JPH0548583A - Abnormality detecting device for data transmission line - Google Patents

Abstract

PURPOSE:To detect errors in a plurality of transmission lines quickly by installing the preambler generating circuit that generates mutually different preamblers and the preambler discriminating circuit that receives and discriminates individual preamblers. CONSTITUTION:Preambler discriminating circuits 7a, 7b, and 7c discriminate whether or not preamblers are those to be transmitted to transmission line 1, and since 7a, 7b, and 7c, discriminate that preamblers transmitted from transmission line 1 are normal since they are the preamblers generated by preambler generating circuit 5 and to be transmitted to the transmission line 1. However, in the 7c, since a system to be connected to transmission line 1 is actually connected to transmission line 2, the system receives preamblers generated by preambler generating circuit 6, and since they are different from preamblers to be transmitted to transmission line 1, and the error detecting device informs the occurrence of abnormality by means of alarm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission line abnormality detecting device in a data transmission system having a plurality of transmission lines.

[0002]

2. Description of the Related Art Generally, in order to improve the reliability of data transmission, a data transmission system has a plurality of transmission stations connected to two or more transmission lines, one of which is normally used and the other of which is normally used. The standby system is used when an abnormality occurs in the regular transmission line. When an abnormality occurs in the regular transmission line for some reason, the data transmission system switches to the standby transmission line and transmits data to a plurality of transmission stations using the same transmission line.

Since the above data transmission system is provided with two or more transmission lines, a large number of various parts such as a coaxial cable, a connector, a cable tap, a repeater, and the like are required. I was afraid.

However, even if the wirings are crossed due to a work error, the same data is transmitted to the standby transmission path, so that each transmission station on the receiving side can receive the data. However, when an error occurs in the regular system and when switching to the standby system, if all transmission stations are switched to the same transmission line, all transmission stations cannot be connected to the same transmission line due to wiring mistakes and data will be transferred. There was a fear that I could not receive it correctly.

In the conventional method for detecting the abnormality of the transmission line due to the above wiring error, the staff member has to examine two or more transmission lines, and it is not easy to detect the wiring error promptly. Therefore, in the conventional peripheral storage device, the NRZI
(Non-return-to-zero change
e on1) cannot be synchronized for each track, so
Data is written in a format such that at least one "1" bit exists in one column, and the phase shift of the other track from the bit with the most advanced phase among "1" existing in one column. By taking the delay time assumed to be absorbed, a clock common to all tracks is created. Therefore, if the skew (phase shift between tracks) is large to some extent, it cannot be used and the practical recording density is at most 32.
rpmm (800 rpi). In addition, PE (pha
Since it is possible to synchronize each track, it is more suitable for high density than NRZI. However, in practice, a preamble (consisting of 40 consecutive "0" s) is written at the beginning of the block. VFO (variabl) provided in a multi-tone system using the read signal of the part
e frequency oscillating) operation is started, and a clock for synchronizing data that appears after the preamble is created. VFO is an excellent method that follows a long period speed fluctuation well, and is also used in other magnetic storage devices. And 246 rpmm (6250 rp
i) GCR (group code) used for
d recording) adds one redundant bit for each successive 4 bits and performs code conversion and writes it on the tape. Even if the codes after conversion are arranged in any combination, at most two "0" s are consecutive. Therefore, as with PE, synchronization can be achieved for each track, and the maximum magnetization reversal density is lower than that of PE, which is advantageous for higher density.

Next, in time division multiplexing, each digital signal to be multiplexed is cyclically arranged, a pulse having a specific pattern (this is called a frame synchronization pulse) is pushed in every cycle, and this 1 cycle The minute is called a frame, and the receiving side detects the frame synchronization pulse and identifies the time slot of each multiplexed digital signal based on this, and this is called frame synchronization. Assuming that a 4-bit sync pulse of "1011" is arranged at the beginning of one frame, the process from the state where the frame is out of sync to the time of synchronization is set to d for the input code sequences a to i. The positions a to d are inspected, and the positions are sequentially shifted to the positions e, f ... to see if they match the frame sync pulse train. When the position i is reached, the sync pulses match.
However, it may happen that the pulses coincide with each other, so it is checked whether or not the sync pulse exists at the same position for the following several frames (backward protection). On the other hand, if the frame synchronization pulse is not synchronized and the frame synchronization pulse does not match, a code error on the transmission path may have occurred, so the synchronization will be lost only after N consecutive mismatches. Then, it shifts to the synchronous recovery operation (forward protection). When the value of N is large, the probability of miss frame is reduced, but since synchronization recovery is delayed when synchronization is truly lost, N is determined in consideration of both balances. Generally, the value of N is around 5.

[0007]

In the conventional data transmission line abnormality detection method, when an abnormality occurs due to a wiring error in the transmission line, a staff member must sequentially examine a plurality of transmission lines to detect a wiring error. However, there is a problem in that it takes time to detect a wiring error, resulting in deterioration of system functions.

The present invention has been made in view of the above, and an object thereof is to transmit a frame in which each preamble is added to a plurality of transmission lines at the time of transmission, and to receive the preamble at the time of reception. When it is abnormal by judging whether it is a frame of its own system, an alarm is generated,
An object of the present invention is to provide an abnormality detection device for a data transmission line that immediately detects a wiring error.

[0009]

According to the present invention, there is provided a first transmission station connected to a data terminal device for controlling input / output of data and controlling modulation / demodulation of data, and a transmission side terminal of the first transmission station. A first preambler generation circuit connected between the first transmission lines and adding a first preambler of the transmission data, and connected in series with the first preambler generation circuit to transmit the transmission data and the first preambler A second driver circuit, a second preambler circuit connected between the transmission-side terminal of the first transmission station and the second transmission line, and adding a second preambler different from the first preambler; A second pre-ambler connected in series with the pre-ambler generation circuit for transmitting transmission data and a second pre-ambler;
A driver circuit, a first receiver circuit connected to the first transmission line to receive the transmission data and the first preamble, and a first preambler connected in series to the first receiver circuit for determining the first preambler A determination circuit, a second receiver circuit connected to the second transmission line to receive the transmission data and the second preamble, and a second preambler connected in series to the second receiver circuit for determining the second preamble A determination circuit, and a second preamble determination circuit and a first
An abnormality detecting device for a data transmission line, comprising: a reception switching circuit that switches an output circuit of a preambler determination circuit to connect to a reception side terminal of a second transmission station.

[0010]

In the data transmission path abnormality detecting device of the present invention, the first transmission station is connected to the data terminal device to control the input / output of data and control the modulation / demodulation of data.
A first preambler of the transmission data is added by connecting between the transmission side terminal of the first transmission station and the first transmission line,
The driver circuit transmits the transmission data and the first preamble, and the first preamble generator generates the first preamble.
A second preamble different from the preamble is added, transmission data and second preamble are transmitted by the second driver circuit, transmission data and first preamble are received by the first receiver circuit, and first preamble determination is made. The circuit determines the first preamble, the second receiver circuit receives the transmission data and the second preamble, the second preamble determination circuit determines the second preamble, the second preamble determination circuit, and the first preamble determination circuit The output circuit of the preamplifier determination circuit is switched and connected to the reception side terminal of the second transmission station to detect an abnormality in the data transmission line.

[0011]

EXAMPLE An example of the present invention will be described below. FIG. 1 shows a transmission station 3a that is connected to a data terminal device to control input / output of data and controls modulation / demodulation of data, and is connected between a transmission side terminal Tx of the transmission station 3a and a transmission line 1 to transmit transmission data. A preambler generation circuit 5 for adding a preambler Pa, a driver circuit 9 connected in series with the preambler generation circuit 5 for transmitting transmission data and a preambler Pa, a transmission side terminal Tx of a transmission station 3a, and a transmission line 2 A preambler generation circuit 6 connected between the preambler Pa and a preambler Pb different from the preambler Pa; a driver circuit 10 connected in series with the preambler generation circuit 6 to transmit the transmission data and the preambler Pb; A receiver circuit 11b connected to the path 1 to receive the transmission data and the preambler Pa, and a receiver circuit 11b. A preambler determination circuit 7b that is connected in series to determine the preambler Pa, a receiver circuit 12b that is connected to the transmission path 2 to receive the transmission data and the preambler Pb, and a preambler that is connected in series to the receiver circuit 12b. Preambler determination circuit 8b for determining Pb
And a reception switching circuit 4b for switching the output circuits of the preambler determination circuit 7b and the preambler determination circuit 8b to connect to the reception side terminal Rx of the transmission station 3b. In the data transmission path abnormality detection method for detecting an abnormality of a plurality of transmission paths in a data transmission system having a plurality of transmission paths, a different preamble is added to each of the plurality of transmission paths during transmission, An apparatus for detecting an abnormality in a data transmission line, comprising means for detecting an abnormality in a plurality of transmission lines by determining whether or not the received preamble is a self-system preambler during reception.

In the embodiment of the present invention, a plurality of transmission paths are provided on the transmission side, and a preambler generating circuit for generating each preambler and whether or not this preambler is a preambler of its own system are determined. For this purpose, a preamble determination circuit provided on the receiving side for each of a plurality of transmission lines is provided, and in the abnormality detection method of the data transmission line having the above configuration, different preambles are provided for each transmission line. By transmitting, the receiving side determines whether or not the data frame is a data frame of its own system and detects anomalies in a plurality of transmission paths, so that anomalies in the transmission paths can be quickly detected.

Referring to FIG. 1, in the data transmission abnormality detection method, the transmission line 1 is connected to the reception switching device 4a via a receiver 11a and a preambler determination circuit 7a.
The transmission line 2 is connected to the reception switching device 4a via a receiver 12a and a preambler determination circuit 8a.

The reception switching device is a transmission station 3a.
Is connected to the reception terminal Rx of the transmission controller.

The transmission terminal of the transmission controller of the transmission station 3a is first connected to the transmission line 1 via the preambler generation circuit 5a and the driver 9a, and secondly to the transmission line 2 via the preambler generation circuit 6a and the driver 10a. It is connected.

Similarly, the reception terminal Rx of the transmission controller of the transmission station 3b is connected to the reception switching circuit 4b to the transmission line 1 via the preamble determination circuit 7b and the receiver 11b, and the preamble determination circuit 8b and the receiver 12 are also provided.
It is connected to the transmission line 2 via b.

The reception terminal Rx of the transmission controller of the transmission station 3c is connected to the reception switching circuit 4c,
It is connected to the transmission line 2 through the preambler determination circuit 7c and the receiver 11c. The receiving circuit 4c includes
The transmission line 1 is connected via the preambler determination circuit 8c and the receiver 12b.

The transmission controllers of the transmission stations 3a to 3c control transmission of the transmission stations, and the reception switching devices 4a to 4c switch reception of data transmitted from the transmission lines 1 and 2. The receivers 11a, 11b, 12c receive data from the transmission line 1, and the receivers 12a, 12b, 11c
Is a device that receives data from the transmission path 2. The driver 9 is a device that transmits the data transmitted from the transmission terminal Tx of the transmission controller of the transmission station 3a to the transmission line 1, and similarly, the driver 10 is a device that transmits the data to the transmission line 2.

The preambler generation circuit 5 is a circuit for generating a preambler for the transmission line 1. Each preambler generation circuit to be connected to the transmission line 1 generates a preambler as shown in FIG.

The preambler generation circuit 6 is a circuit for generating a preambler for the transmission line 2. In each preambler generation circuit connected to the transmission line 2, a preambler generated by the preambler generation circuit 5 connected to the transmission line 1 is used. Is a circuit for generating a different preamble, for example, as shown in FIG.

Preambler decision circuits 7a, 7b and 7c are circuits for deciding whether or not the preamble is to be transmitted to the transmission line 1, and 7a and 7b are preambler generation circuits for the preamble transmitted from the transmission line 1. Since the preamble is generated by the transmission path 1 and is to be transmitted to the transmission path 1, it is determined to be normal and no operation is performed. But in 7c,
Since the system to be connected to the transmission line 1 is connected to the transmission line 2 due to a wiring mistake, the preamble generation circuit 1
Receives the preamble generated by 0, which is
Since the preamble to be transmitted to the transmission line 1 is different from that described above, an alarm is generated or a transmission controller is notified, for example, to notify the abnormality.

Similarly, the preamble determination circuits 12a and 12a
Since b receives the preambler to be transmitted to the transmission line 2, it does not operate, and 12c does not transmit because the system to be connected to the transmission line 2 is connected to the transmission line 1 due to a wiring error. Preambler decision circuit 1 connected to path 1
2c warns of abnormality.

As a result, immediately after starting the data transmission after the wiring process, the normal abnormality can be immediately confirmed, and the wiring error can be surely detected.

FIG. 2 shows an example of the preambler Pa and FIG. 3 shows an example of the preambler Pb.

[0025]

As described above, according to the present invention,
Different preambles are transmitted by the preambler generation circuit for each of multiple transmission lines, and the preamble determination circuit can detect abnormalities in multiple transmission lines quickly, thereby preventing system function deterioration and maintaining maintenance costs. Can be suppressed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an abnormality detection device showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a preambler.

FIG. 3 is an explanatory diagram showing another preambler.

[Explanation of symbols]

 1, 2 ... Transmission lines 3a, 3b, 3c ... Transmission station 4 ... Reception switching circuit 5, 6 ... Preambler generation circuit 7b, 8b ... Preambler determination circuit 9, 10 ... Driver circuit 11a, 12b ... Receiver circuit

Claims (1)

[Claims] 1. A first transmission station connected to a data terminal device to control input / output of data and control modulation / demodulation of the data, and between a transmission side terminal of the first transmission station and a first transmission line. A first preambler generation circuit connected to add the first preambler of the transmission data, and a first driver circuit connected in series with the first preambler generation circuit to transmit the transmission data and the first preambler A second preamble generation circuit connected between the transmission side terminal of the first transmission station and a second transmission line to add a second preamble different from the first preamble, and the second preamble generation. A second driver circuit connected in series with a circuit for transmitting the transmission data and the second preamble, and the transmission data and the second driver circuit connected to the first transmission path. A first receiver circuit for receiving a first preamble, a first preambler circuit connected in series to the first receiver circuit for determining the first preambler, and a first receiver circuit connected to the second transmission line A second receiver circuit for receiving the transmission data and the second preamble, and the second receiver circuit connected in series to the second receiver circuit.
A second preamble determination circuit for determining the preamble,
An abnormality detecting device for a data transmission line, comprising: a reception switching circuit that switches the output circuit of the second preamble determination circuit and the output circuit of the first preamble determination circuit to connect to the reception side terminal of the second transmission station.