main body and the plurality of sensors are connected via a pair of signal transmission lines, so when the number of connected sensors increases, This causes a problem in that the line-to-line impedance of the signal transmission line decreases accordingly, and if the signal transmission line becomes too long, the attenuation of the transmitted signal increases significantly, making it impossible to perform accurate signal transmission.
本発明は従来例のこのような問題点を解決する
ために為されたものであり、信号伝送線による信
号伝送距離や信号伝送線への端末器の接続個数な
どを自由に設定することができ、しかも端末器か
らレベル信号とこのレベル信号に重畳する信号と
を同時に伝送できるようにして、レベル変化によ
る情報と重畳信号による情報とを同時に伝送でき
るようにした情報伝送方式を提供することを目的
とするものである。 The present invention was made to solve these problems of the conventional example, and allows the signal transmission distance of the signal transmission line and the number of terminal devices connected to the signal transmission line to be freely set. Moreover, it is an object of the present invention to provide an information transmission method that enables simultaneous transmission of a level signal and a signal superimposed on the level signal from a terminal device, thereby simultaneously transmitting information based on level changes and information based on the superimposed signal. That is.
以下本発明の構成を図示実施例について説明す
る。第３図は本発明の一実施例に係る情報伝送方
式を用いた防災監視システムを示すブロツク図で
ある。同図において６は中央監視制御装置であ
り、幹線７を介して複数個の回線中継器８が接続
されている。各回線中継器８には幹線７から分岐
する回線９がそれぞれ接続されており、各回線９
には監視制御用端末器１０や、一般感知器１１な
どが接続されている。監視制御用端末器１０はパ
ルスコード信号による伝送信号によつて被監視機
器１２の接点信号状態を中央監視制御装置６に返
送する機能と、中央監視制御装置６から伝送され
てくるパルスコード信号による伝送信号に含まれ
る制御情報に応じて無電圧接点出力を生じて、被
制御機器１３の制御を行なう機能がある。また一
般感知器１１は火災感知動作時や煙感知動作時な
どに回線９を適当な抵抗を介して短絡するなどし
て電流レベル、あるいは電圧レベルのようなレベ
ル信号を回線中継器８に伝送するものである。第
４図は回線中継器８に入力される回線９上の信号
の一例を示しており、一般感知器１１からのレベ
ル信号に、監視制御用端末器１０からのパルスコ
ード信号による伝送信号が重畳しているものであ
る。かかるレベル信号によつて表わされる情報お
よび伝送信号によつて表わされる情報は、それぞ
れ回線中継器８においてパルスコード信号よりな
る伝送信号に変換されて中央監視制御装置６に幹
線７を介して伝送されるようになつている。また
中央監視制御装置６は各回線中継器８に対して個
別に割り当てたアドレス信号を含むパルスコード
信号よりなる伝送信号を幹線７を介して送出して
おり、回線中継器８はアドレス信号が自局のアド
レスと一致したときには上記伝送信号を回線９に
伝送するようにしている。この際、幹線７と回線
９との電圧レベルは回線中継器８によつて分離さ
れるから、回線９の伝送距離の上限と、幹線７の
伝送距離の上限とは別個に定めることができるも
のである。しかして回線中継器８と中央監視制御
装置６とを結ぶ幹線７上の信号の送受はレベル信
号を用いないでパルスコード信号よりなる伝送信
号のみを用いて行なつている。ここで回線中継器
８と中央監視制御装置６とを結ぶ幹線７には電源
線を並設して電源供給を行なつてもかまわない
が、信号伝送用の幹線７を電源供給線として兼用
するようにしてもかまわない。また回線中継器８
から分岐せる回線９は信号伝送線としての機能
と、電源供給線としての機能とを兼用しているも
のである。中央監視制御装置６は各回線中継器８
および回線中継器８に属する監視制御用端末器１
０を順次時分割的にポーリングして、被監視機器
１２の状態や、回線中継器８の動作および幹線７
や回線９の状態を常時監視するようにしており、
異常があれば中央監視制御装置６において表示す
るようにしているものである。 The configuration of the present invention will be described below with reference to illustrated embodiments. FIG. 3 is a block diagram showing a disaster prevention monitoring system using an information transmission system according to an embodiment of the present invention. In the figure, reference numeral 6 denotes a central monitoring and control device, to which a plurality of line repeaters 8 are connected via a main line 7. A line 9 branching from the main line 7 is connected to each line repeater 8.
A monitoring control terminal 10, a general sensor 11, etc. are connected to the terminal. The supervisory control terminal 10 has a function of transmitting the contact signal state of the monitored device 12 to the central supervisory controller 6 using a transmission signal based on a pulse code signal, and a function of transmitting a contact signal state of the monitored device 12 to the central supervisory controller 6 using a pulse code signal transmitted from the central supervisory controller 6. It has a function of controlling the controlled device 13 by generating a non-voltage contact output according to the control information included in the transmission signal. In addition, the general detector 11 transmits a level signal such as a current level or voltage level to the line repeater 8 by short-circuiting the line 9 through an appropriate resistor during fire detection operation, smoke detection operation, etc. It is something. FIG. 4 shows an example of a signal on the line 9 that is input to the line repeater 8, in which a level signal from the general sensor 11 is superimposed with a transmission signal based on a pulse code signal from the supervisory control terminal 10. This is what we are doing. The information represented by the level signal and the information represented by the transmission signal are each converted into a transmission signal consisting of a pulse code signal at the line repeater 8 and transmitted to the central supervisory control device 6 via the main line 7. It is becoming more and more common. In addition, the central supervisory control device 6 sends a transmission signal consisting of a pulse code signal including an individually assigned address signal to each line repeater 8 via the main line 7. When the address matches the address of the station, the transmission signal is transmitted to the line 9. At this time, since the voltage levels of the trunk line 7 and line 9 are separated by the line repeater 8, the upper limit of the transmission distance of line 9 and the upper limit of the transmission distance of trunk line 7 can be determined separately. It is. Thus, the transmission and reception of signals on the main line 7 connecting the line repeater 8 and the central supervisory control unit 6 is carried out using only a transmission signal consisting of a pulse code signal without using a level signal. Here, a power line may be installed in parallel to the main line 7 connecting the line repeater 8 and the central monitoring and control device 6 to supply power, but the main line 7 for signal transmission may also be used as a power supply line. It doesn't matter if you do it like this. Also, line repeater 8
The line 9 branched from the line 9 serves both as a signal transmission line and as a power supply line. The central monitoring and control device 6 connects each line repeater 8
and a supervisory control terminal 1 belonging to the line repeater 8
0 in a time-sharing manner to check the status of the monitored device 12, the operation of the line repeater 8, and the main line 7.
and the status of line 9 are constantly monitored.
If there is an abnormality, it is displayed on the central monitoring and control device 6.
次に第５図は本発明の他の実施例を示してお
り、同図において１４はインテリジエンスセンサ
であり、感知器の検知レベルを回線９に伝送する
と共に、回線９を介して伝送されてくるチエツク
情報により感知器の動作チエツクを行なうもので
ある。また１５は感知器の監視用端末器であり、
感知器の電圧レベル信号を感知器発報として回線
９に伝送するものである。さらに１６は一般の煙
感知器、１７は一般の熱感知器であり、それぞれ
煙および熱の感知時には回線９に感知信号をレベ
ル信号として伝送するものである。また１８は回
線９の終端に接続される終端器である。次に１９
はインテリジエンス中継器であり、小規模受信機
に相当する機能を有し、かつホストコンピユータ
に相当する中央監視制御装置６と幹線７を介して
情報交換できるようになつている。このインテリ
ジエンス中継器１９に接続された他の回線９に
は、火災報知ベルＢや防排煙システムERを起動
制御するための監視制御用端末器１０が接続され
ており、これらの各監視制御用端末器１０にはベ
ル用電源線２０およびロツク用電源線２１がそれ
ぞれ接続されている。 Next, FIG. 5 shows another embodiment of the present invention, in which reference numeral 14 is an intelligence sensor, which transmits the detection level of the sensor to the line 9, and also transmits the detection level of the sensor via the line 9. The operation of the sensor is checked based on the check information received. 15 is a terminal for monitoring the sensor;
The voltage level signal of the sensor is transmitted to the line 9 as a sensor alarm. Furthermore, 16 is a general smoke detector, and 17 is a general heat sensor, which respectively transmit a sensing signal to the line 9 as a level signal when detecting smoke or heat. Further, 18 is a terminator connected to the end of the line 9. Next 19
is an intelligence repeater, which has functions equivalent to a small-scale receiver, and is capable of exchanging information via a trunk line 7 with a central monitoring and control device 6, which corresponds to a host computer. The other line 9 connected to this intelligence repeater 19 is connected to a supervisory control terminal 10 for starting and controlling the fire alarm bell B and the smoke prevention and exhaust system ER, and these supervisory and control terminals 10 are connected to each other. A bell power line 20 and a lock power line 21 are connected to the terminal 10, respectively.
本発明は以上のように構成されており、中央監
視制御装置に第１の信号伝送線を介して複数個の
回線中継器を接続し、各回線中継器に第２の信号
伝送線を介して感知器と、端末器とを接続し、感
知器の感知動作によつて第２の信号伝送線の電圧
や電流のレベルを変化させたレベル信号を感知器
より第２の信号伝送線を介して伝送し、端末器の
制御情報または監視情報をレベル信号に重畳させ
た重畳信号により伝送するようにしたものである
から、第２の信号伝送線上を伝送される電圧レベ
ルや電流レベルのレベル信号の変化によつて感知
器の感知動作を通常の感知器回線と同様に回線中
継器に伝えることができるものであつて、またレ
ベル信号とパルスコード信号のような伝送信号よ
りなる重畳信号とが第２の信号伝送線上に混在で
きるので、一般の煙感知器や熱感知器のような接
点が閉じるだけの標準感知器と、伝送信号に応じ
て負荷の制御や監視を行なう端末器とを第２の信
号伝送線上に混在させることができ、通常の感知
器の火災発報の監視以外に多様な監視制御が可能
となるとともに回線数の節約が可能となるととも
に回線数の節約が可能になるという利点があり、
また本発明にあつては、第１の信号伝送線を介し
て中央監視制御装置から各回線中継器にアドレス
信号と、端末器に伝送する制御情報を含む制御信
号とを伝送し、回線中継器から中央監視制御装置
に端末器からの監視情報を含む監視信号を返送す
るようにしたものであるから、第２の信号伝送線
を介して伝送されるレベル信号および重畳信号を
回線中継器において制御信号および監視信号とし
て第１の信号伝送線上に伝送させることができ、
したがつて第１および第２の信号伝送線の伝送距
離の上限を別個に設定することができ、また第２
の信号伝送線に多数の端末器を接続しても第１の
信号伝送線の線間インピーダンスは低下しないの
で端末器の接続個数も自由に設定することができ
るという利点があり、さらにまた中央監視制御装
置から各回線中継器に対してはアドレス信号と制
御信号とが伝送されており、回線中継器から中央
監視制御装置に対しては監視信号が返送されてい
るので、中央監視制御装置からのポーリングによ
り回線中継器の異常の常時監視を行なうこともで
きるものである。 The present invention is configured as described above, in which a plurality of line repeaters are connected to the central monitoring and control device via a first signal transmission line, and a plurality of line repeaters are connected to each line repeater via a second signal transmission line. A sensor and a terminal are connected, and a level signal that changes the voltage or current level of a second signal transmission line by the sensing operation of the sensor is transmitted from the sensor through the second signal transmission line. Since the control information or monitoring information of the terminal device is transmitted by a superimposed signal in which the control information or monitoring information of the terminal device is superimposed on the level signal, the level signal of the voltage level or current level transmitted on the second signal transmission line is The sensing operation of the sensor can be transmitted to the line repeater by the change in the same way as a normal sensor line, and a superimposed signal consisting of a level signal and a transmission signal such as a pulse code signal is Since the two signal transmission lines can coexist, standard sensors such as general smoke detectors and heat detectors that only close the contacts, and terminal devices that control and monitor the load according to the transmission signal can be used as the second signal transmission line. can be mixed on signal transmission lines, making it possible to perform a variety of monitoring and control functions in addition to monitoring fire alarms from ordinary detectors, and also to save on the number of lines. There are advantages,
Further, in the present invention, an address signal and a control signal including control information to be transmitted to a terminal device are transmitted from the central supervisory control device to each line repeater via the first signal transmission line, and the line repeater Since the monitor signal containing the monitor information from the terminal device is sent back to the central supervisory control device from the terminal device, the level signal and superimposed signal transmitted via the second signal transmission line are controlled at the line repeater. can be transmitted on the first signal transmission line as a signal and a monitoring signal;
Therefore, the upper limit of the transmission distance of the first and second signal transmission lines can be set separately, and
Even if a large number of terminal devices are connected to the first signal transmission line, the line-to-line impedance of the first signal transmission line does not decrease, so there is an advantage that the number of terminal devices connected can be freely set. Address signals and control signals are transmitted from the control device to each line repeater, and supervisory signals are sent back from the line repeater to the central supervisory control unit. It is also possible to constantly monitor abnormalities in the line repeater by polling.
第１図は従来例のブロツク図、第２図は他の従
来例のブロツク図、第３図は本発明の一実施例の
ブロツク図、第４図は同上の動作波形図、第５図
は本発明の他の実施例のブロツク図である。
６は中央監視制御装置、７は幹線、８は回線中
継器、９は回線、１０は監視制御用端末器、１１
は一般感知器である。
Fig. 1 is a block diagram of a conventional example, Fig. 2 is a block diagram of another conventional example, Fig. 3 is a block diagram of an embodiment of the present invention, Fig. 4 is an operation waveform diagram of the same as above, and Fig. 5 is a block diagram of another conventional example. FIG. 3 is a block diagram of another embodiment of the present invention. 6 is a central supervisory control device, 7 is a trunk line, 8 is a line repeater, 9 is a line, 10 is a supervisory control terminal, 11
is a general sensor.
Claims (1)
て複数個の回線中継器を接続し、各回線中継器に
第２の信号伝送線を介して感知器と、端末器とを
接続し、感知器の感知動作によつて第２の信号伝
送線の電圧や電流のレベルを変化させたレベル信
号を感知器より第２の信号伝送線を介して伝送
し、端末器の制御情報または監視情報をレベル信
号に重畳させた重畳信号により伝送すると共に、
第１の信号伝送線を介して中央監視制御装置から
各回線中継器にアドレス信号と、端末器に伝送す
る制御情報を含む制御信号とを伝送し、回線中継
器から中央監視制御装置に端末器からの監視情報
を含む監視信号を返送することを特徴とする情報
伝送方式。1 Connecting a plurality of line repeaters to the central monitoring and control device via a first signal transmission line, connecting a sensor and a terminal device to each line repeater via a second signal transmission line, A level signal in which the voltage or current level of the second signal transmission line is changed by the sensing operation of the sensor is transmitted from the sensor via the second signal transmission line, and control information or monitoring information of the terminal device is transmitted. is transmitted by a superimposed signal superimposed on a level signal, and
An address signal and a control signal including control information to be transmitted to the terminal device are transmitted from the central supervisory control device to each line repeater via the first signal transmission line, and from the line repeater to the central supervisory control device the terminal device. An information transmission method characterized by sending back a monitoring signal containing monitoring information from.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57209517A JPS5999836A (en) | 1982-11-30 | 1982-11-30 | Information transmission system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57209517A JPS5999836A (en) | 1982-11-30 | 1982-11-30 | Information transmission system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5999836A JPS5999836A (en) | 1984-06-08 |
| JPH05894B2 true JPH05894B2 (en) | 1993-01-07 |
Family
ID=16574097
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57209517A Granted JPS5999836A (en) | 1982-11-30 | 1982-11-30 | Information transmission system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5999836A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS504910A (en) * | 1973-05-10 | 1975-01-20 |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5785777U (en) * | 1980-11-14 | 1982-05-27 |
-
1982
- 1982-11-30 JP JP57209517A patent/JPS5999836A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS504910A (en) * | 1973-05-10 | 1975-01-20 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5999836A (en) | 1984-06-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4847595A (en) | Alarm system | |
| JPS60117939A (en) | Information transmission system | |
| US4740787A (en) | Centralized monitoring method for security system | |
| EP0269747B1 (en) | Transmission circuit of facilities for preventing disasters | |
| JPH05894B2 (en) | ||
| JPH0341878B2 (en) | ||
| JPS61295738A (en) | Transmission controller | |
| JP2589208B2 (en) | Fire detector | |
| JP3541161B2 (en) | Wireless repeater | |
| JPH0218759B2 (en) | ||
| JP2019071131A (en) | Radio disaster prevention system and setting device for the same | |
| JPS5999595A (en) | Information transmission system | |
| JPH02214239A (en) | Signal transmission circuit in transmission line | |
| JP2517864Y2 (en) | Disaster prevention repeater | |
| KR100226317B1 (en) | Automated guided information transmitter-receiver | |
| JP3261266B2 (en) | Fire detector | |
| JPS6197244U (en) | ||
| KR970000823B1 (en) | Alarm apparatus in a home automation and the same control method | |
| JPS62173830A (en) | System for detecting disconnection of time division multiplex transmission system | |
| JP3372136B2 (en) | Communication error detection system in disaster prevention system using multiplex transmission | |
| JP2019067424A (en) | Setting device of radio disaster prevention system and relay node | |
| JPS60204144A (en) | Fault detecting system in bus type communication system | |
| JPH027119B2 (en) | ||
| JPS62171346A (en) | Terminating equipment for data transmission line | |
| JPH08249578A (en) | Terminal equipment of fire alarm facilities |