JP2761993B2 - Bus type network system and its repeater device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a repeater device and a bus-type network system including the repeater device.
In particular, the present invention relates to a transmission line failure detection method , a warning / display method when a failure occurs , and a failure recovery means in a repeater device or an optical repeater device for extending a transmission distance.

[0002]

2. Description of the Related Art In a bus type network, when data is transmitted between two stations located beyond the maximum transmission distance of a single cable, a repeater device or an amplifier for amplifying an electric signal to extend the transmission distance. An optical repeater device that converts the converted electric signal into an optical signal is used.

[0003] As shown in FIG .
That are located beyond the maximum transmission distance of
To connect the station 31 and the station 32
A bus network system using a repeater device is
The transceiver 22a and the transceiver are connected to the coaxial cable 21a.
Station 3 connected by sheaver cable 23a
1, the transceiver 22b and the coaxial cable 21c.
Stations connected by transceiver cable 23b
Section 32, a pair of repeater apparatuses 1a and 1b, and a coaxial cable.
Cable 21b, the transceiver 22a and the repeater device.
Transceiver 24a for connecting to
Cable 25a, coaxial cable with repeater device 1a
Transceiver 21c for connecting the
Sheaver cable 25c, coaxial cable 21b and repeater
Transceiver 24d for connecting to the
Transceiver cable 25d, repeater device 1b and the
Transceiver 24b for connecting to transceiver 22b and
And a transceiver cable 25b.

In order to simplify the following description, a transceiver for connecting a coaxial cable to a repeater device or an optical repeater device and a transceiver cable are abbreviated as a "connection portion to a coaxial cable".

As shown in FIG. 4, the bus-type network system uses optical fibers 42a and 42b between the optical repeaters even when the optical repeaters 41a and 41b are used.
Otherwise, the configuration is the same as that of the repeater device.

In a bus type network system using such a repeater device or an optical repeater device, a connection portion between the repeater device and the coaxial cable on both sides of the repeater device or a connection portion between the optical repeater device and the coaxial cable / optical fiber. There is a problem that data transmission between the station 31 and the station 32 cannot be performed due to disconnection or disconnection of the connector at the connection portion.

As a solution to such a problem, in the technique described in Japanese Patent Application Laid-Open No. 1-125133, in a bus type network system using an optical repeater device, when one of the optical fibers is disconnected, the disconnection occurs. Is detected, the data transmission between the optical repeater devices is interrupted, and the coaxial cable connected by the optical repeater device is separated to prevent the system from going down.
That is, in the example shown in FIGS. 3 and 4, a plurality of stations 31 and 3 are connected to the coaxial cables 21a and 21c, respectively.
2 is connected, and when the system goes down, data transmission between the stations 31 and between the stations 32 becomes impossible. However, if the system going down is prevented as described above, the data between the optical repeater devices can be transmitted. Even if the transmission is interrupted, data transmission between the stations 31 and between the stations 32 can be continued.

[0008]

In the above-mentioned prior art, there is a problem that disconnection and disconnection of a connector at a connection portion with a coaxial cable to which a station is connected cannot be detected. Further, no consideration is given to the notification means when both of the two optical fibers are disconnected, and there is a possibility that the optical repeater device cannot recognize that the optical fiber has been disconnected.

Japanese Patent Application Laid-Open No. 63-59144 discloses a technique for detecting a disconnection of a line in a local area network by applying a DC voltage to a transmission line, detecting a change in the line voltage, and detecting a line abnormality. It has been disclosed. However, in this technique, a power supply for detection, wiring and a connector for connecting the power supply to the line are required, and the possibility of disconnection and disconnection of the connector increases again.

Japanese Patent Application Laid-Open No. 63-90230 discloses a technique for monitoring the state of a signal to be relayed and transmitting, and stopping a signal relay process when a signal abnormality is monitored. However, in this technology, even if a transmission line abnormality occurs, the transmission line abnormality is not detected until the transmitted (relayed) signal is received and the signal abnormality is detected, and the recovery process is delayed. Inevitable.

An object of the present invention is to interrupt data transmission.
Repeater or optical repeater with means to minimize
Peter apparatus and bus type network system including them
System.

[0012]

The present invention achieves the above object.
In order to achieve this, it has a connection part with the transmission line in two directions, and is reset by a reception circuit / collision detection circuit that inputs an electric signal from each connection part, and a signal input to the reception circuit / collision detection circuit a monitoring unit, there is no signal input when there is no signal input exceeds the time set in the monitoring unit
Outputs a signal indicating that the table that the signal input is not
A signal generating circuit for outputting a warning signal if no response signal notifying the reception of the to signal, means for warning or display that there is no response signal is activated by the warning signal, the receiving circuit, collision detection A data control circuit that relays a signal input from a circuit or a signal from a signal generation circuit and returns the response signal when a signal is input to a reception circuit, and a transmission circuit that outputs a signal from the data control circuit. We propose a repeater device for a bus-type network comprising
You.

The present invention also achieves the above object.
Because, a connecting portion of the coaxial cable, a receiving circuit, collision detection circuit for inputting an electric signal from the connecting unit, the light and converts the signal from the receiving optical fiber to an electric signal - electrical converter, receiving circuit-collision detection circuit and the light - a monitoring means which is reset by a signal input to the electric conversion circuit, there is no signal input when there is no signal input exceeds the time set in the superintendent <br/> viewing means Outputting a signal indicating that the signal
A signal generating circuit for outputting a warning signal if no response <br/> answer signal indicating that a signal has been received indicating that the input is no, warning that there is no response signal is activated by the warning signal or Display means, a transmission circuit for outputting a signal input to the optical-electrical conversion circuit or a signal from the signal generation circuit, and a signal or a signal generation circuit input to the reception circuit / collision detection circuit / optical-electrical conversion circuit It relays the signals from the light - the response if the signal to electrical conversion circuit is input
An optical repeater device of a bus network comprising a data control circuit for returning a response signal and an electro-optical conversion circuit for converting a signal from the data control circuit to an optical signal is proposed.

Further, the receiving circuit , the collision detecting circuit , the transmitting circuit , the optical-to-electrical converting circuit , the electrical-to-optical converting circuit, and the respective transmission paths are provided in a plurality of paths so that the paths can be switched. By doing so, a multiplex configuration is achieved.

[0015]

The repeater device and the optical repeater device of the present invention firstly input signals from a connection portion with a transmission line (coaxial cable) on the side of the opposing repeater device or optical repeater device or a connection portion with an optical fiber. A pair of repeater devices or optical repeater devices can monitor each other by monitoring and returning a response to the opposing repeater device or optical repeater device if there is a signal input. Further, when there is no signal input exceeds the monitoring time set in the monitoring means, the signal input
A signal indicating no power is transmitted to the other repeater device or optical repeater device and the common transmission line. signal
The repeater device that transmitted the signal indicating that there is no input, and
And the optical repeater device outputs a signal indicating that there is no signal input.
If a response signal notifying that the signal has been received cannot be received, the connection to the coaxial cable or disconnection of the optical fiber
It recognizes that the connector has been disconnected, displays a warning and sends a warning signal. The repeater device and the optical repeater device other than the repeater device and the optical repeater device and the station can recognize that the disconnection or the like has occurred upon receiving the warning signal, so that the connection portion of the repeater device and the optical repeater device with the coaxial cable or Disconnection of optical fiber and disconnection of connector can be found.

Second, a plurality of receiving circuits, collision detecting circuits, transmitting circuits, optical-to-electrical converting circuits, electrical-to-optical converting circuits, and a plurality of transmission lines are provided, and a connection portion with a coaxial cable is provided. Or, monitor the input signal from the connection to the optical fiber, and if there is no signal input for longer than the set monitoring time, recognize that the connection to the coaxial cable or disconnection of the optical fiber or disconnection of the connector has occurred and route Switch. Thereby,
It is possible to reduce the period during which data cannot be transmitted due to the connection of the repeater device and the optical repeater device to the coaxial cable or the disconnection of the optical fiber or the disconnection of the connector.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
I will tell. Figure 1 shows a circuit block diagram of a first embodiment of the repeater device of the present invention, FIG. 3 is a system block diagram of a network to which the repeater <br/> motor device is used, FIG. 5 disconnection in the network state (position)
FIG. 8 is a time chart showing a normal repeater operation of the network shown in FIG. 3, and FIG. 9 is a time chart showing a repeater operation of the network shown in FIG. 3 when the network is disconnected. is there. In the following description, one of the pair of repeater devices 1 in FIGS. 3 , 5 , 8 , and 9 is referred to as a repeater device 1a, and the other is referred to as a repeater device 1b.

The repeater device 1 converts signals output to the coaxial cables 21a, 21b, 21c, which are common transmission paths (buses), into transceivers 24a, 24b, 24c, 24d and
And transceiver cables 25a, 25b, 25c, 25
receiving circuit 7 for receiving via the receiving lines 10a and 10b
a, 7b and the signals output to the coaxial cables 21a, 21b, 21c collide with the transceivers 24a, 2b.
The collision detection circuit 8a receives collision signals output from the transmission cables 4b, 24c, and 24d via the collision lines 11a and 11b of the transceiver cables 25a, 25b, 25c, and 25d.
8b, receiving circuits 7a and 7b, and collision detecting circuits 8a and 8b
Relays the received signal or the signal from the signal generating circuit 4 to the coaxial cable side, and transmits the data signal to the receiving circuits 7a and 7b.
And a data control circuit 2a to return a response signal if there is signal signal input indicating that signal is not input and 2b,
Transmission circuits 6a, 6b for outputting input signals to data control circuits 2a, 2b to coaxial cables 21a, 21b, 21c
And a transmission line 9a, 9b. The timer 3 is a monitoring means which is reset when a signal is input to the data control circuits 2a, 2b so that the monitoring time can be changed.
a, 3b and no signal input to output when there is no signal input for more than the monitoring time set in the timers 3a, 3b.
And a signal generator 4 and a warning-display circuit 5 generates a warning signal to be output when there is no response signal to the signal indicating that the signal and the signal input is not representative and.

FIG. 3 shows an example of a bus type network system using the repeater device 1. The illustrated bus type network system includes a station 31 and a station 31 which are connected to coaxial cables 21a and 21c and are located beyond the maximum transmission distance of a segment (one coaxial cable) via transceivers 22a and 22b and transceiver cables 23a and 23b. 32, a pair of repeaters 1a and 1b and a coaxial cable 21b are connected to a transceiver 24.
a, 24b, 24c, 24d and transceiver cables 25a, 25b, 25c, 25d.

The operation of the repeater 1 during normal data transmission in the above system using the pair of repeaters 1a and 1b will be described below with reference to FIG.
The data transmitted from the station 31 includes the transceiver cable 23a, the transceiver 22a, and the coaxial cable 2a.
1a, the transceiver 24a, and the receiving line 10a in the transceiver cable 25a, the signal is input to the receiving circuit 7a of the repeater device 1a, and further input to the data control circuit 2a. The data control circuit 2a resets the timer 3a when a signal is input, and the input data signal 120 is output to the transceiver cable 25c, the transceiver 24c, and the coaxial cable 21b via the transmission circuit 6b and the transmission line 9b. It is sent to the other opposing repeater device 1b.

In the opposing repeater device 1, the receiving line 1 of the transceiver 24d and the transceiver cable 25d
0a to the receiving circuit 7a and the data control circuit 2a by the data signal 120 inputted from the receiving circuit.
It is reset and transmission circuit 6b timer 3a, as well as the output to the coaxial cable 21c via the transmission line 9b, to create a response signal 121 to the data reception, the transmission circuit 6a, coaxial cable via a transmission line 9a 21b, and sends a response signal 121 to the repeater apparatus 1a as the transmission source.
return it. At the time of normal data transmission, by repeating this response confirmation, the pair of repeaters 1 can monitor each other.

When the data transmission amount is small (the data transmission interval is large) and the time 125 set in the timer 3a of the repeater 1b has expired, the signal generation circuit 4 is activated and the data control circuits 2a, 2b and transmission circuit 6a, via 6b, signal 1 indicating that the signal input is not in the repeater unit 1a and stearyl <br/> Shon 31
22 is output. Signal 12 indicating no signal input
Repeater 1a and the station 3 has received 2
1 and 32 return the response signal 121, and the repeater device 1b
It can be confirmed that the abnormality is not in the transmission path and receiving the response signal 121.

In a bus network, a coaxial cable
When any signal is transmitted to the (bus), the signal propagates to the entire system, so that any one of the stations 31 and 32 transmits data, or when a plurality of stations transmit data simultaneously and a collision occurs. Before
Serial repeater 1a, 1b each timer 3a, 3b
Will be reset.

Next, the operation of the network system using the pair of repeaters 1a and 1b when the connection between the repeater and the coaxial cable (the position indicated by the mark x in FIG. 5) is broken will be described below.

The receiving line 10a and the collision line 11a in the transceiver cable 25a connecting the coaxial cable 21a and the repeater device 1a via the transceiver 24a are disconnected or the connector of the transceiver cable 25a is disconnected (hereinafter, referred to as a connector).
In order to simplify the explanation, disconnection of the receiving lines 10a and 10b and the collision lines 11a and 11b in the transceiver cable 25a or disconnection of the connector of the transceiver cable 25a is performed.
When a disconnection occurs, there is no signal input to the receiving circuit 7a and the collision detecting circuit 8a. Therefore, the timer 3a is not reset even if it exceeds the set monitoring time 126, and starts the signal generating circuit 4. Start signal generating circuit 4 Shin
Signal 122 indicating that there is no signal input to the data control circuit 2
a, 2b and the transmission line 9 via the transmission circuits 6a, 6b.
a and 9b.

A signal 122 indicating that there is no signal input
The repeater device 1b and the station 32 that have received the response signal 121 transmit a response signal 121. When the repeater device 1a receives the response signal 121 from the repeater device 1b, it recognizes that normal data transmission to the repeater device 1b is possible. However, there is no signal input output from the transmission circuit 6a.
For disconnection of the signal 122 is a transceiver cable 25a representing the bets, does not reach the station 31, the response signal 121 from the station 31 is not returned.

The repeater 1a does not return the response signal 121 even after a certain period of time, so the signal input is repeated.
A signal 122 indicating that there is no force is transmitted from the transmission circuit 6a. Signal 12 indicating that there is no retransmitted signal input
If the response signal 121 is not returned to the communication device 2, the repeater device 1 a activates the warning / display circuit 5 to display that the disconnection is detected, activates the data control circuit 2 b, and transmits the transmission circuit 6 b and the transceiver. The warning signal 124 is transmitted via the transmission line 9b of the cable 25c and the transceiver 24c. The repeater device 1b and the station 32 which have received the warning signal 124 can recognize the occurrence of the disconnection. Thereby, the operator of the station 32 can recognize the disconnection.

When a warning device such as a buzzer 35 is connected to the warning / display circuit 5 of the repeater device 1, the operator of the system can detect (transmit) the disconnection at an early stage.

In the above network system, after the operator recognizes the disconnection, repairs and inspects the location of the disconnection, a signal is input to the receiving circuit 7a or the collision detecting circuit 8a by normal data transmission, so that the timer 3a is reset. When the output of the warning signal from the signal generation circuit 4 is stopped, the normal operation is restored.

[0030] Figure 2 shows a circuit block diagram of an optical repeater unit according to a second embodiment of the present invention, FIG. 4 is an optical repeater unit is used is the <br/> second embodiment FIG. 6 is a system block diagram showing an example of a disconnection state (position) in the network shown in FIG. In the following description, one of the pair of optical repeater devices 41 will be referred to as an optical repeater device 41a,
The other is an optical repeater device 41b.

The optical repeater devices 41a and 41b transmit the signals output to the coaxial cables 21a and 21c to the transceivers 24a and 24b and the transceiver cables 25a and 25b.
A receiving circuit 7a for receiving via the receiving line 10a of 5b,
When the signals output to the coaxial cables 21a and 21c collide, the collision signals output from the transceivers 24a and 24b are transferred to the collision lines 1 of the transceiver cables 25a and 25b.
1a, a data control circuit 2a for relaying a signal received by the reception circuit 7a or the collision detection circuit 8a to the optical fiber side, and an electric signal input to the data control circuit 2a. An electro-optical conversion circuit 12 for converting the optical signal from the optical fiber 42b into an electric signal; A data control circuit 2b for returning a response signal when there is a signal input to the optical-electrical conversion circuit 13, and a transmission circuit 6a for outputting the signal to the coaxial cable side. timer 3a which is reset when there is an input and to change the monitoring time, 3b and, timer 3a, signal when there is no signal input exceeds the monitoring time set in 3b Signal and a signal input indicating that power is not
And a signal generating circuit 4 and the warning and display circuit 5 for no response outputs a warning signal when there is no response signal to the signal indicating that there is no.

The system using the optical repeater device 41 is connected to coaxial cables 21a and 21c and transceivers 22a and 22b and transceiver cables 23a and 23a.
A pair of optical repeaters 41a, 41b and an optical fiber 42a, between a station 31 and a station 32 located beyond the maximum transmission distance of the segment via 23b.
42b.

The operation of the optical repeater 41 during normal data transmission in a system using a pair of optical repeaters 41a and 41b will be described below. FIG. 8 is used as a time chart showing the operation of the optical repeater.
Light Repeater 41a repeaters 1a and 1b in FIG Oyo
And 41b. The data signal 120 transmitted from the station 31 is transmitted by the transceiver cable 2
3a, the transceiver 22a, the coaxial cable 21a, the transceiver 24a, and the receiving circuit 10a of the transceiver cable 25a, the signal is input to the receiving circuit 7a of the optical repeater 41a, and further input to the data control circuit 2a. The data control circuit 2a resets the timer 3a by inputting a signal, and the input signal is
Output to the optical fiber 42a via the optical conversion circuit 12,
The signal is sent to the opposing optical repeater device 41b via the electric / optical conversion circuit 12 and the optical fiber 42a.

In the opposing optical repeater device 41b, the light
The data control circuit 2b, to which the signal has been input via the electric conversion circuit 13, performs resetting of the timer 3b and transmission
a, output to the coaxial cable 21c via the transmission line 9a, create a response signal 121 to the reception of the data signal 120, and output the optical fiber 42a (42b in FIG. 4) via the electro-optical conversion circuit 12. And returns a response signal 121 to the optical repeater device 41a that is the transmission source.

When the data transmission amount is small (the data transmission interval is large) and the time 125 set in the timer 3a has expired, the signal generation circuit 4 is activated and the data control circuits 2a and 2b and the transmission circuit 6a , A signal 1 indicating that there is no signal input via the electric / optical conversion circuit 12
22 is a transceiver cable 25b and an optical fiber 42a
(42b in FIG. 4). No signal input
Optical repeater 1a that has received a signal 122 indicating that
And station 31 sends back a response signal 121, the optical repeater unit 1b can confirm that there is no abnormality in the transmission path and receiving the response signal 121. By confirming this response during normal data transmission , the pair of optical repeaters 1 can monitor each other.

[0036] All operations during disconnection and connector detachment of the connector disengaged and the coaxial cable connecting portion in the connection portion between open or optical repeater and the optical fiber of the optical fiber
Recovery operation after the preliminary breakage repair operation is the same as the detailed description of the repeater apparatus is omitted.

According to each of the above embodiments, no new line or power supply device is connected to the transmission line, so that the connector can be disconnected without increasing the possibility of disconnection and trouble such as line disconnection. A warning such as a line disconnection can be promptly displayed, and the detection of the trouble does not depend on the presence or absence of a signal to be relayed.

FIG. 7 is a circuit block diagram of a duplicated repeater device 51 according to a third embodiment of the present invention. The duplicated repeater device 51 is a device in which each circuit constituting the repeater device is duplicated, and converts the signal output to the coaxial cable into the transceiver and the receiving line 100 of the transceiver cable.
a, 100b or 101a, 101b, and a receiving circuit 70a, 70b or 71a, 71b, and a collision signal output from the transceiver when a signal output to the coaxial cable collides with a collision line 110a, Collision detection circuit 80a, 80b or 81 receiving via 110b or 111a, 111b
a, 81b and receiving circuits 70a, 70b or 71a,
71b, collision detection circuits 80a, 80b or 81a, 8
Data control circuit 2 for relaying and outputting the signal received by 1b
a, 2b, a transmission circuit 60a, 60b or 61a, 61b for outputting an input signal to the data control circuit 2a, 2b to a coaxial cable, and a transmission line 90a, 90b or 91.
a, 91b, and the data control circuits 2a, 2b
Timers 3a and 3b, which are reset when a signal is input to them so that the monitoring time can be changed;
When there is no signal input for more than the monitoring time set in b, the switching circuit 14 for switching between the transmission circuit, the reception circuit, and the collision detection circuit, and the warning / display circuit 5 are included.

The system using the duplex repeater device 51, as shown in FIG. 10, duplex repeater 5
2 is the same as the system configuration shown in FIG. 2 except that the transceiver cable and the transceiver connected to 1 are duplicated.

In a normal data transmission operation in a system using the duplicated repeater device 51, mutual monitoring by response confirmation is possible as in the case of the repeater device 1.

The operation at the time of disconnection at the connection between the duplicated repeater device 51 and the coaxial cable in a system using a pair of duplicated repeater devices 51 will be described below. When a disconnection occurs in the transceiver cable connected to the redundant repeater device 51, the receiving circuit 100
Since there is no signal input to a and the collision detection circuit 80a, the timer 3a is not reset even if the set monitoring time is exceeded, and the switching circuit 14 and the warning / display circuit 5 are activated.
The activated switching circuit 14 includes transmission circuits 60a and 61a,
Receiving circuits 70a, 71a and collision detecting circuits 80a, 8
The switch 14a for switching the output of 1a is activated. By this switching, the disconnected transceiver cable is disconnected and a normal transceiver cable is connected, so that data transmission can be continued. Further, since the warning / display circuit 5 is activated, it is possible to recognize a disconnection by connecting a buzzer or the like.

According to the present embodiment, the possibility of disconnection of the newly added cable or disconnection of the connector increases by duplicating the line. Recovery processing can be performed in a short time, and there is an effect that interruption time of data transmission can be minimized.

In the above-mentioned dual repeater device 51, if the timer 3a is not reset even if it exceeds the set monitoring time, the circuit is switched immediately. However, the signal generating circuit 4 shown in FIG. If the timer 3a is not reset even if it exceeds the set monitoring time, a signal input
It is also possible to first output a signal indicating that there is no response, and if there is no response signal to this, activate the switching circuit 14a to switch the circuit and activate the warning / display circuit 5.

[0044] Incidentally, the one connection portion between the two-way coaxial cable optical - electrical converter, electric - by the optical converter and the optical fiber can be a duplex optical repeater.

In each of the network systems shown in FIGS. 3 and 10, one pair of repeaters is used. However, depending on the length of coaxial cables 21a and 21c or the installation location, one repeater 1a may be used. and, the re <br/> repeater device directly to a transceiver cable 25a, 25
b, 25e, and 25f may be connected. In this case, when there is no response signal from the station, the repeater apparatus 1a displays a warning and switches the line.

[0046]

According to the present invention, the normality of the transmission line and the repeater device or the optical repeater device is confirmed by mutual monitoring by the response confirmation between the station and the repeater device or between the station and the optical repeater device or between the repeater devices. it can. Further, when a failure occurs due to a disconnection, the repeater device or the optical repeater device notifies the failure, so that a transmission line failure can be found early.

According to the redundant repeater of the present invention, when a failure occurs due to disconnection, the transmission path can be switched and data transmission can be continued without interruption, so that a highly reliable bus-type network system can be constructed.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing a configuration of a main part of a first embodiment of the present invention.

FIG. 2 is a circuit block diagram showing a configuration of a main part of a second embodiment of the present invention.

FIG. 3 is a diagram showing a bus-type network using the first embodiment of the present invention;
It is a block diagram showing an example of a network system .

FIG. 4 shows a bus-type network in which the second embodiment of the present invention is used.
It is a block diagram showing an example of a network system .

FIG. 5 shows a bus network in which a repeater device is used.
It is a block diagram showing an example of a disconnection position in over click system.

FIG. 6 is a bus-type net in which an optical repeater device is used.
It is a block diagram showing an example of a disconnection position in a work system .

FIG. 7 is a circuit block diagram showing a main configuration of a third embodiment of the present invention.

FIG. 8 shows a bus-type network using the first embodiment of the present invention.
Is a time chart showing a repeater operation in the normal over-click system.

FIG. 9 shows a bus network using the first embodiment of the present invention.
FIG. 4 is a time chart showing a repeater operation when the work system is disconnected.

FIG. 10 shows a bus-type device in which a third embodiment of the present invention is used.
FIG. 2 is a block diagram illustrating an example of a network system .

[Explanation of symbols]

 1, 1a, 1b Repeater device 2a, 2b Data control circuit 3a, 3b Monitoring means (timer) 4 Signal generation circuit 5 Warning / display circuit 6a, 6b Transmission circuit 7a, 7b Receiving circuit 8a, 8b Collision detection circuit 12 Electric-optical Conversion circuit 13 Optical-electrical conversion circuit 41, 41a, 41b Optical repeater device 51 Duplex repeater device

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hisayuki Maruyama 5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Omika Plant (56) References JP-A-2-56142 (JP, A) Kaisho 64-86639 (JP, A)

Claims (7)

(57) [Claims] 1. A a receiving circuit for receiving signals from the transmission path, and means for monitoring the signal input to the reception circuit, when there is no signal input beyond said <br/> set time to the monitoring means outputs a signal indicating that the signal input is not in the signal input
A signal generation circuit that outputs a warning signal when there is no response signal notifying that a signal indicating that there is no force is received ,
Means for warning or display that no said response signal,
Each have a plurality of a transmission circuit for outputting a transmission path a signal from the receiving circuit and a signal generating circuit, the signals from the signal and the signal generating circuit is input to the reception circuit transmission <br/> signal circuit And to the input to the receiving circuit
A bus-type network repeater device comprising means for returning the response signal . 2. A repeater according to claim 1, Oyo primary system circuit receiving circuit and a transmitting circuit having a plurality
Having each at least two circuits of the fine standby circuit, a switching circuit which is activated when there is no signal input exceeds the time set to the means for monitoring, the active system circuit or standby circuit by the output of said switching circuit A repeater device for a bus-type network, comprising: switch means for switching. 3. The repeater device according to claim 1, wherein at least one of the plurality of receiving circuits is an optical-electrical conversion circuit, and at least one of the plurality of transmitting circuits is provided.
One even without an electric - an optical conversion circuit, at least one transmission path, the repeater device of the bus type network, characterized in that an optical fiber. At least a pair of the repeater apparatus wherein connected by a transmission line, wherein a plurality of common transmission lines connected via at least one pair of the repeater device, and a station connected to said common transmission path In the network system, the repeater device is the repeater device according to any one of claims 1 to 3, wherein the other repeater device receives a response signal from one repeater device between the pair of repeater devices. A bus-type network system characterized in that a response is confirmed by reception. 5. A bus network system in which a plurality of stations are connected to a common transmission path and at least one pair of repeater devices according to claim 1 is used, wherein each of said repeater devices and The response signal described in 1
A bus-type network system , wherein the station having the means for returning includes a means for receiving a warning signal transmitted by at least one repeater device and detecting an abnormality. 6. A least one repeater device, the
A plurality of common transmission path connected via at least one repeater unit, in the common transmission path to the connected stations and the comprising at network system, the repeater apparatus repeater according to claim 1 or 2 Device returned from the station according to claim 5.
A bus type network system wherein a response signal is received by the repeater device to confirm a response. 7. The bus network system according to claim 1, wherein a plurality of stations are connected to a common transmission path, and at least one repeater device is used. A bus network system comprising means for receiving a warning signal transmitted by a repeater device and detecting an abnormality.