JPS5842982B2 - Remote transmission quality measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a data communication system that uses two or more data communication devices to exchange information via a line.
The present invention relates to a transmission quality telemetry method that can distinguish and detect failures in data communication equipment, lines, and terminals, and can measure low transmission quality of lines.

This type of conventional transmission quality measurement method is described in CCITT (International Telegraph and Telephone Consultative Committee) Recommendation V54,
As shown in the figure, the first
Loop test information (for example, CCITT SGX 1978.8
, Control & 120)
is sent to the line 13, the second data communication device 14 detects the loop test information, and uses this detected output to transmit the loop test information to the second data communication device 14.
A loop 16 (defined as loop 2 in CCITT Recommendation V54) at the interface between the data communication device 14 and the terminal 15 is set up to connect the first
A loop test information is configured from the first terminal 11, and the loop test information is transmitted from the first terminal 11 to the first data communication device 12.
By receiving the returned loop test information at the first terminal 11 via the line 13, the second data communication device 14, and the loop 16, a failure between the second data communication device 13 and the terminal 15 can be distinguished; Alternatively, the transmission quality between the first and second data communication devices 12 and 14 was measured.

That is, if the transmission quality is an error rate, the error rate from the first data communication device 12 to the second data communication device 14 is Pel, and the error rate from the second data communication device 14 to the first data communication device 12 is Pe2. Since the second data communication device 14 can be considered as a type of digital regenerative relay, the line error rate of the entire loop is Pe1+Pe2.

The method of receiving loop test information and forming loop 16 is, for example, as described in "Arashi 1s3 or A Study of Automatic Loopback System" in the March 1973 Proceedings of the General National Conference of the Institute of Electronics and Communication Engineers, or in Japanese Patent Application No. 59807-1983 (Special This can be carried out by the method described in the specification of JP-A-54-150907.

In this type of transmission quality measurement method, the service person maintaining the line and data communication equipment must carry a transmission quality measuring device to one terminal and perform the operations described above. It has been nearly impossible to reduce the labor and personnel costs of those involved.

In order to solve this drawback, the present invention provides a loop test information detection circuit and a loop setting circuit in the first and second data communication devices, and a switch circuit in the middle of the line between the first and second data communication devices. By inserting a third data communication device consisting of a loop test information generating circuit and first and second receiving circuits that receive the loop test information, failures can be detected and reduced at one location without having to dispatch service personnel to the terminal. It is designed to measure the transmission quality.

Generally, multiple data communication lines are bundled in the middle and housed in a station building, so if the third data communication device is switched and connected to each line at the station building, fault detection and transmission quality measurement can be performed for each line. can be done on one side.

FIG. 2 shows an example of a transmission quality measurement method according to the present invention, in which parts corresponding to those in FIG. 1 are given the same reference numerals.

A third data communication device 18 is inserted into the line 13 between the first data communication device 12 and the second data communication device 14 .

A switch unit 19 is provided in the third data communication device 18, and the switch S1. S2 is line 13
line 13a.

13b respectively in series, and the switches S1 and S
One end of each of switches 53tS4, S, and S6 is connected to both sides of the switch 2.

The third data communication device 18 further includes a loop test information generation circuit 21. High input impedance, low transmission quality receiving circuit 2
2. A transmission quality receiving circuit 23 whose input impedance is equal to the characteristic impedance of the line, and a computer 24 if necessary.
is provided.

Loop test information generation circuit 21, transmission quality reception circuit 22
and 23 are respective changeover switches S7. Switch S6. through S8 and S9. It is switched and connected to each other end of S3 and S6 and each other end of switch S, S6 and S3.

Like the second data communication device 14, the first data communication device 12 is also provided with means for detecting loop test information and setting a return loop 25 between the first terminal 11 and the first data communication device 12.

The loop 25 can be formed in the same manner as the conventional loop 16.

Measurement using this transmission quality measurement method can be performed as follows.

First, flip switches 87 to S9 to the left as shown by solid lines in the figure, and switch S5 p S3 + 8, respectively.
Connect to the 6 side and switch S□s S3 z 85 *
86 is ONL, and the other switches S2. S, is OF
Let it be F.

After setting in this manner, the loop test information generating circuit 21 sends out loop test information, for example, a code for controlling according to the method described in Japanese Patent Application No. 53-59807 (Japanese Unexamined Patent Publication No. 54-150907).

The first data communication device 12 receives this loop test information and sets up a loop 25 between the first terminal 11 and the first data communication device 12.

Next, the loop test information generating circuit 21 sends out loop test information for setting the loop 16 of the second data communication device 14 via the first data communication device 12.

The same loop setting information may be used for each loop setting.

After setting the loop 16 and loop 25 in this way, the loop test information generation circuit 21 further sends out the loop test information, and the transmission quality receiving circuits 22 and 23 receive the loop test information and count the transmission quality. .

As the loop test information in this case, random information similar to that used in normal low transmission tests can be used.

Now, assuming that the error rate is a measure of transmission quality, as shown in FIG.
Pe1 is the error rate that reaches the loop 25 from the loop 16 through the line 13b of the line 13, Pe2 is the error rate that reaches the loop 25 from the switch S2 to the loops 25 and 16.
Let e3 and Pe4 and the error rates from switch S1 to loops 25 and 16 be Pe5 and Pe6, respectively.

In the case of the previously set switch, the measurement error rate PeA of the loop test information receiving circuit 22 is Pe large, =Pe3+Pe5 (1).

Measurement error rate P e up to the loop test information receiving circuit 23
B is given by Pe5+Pe2+Pe5+Pe4(2).

Next, switches 87 to S9 are switched to the right side as shown by dotted lines in the figure, and switches s2, s3, etc. S4. Turn on S6
and other switches S1. Turn S5 OFF.

The same operations as in the case beyond the loop test information sending circuit 21 are performed to set the loops 16 and 25, respectively, and send out the loop test information.

As a result, the measurement error rate Pec in the loop test information receiving circuit 22 is P e O - P e 6 + P e4
(3), and the measurement error rate PeD in the loop test information receiving circuit 23 becomes PeD=Pe6+Pe2+Pe5 (4).

The above measurement results PeA, PeB, Pec. Pe)) is input into the calculator 24, and the following calculations are performed.

P e B - P e A+ P e D - P e
c=Pe1+Pe4- Pe5+Pe2+Pe5-P
e4=P e + P e 2 From these results, the error rates Pe1 to Pe6 of each part and the overall error rate Pe1+Pe2 can be measured, and the location of the fault can also be estimated.

In this way, it is possible to measure the error rate from one aspect without dispatching a service person to the terminal side.

In places where multiple data communication lines are bundled, the third
A data communication device 18 is provided, its switch section 19 is inserted into each line, and the loop test information generation circuit 21 and loop test information reception circuits 22 and 23 are switched and used in common. It is possible to measure the transmission quality and detect the location of faults for all these data lines at the location.

The calculation may be performed manually without providing the calculator 24.

As explained above, according to the present invention, by inserting the third data communication device into the line between the first and second data communication devices, the transmission quality of these line sections is measured, and the measurement results are calculated. Since the transmission quality can be determined, it is possible to measure the transmission quality between the first and second data communication devices by installing a third data communication device at one location and setting them at remote locations, and the measurement person can The advantage is that you don't have to go to the office.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional remote transmission quality measurement method, and FIG. 2 is a block diagram showing an example of the remote transmission quality measurement method according to the present invention. 11...First terminal, 12, 14...Data communication device, 13...Line, 15...
・Second terminal, 16°25...Loop, 18...
. . . Third data communication device, 19 . . . Switch section, 21 . . . Loop test information generation circuit, 2
2... Transmission quality receiving circuit with high input impedance, 23... Transmission quality receiving circuit with characteristic impedance, 24... Computer.

Claims (1)

[Scope of Claims] 1. First and second data communication devices each comprising means for detecting loop test information and means for forming a return loop based on the detection output of the detection means and setting the line in a loop test state. are connected via a line, and these first
, a data communication system in which information is exchanged between second data communication devices, wherein a third data communication device is provided between the line between the first and second data communication devices, and the third data communication device has the a loop test information generation circuit that transmits loop test information for loop test state setting and measurement; and a first transmission quality having a high input impedance that receives the loop test information via the first and second data communication devices. a second transmission quality receiving circuit terminated by a receiving circuit and a line characteristic impedance; a computer for processing transmission quality measurement data results; and loop test information from the loop test information generating circuit is transmitted from the first data communication device to a second data communication device. A path for transmission to the device and a path for transmission from the second data communication device to the first communication device can be set, and loop test information from the first and second data communication devices is transmitted to the first transmission quality receiving circuit. The loop test information from the first and second data communication devices can be set to
The loop test information generating circuit is provided with a switch section that can switch and set the path transmitted to the transmission quality receiving circuit.
A path consisting of a switch circuit - a first data communication device - a switch circuit - a second data communication device - a switch circuit - a first and second transmission quality receiving circuit is created by the switch circuit, and the loop test information is generated by sending the loop test information. The transmission quality is measured between the circuit and the first transmission quality receiving circuit, and at the same time, the transmission quality is measured between the loop test information generating circuit and the second transmission quality receiving circuit, and the loop test information generating circuit-switch A path consisting of the circuit - second data communication device - switch circuit - first data communication device - switch circuit - first and second transmission quality receiving circuits is created by the switch circuit, and the loop test information generating circuit is connected by sending loop test information. The transmission quality is measured between the loop test information generating circuit and the second transmission quality receiving circuit, and the transmission quality is measured between the loop test information generating circuit and the second transmission quality receiving circuit. A remote transmission quality measurement method, characterized in that a computer performs transmission quality measurement calculations between the first and second data transmission devices.