JPS58106940A - Interoffice continuity test system - Google Patents

Abstract

PURPOSE:To secure the bit integrity to a digital one-link call, by checking whether a bit train is received while preserved or not in a digital integrated network where the digital one-link connection is possible. CONSTITUTION:A test signal consisting of a specific bit string is transmitted from a testing circuit 19 stored in a preceding-level time division exchange A to a succeeding-level time division exchange B through a transmission line 15 and is turned back to the preceding-level time division exchange through the transmission line 15 by a turning-back circuit 10 stored in the succeeding-level time division exchange B. Normalities of up and down links are discriminated by the bit collation of transmitted and received signals in the testing circuit 19, thus securing the bit integrity to a digital one-link call.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inter-office continuity test method in a digital wire network that enables digital one-link connection.

l built mainly using analog technology for the purpose of voice communication
IE telephone networks are increasingly being used by local fishermen to communicate with non-telephone services such as data communications and facsimile communications, depending on the degree of development. Moreover, as various digital technologies advance, PCM transmission lines and time-division switching systems become economically viable, and it is expected that the digitalization of telephone networks will progress in the future. If a communication path can be formed only through the time division switch and the PCM transmission line, 64Kh/IO data communication will be possible and the communication time for data communication will be greatly shortened. However, since the telephone network is originally intended for analog voice signal communication, conventional continuity testing methods are insufficient for conducting continuity tests for data communication.

FIG. 1 is a diagram of a relay system when performing a conventional continuity test. In the figure, A is the originating local exchange (LS), B is the toll exchange (7'5), 1 and 8 are communication path switches, 2.9 is the communication path, 3 is the continuity test circuit, and 4 is the continuity test circuit. A subscriber line, 5, 12 controllers, 6, 7, 15.14 are control links, 10 is a return circuit, 11.15 is a transmission path, 16.17 is a common line link, and 1B is a calling telephone.

Now, when the telephone 18 makes a call, the reception/call analysis of the selected digits is performed using a public method, and the control device 15 of the exchange A selects the transmission line 15 of the corresponding outgoing route, and also sends the message via the common equipment link 16. The line number address etc. are transferred to the control device 12 of the relay exchange B. The common control device 5 is the transmission line 15
and the continuity test circuit 3 are connected by a communication path 2, and the common control device 12 connects the transmission line 15 and the return circuit 1o by a communication path 9. A common control device for three continuity test circuits [5] sends out an audible sound of frequency f as a signal via a control link 6 to the upstream side of the communication lotus 2. This town sound is input to the return circuit 10 via the transmission line 159 and the communication path 9. The return loop MIO returns the upstream signal to the downstream side as it is, and this audible sound is input to the tone receiver of the continuity test circuit 5 via the transmission path 151 and the communication path 2 on the downstream side of the communication path 9. .

If the paths are connected correctly, the tone receiver detects the audible tone and notifies the common control unit 5 on the control link 6. The results of the continuity test are notified to the downstream station B via the common line link 16. The conventional method described above is suitable for telephone communication because it guarantees that the communication path is closed, but in digital data communication, it also does not guarantee bit integrity that any bit string will be transmitted correctly. 712' is necessary and simply indicates that the communication path is closed.
□ is not enough. Namely.

In the conventional system, when an FDM line is selected as a relay line, a pad (P) is used for level adjustment even on a digital line.
AD) is inserted and pit integrity is not maintained, if one communication bus is closed and an audible sound shield signal is passed, it will be determined to be normal, so whether pit integrity is guaranteed or not. The problem is that it cannot be detected.

This is an important problem when configuring an integrated communication network that mixes analog switching equipment and digital time division switching equipment, as well as analog transmission lines and PCM transmission lines, and enables communication and digital data communication. It is what it is.

Also, after the tone receiver of the continuity test circuit 3 starts receiving an audible sound, it usually takes several tens of wgz to determine that there is a signal.
Since gc time is required, connection delay becomes a problem for data calls that require a short connection time. Moreover, tone receivers are generally constructed from digital signal processing circuits.

There are also problems with economics.

An object of the present invention is to eliminate the drawbacks of the conventional methods described above and to provide an economical continuity test method that can guarantee continuity including pit integrity when connecting one digital link.

The gist of the present invention is to perform an inter-office continuity test by transmitting a signal of a specific bit string via an exchange and a transmission line and checking whether the bit string is received while being preserved.

That is, a test signal of a specific bit string is sent from a test circuit housed in a preceding time-division switch to a subsequent time-division switch via a transmission line, and a loopback circuit accommodated in the subsequent time-division switch performs the test. By returning the signal to the upstream time-division switch via the transmission line, the normality of the upper and lower links is determined by checking the bits of the transmitted and received signals in the test circuit, and pit integrity for digital 1-link calls is determined. This guarantees that In this case, by using a test signal that includes a bit string obtained when digitizing signal components other than the analog frequency band assigned to telephone communications, it is possible to further ensure pit integrity. becomes.

The present invention will be explained in detail below using FIG.

FIG. 2 is a relay system diagram showing one embodiment of the inter-station continuity test system according to the present invention. In FIG. 2, numeral 19 is a digital continuity test circuit newly added according to the present invention, and is a 20-digit 64xb/# digital data terminal. Other symbols correspond to the symbols shown in the conventional system shown in FIG.

Now, when the digital data terminal 20 makes a call, the call is analyzed in the same way as in the conventional method and an outgoing route is selected, but since one sending terminal is a digital data terminal, the digital transmission path 15 is selected as the outgoing route. For the inter-office continuity test, the digital continuity test circuit 19 and the transmission line 15 are connected by a communication path 2, and the transmission line 15 and the return circuit 10 are connected by a communication path 9.

The digital continuity test circuit 19 sends a digital signal of a specific bit string to the communication path 2, and also sends a digital signal of a specific bit string to the communication path 2. Transmission line 15. Pass 9. Folding circuit 10. Pass 9. Transmission line 15
．． Pit comparison is performed with the signal returned via path 2, and a match or mismatch is notified to control device 5 via control link 6. If they match, it is determined that the continuity is normal, and the digital transmission line 15 for which the test has been completed is connected to the subscriber line 4, and data communication with the other party's terminal is performed. on the other hand,
If they do not match, select another digital transmission path,
Perform continuity test again.

Next m! Figures 1 and 4 show digital continuity test circuit 1.
The creation of No. 9 will be explained in detail. In Figure 5, 101U
32-bit parallel bit pattern generation circuit, 1
02r15 2-person car 1 output selector, 106 is a 5-bit counter, 104 is a 52-bit shift register, 10
5 is a comparator, 110 is a flip-flop, 112
is a 1-bit shift register. Also, 105,10
7 and 109H respectively 2mZ, 64KH1 and 8f/
/zo Cl ivy is generated with the phase relationship shown in FIG. 115 and 108 are 64 transmitted and received from the test circuit.
These are the output of Kb/z and large signal, and the check output of 111 t/i pit verification. The 64KbΔ output signal 113 is connected to the 64Kb/I input signal 108 on the output side of the communication path 2 shown in FIG.
is connected to the input side of the communication path 20. Also check output 1
11 is connected to the control link 6. counter 105t
d 2KIlz reset by clock 106, 64m
It is integrated by the X clock 107. Then, using 64xb/ as the ratio signal 115, as shown in FIG.
02 and are sequentially selected and output. On the other hand, the signals returned from the partner station are input to the shift register 104 from the 64xb/z input signal 108, and are sequentially shifted by the 64KBz clock 107. The output of the shift register 104 and the output of the bit pattern generation circuit 101 are compared and verified in units of 32 bits by a comparator 105, and when all bits match, the comparator 105 outputs an output. This output is outputted by the flip-flop 110 with a clock shifted by 1 bit from the 8ffz clock 109, and is 125 μsgty.
It is set every time. Therefore, if the pit integrity of the connection path is ensured, the check output 111 will indicate 2XI.
A pattern of 110001 is output in the iz cycle, but if pit integrity is not ensured, a pond pattern is output, so both continuity and pit integrity can be tested. In the above explanation, AO to A51
The bit string is not particularly limited, but 1, for example, 1K11z
It is also possible to select a PCM bit string corresponding to a sine wave of . In this case, the transmission line 15 is a lossy metallic line, or there is a level adjustment pad (pAD) on the way.
) is inserted and pit integrity is not maintained, this can be detected. However, if the M pit string is selected for a specific audible load, the transmission line is a digital transmission line but the opposite exchange is an analog exchange, and the level is adjusted correctly and an OdB path is formed. Even if there is code conversion in the middle, the original bit string may be returned. In this case, even though pit integrity is not ensured, this cannot be detected and a connection route via such an analog switch may be selected for data communication. Therefore, in the present invention, this problem was solved by selecting, as the test bit string, a bit string obtained by encoding an analog signal containing signal components outside the frequency band assigned to telephone communications. FIG. 5 shows an example of a bit string selected in this way, and FIG. 6 shows an analog waveform of this bit string. This bit string includes a 2KBz component.

'KfjZ, 8ffz... have large signal components.

o,an1z~3.4Klizic This is a bit string that cannot be generated from an analog signal that is limited in scope. Therefore, if there is an analog line, analog converter, etc. in the middle of the path, 0.5 to 5.4 Kf will be generated when decoding to an analog signal.
Since components other than lz are removed, this bit string is not regenerated. Therefore, it is always possible to detect that bit integrity is not maintained. Moreover, since bit verification is performed in units of 52 bits, the time required for one verification is Q, 125μIICX 4-Q, 5μtoe
hD, the time required for continuity testing can be significantly reduced compared to conventional methods.

As is clear from the above embodiments, according to the present invention, continuity testing including bit integrity guarantee for digital 1 link connection calls can be easily performed by simply providing a simple continuity test circuit and loopback circuit in the 11-split switch at the desired time. It is possible to do it on time.

Both performance and economy are significantly improved.

In one or more embodiments, a test circuit may be provided at the originating exchange.
In addition, we have explained the case where a test loop is set up by providing a return circuit at the relay exchange, but by providing a test circuit and a return circuit in all time division exchanges that accommodate digital data terminals, it is possible to set up a test loop for every 1 digital link call. It goes without saying that a test loop can be set up at the exchange facility.

This allows bit integrity to be guaranteed for each call.

[Brief explanation of the drawing]

FIG. 1 is a relay system diagram showing a conventional continuity test system, FIG. 2 is a relay system diagram showing an embodiment of the inter-station continuity test system according to the present invention, and FIG. 3 is a relay system diagram showing one embodiment of the inter-station continuity test system according to the present invention. FIG. 4 is a configuration diagram showing an example, and FIG. 4 is a diagram showing the phase relationship of the clocks in FIG. 3. FIG. 5 is a diagram showing an example of a bit string of a test signal according to the present invention, and FIG. 6 is a diagram showing an analog waveform corresponding to the bit string of FIG. A, B... switching office, 1, 8... communication path switch. 2.9...Communication bus, 5,12...Control device. 6.7, 15.14... Control link, 10... Return circuit, 11.15... Transmission line, 16.17.
・Common line link. 19...Digital continuity test circuit. 20...Digital data terminal. 1st country, 2nd gang, 5 tomoe, AyQ, 3rd, 4 mouths

Claims (1)

[Scope of Claims] 1. Send a test signal of a specific bit string to the upper syringe of the communication path of the time division switch, and receive the signal arriving from the lower link, A test circuit that performs verification and a return circuit that returns the received signal from the communication WRB link to the upper syringe while preserving its bit string are accommodated in the communication path of the time division switch, and are placed in front of the digital 1 link call. By connecting the test circuit of the time division switch and the return circuit of the downstream time division switch via the communication path switch of the upstream time division exchange, the interoffice transmission path, and the communication path switch of the downstream exchange, An inter-station continuity test method, characterized in that a loop is set up, the test signal is passed from the test circuit to the loop under test, and bit verification of transmitted and received signals is performed. 2. In the inter-office continuity test method described in claim 1, the test signal is obtained when an analog signal containing signal components outside the anarchic frequency band assigned to telephone communication is digitized. A NJ continuity test method characterized by using a signal containing a bit string.