JPH0374990B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides a pseudo terminal for in-office equipment testing in the maintenance test system of digital exchanges, and for testing subscriber line/in-office equipment isolation in the event of subscriber system failure. It concerns the method of construction.

(Prior art) For maintenance tests on conventional digital switching equipment, see, for example, Shimakage and Sakaji, "Maintenance test method for digital subscriber systems" (Nippon Telegraph and Telephone Public Corporation Telecommunications Research Edition, Research and Practical Application Report, VOL.32). ，No.
11, 1983, P2461-2473). Hereinafter, a conventional maintenance test will be explained according to this.

In digital exchanges (exchanges whose networks are digitalized) that accommodate digital subscribers (subscribers who transmit digital signals on subscriber lines), it is necessary to check the normality of the exchange and disconnect faults between subscriber lines or terminals and the exchange. The different test items are: outgoing connection test (make a call to the network and check the network's operation in response to it); in-station call test (make a call to the network, make the call arrive at a terminal with a fixed method, and check the network's operation in response to the call); ), in-office incoming call test (calls are made from a fixed terminal, received via the network, and responded to).
Check the operation of the network and the continuity of the path. ), digital outgoing line testing (places a call to the outgoing line under test to the network and confirms network operation and path continuity), digital incoming line testing (calls from the incoming line under test are made) (Incoming and outgoing calls via the network, responding to the incoming calls, and confirming network operation and path continuity.) Digital trunk testing (initiating and receiving calls via the trunk under test) , network operation and path continuity), etc., and these tests require a function to simulate terminal operation (state transitions in call processing). A terminal device is mounted on a monitoring test rack and a remote monitoring test rack at a remote station.

As shown in FIG. 2, the exchange and the terminals consist of a main channel terminal M (here, a telephone) or a sub-channel terminal S (here, a non-telephone). It is connected to a network (NW), that is, an exchange 6 via an office side terminating unit (OCU) 4 and a line concentrator (LC) 5.
The subscriber line 3 is interfaced with digital signals, and the digital path is the section between the terminal side of the DSU 2 and the exchange side of the OCU 4, and the terminal interface has specifications defined by the T point. Therefore, when testing from the OCU 4 to the in-office equipment side, a test customer terminal unit (TDSU) 2' with the same configuration as the general subscriber DSU 2 is used, and a pseudo terminal (device) (DTIS) is used for testing. 1' is usually connected through the T-point interface described above.

Since point T is an interface between DSU 2 and terminal 1, there is a limit to the transmission distance. Therefore, when a remote station is installed, the pseudo terminal 1' must be mounted on the monitoring test rack of the master station and the remote monitoring test rack of each remote station.

In FIG. 2, the latter stage of the network 6 is connected to a signaling device (SIG) via the network 6.
7, or to a relay line 8 to other stations, but the signaling device 7 may be installed before the network 6 or before the concentrator switch of the concentrator 5, and if the signaling device 7 Even if the position is , it can be applied to the following explanation.

FIG. 3 shows a test configuration using conventional pseudo-terminals, including an in-office line concentrator 5 (representatively shown as one), a remote station 10 (for example, in the case of accommodating two stations). ) is accommodated in the master exchange 6.

Digital subscribers (one line is representative of those accommodated in each concentrator and remote station)
The terminal equipment (main channel, secondary channel) is DSU
2, and the interface between them is the T
point interface. DSU2 is subscriber line 3
It is accommodated in the OCU 4 of the master station or remote station. The interface between DSU2 and OCU4 can take various forms, such as two-wire time-division bidirectional transmission (ping-pong transmission), optical wavelength multiplexing transmission, etc.
If DSU2 and OCU4 are designed according to the transmission method, DSU2 will be used as TDSU2' as mentioned above.
can be used as is, and a pseudo terminal 1' matching the T-point interface can be provided, so the following explanation is also
It can be applied to any subscriber transmission system.

The OCU 4 passes through a line concentrator 5 (in the case of a remote station, a remote line concentrator 5' and a transmission terminal device (not shown),
(via a trunk line) is accommodated in the network 6.

In addition, OCU4 has a built-in retraction switch,
It can be disconnected from the subscriber line 3 and connected to the test line ITL. This is possible for any subscriber. The drawn-in test line ITL passes through a test space division concentrator switch 11 or 11',
The TDSU 2' is connected to the pseudo terminal 1' by a T-point interface.
In addition, a test line connected from OCU 4' with a fixed system to TDSU 2' in the same form as one terminal of a subscriber without going through a space division concentrator switch for testing.
There is also a DTL, which is also connected to the pseudo terminal 1' by a T-point interface.

FIG. 4 is a block configuration diagram showing an example of a pseudo terminal, in which the interface section TINF of TDSU2',
Level signal control unit LVL, code signal control unit COD,
Inch channel signal control section INCH, status control section STS, microprocessor toughace section
Consists of CPUINF and microprocessor CPU. The number of each section except the microprocessor CPU is the same as the number of TDSUs 2'. Note that the frame structure, test sequence, etc. shown below, including an example of the block structure in FIG. Not limited to,
It can be applied to any interface.

FIG. 5 shows the Y interface at point T, which is composed of an inch channel signal B, an out channel signal D, and a multiframe pattern F. The D bit has a multi-frame structure and includes a level signal and a code signal, and the level signal indicates a special state (calling, answering,
recovery, recovery confirmation, etc.), code signals are used to send and receive non-persistent control signals (progress display, dialing signals, etc.) to and from the signaling device of the exchange.

In the Y interface, the level signals are D ₁ , D ₁₁
The code signals are D ₃ , D ₅ , D ₇ , D ₉ ,
There are 8 bits: D ₁₃ , D ₁₅ , D ₁₇ , and D ₁₉ .

Note that the T point is a CMI code (a value of ``0'' represents the first half and second half of the time corresponding to 1 bit length as a low level and a high level, and a value of ``1'' represents the time corresponding to 1 bit length as a high level). The multi-frame information is interfaced with the CMI code (by breaking the alternation of the values of "1", The value of ``1'' at the point where the ration is inserted can be expressed at the same level as the value of ``1'' immediately before.). Other status signals mentioned above include the signal SV that indicates synchronization establishment and the signal OS that indicates that the _switch has stopped operating _.
~ _F20 is used to include two bits in the F bit.

The signals shown above, excluding multiframe information,
Setting/reading can be performed using I/O commands from the microprocessor CPU, and TDSU
It is also possible to set/read a signal S requesting power supply to 2' and a signal P indicating power supply.

In addition, the power supply request from the terminal to DSU2,
Power is supplied from the DSU2 to the terminal using the configuration shown in Figure 6, but the DSU2 is often used as the TDSU2', and in that case, the power supply request and power supply (power supply display) also depend on the terminal's circuit. Similarly, the configuration shown in the same figure will be used.

With the above configuration, the exchange can be tested, for example, an incoming call test (calls are made from the test line DTL to the specified test line ITL) to check the normality of the incoming sequence control and the relationship between the test line DTL and the test line ITL. The operation when performing a test to confirm the normality of the continuity of the initial path between the two terminals will be explained with reference to FIGS. 3 and 7.

When the test stand 14 sends a test command specifying the test item (internal call test), telephone number of the called subscriber, communication type (main/sub channel, signal speed, etc.), the test control device 13 or 13' is the drive of the retracting switch, the test space division concentrator switch 11
or 11', and transfers commands to the appropriate pseudo terminal 1' within the station where the subscriber to be tested is accommodated or of each remote station.

Commands to the pseudo terminal 1' in the station are transferred from the test stand control device 15 via the test control device 13, which controls the maintenance test equipment mounted on the monitoring test rack. Commands to the terminal 1' are sent from the test stand controller to the add/drop circuit 1 via a control link provided for controlling call processing.
2 to the test control device 13' of the remote station;
It will be transferred via there.

When the pseudo terminal 1' receives a command, it is analyzed by the built-in program and controls the outgoing sequence for the test line DTL, that is, the operation of the originating pseudo terminal shown in Figure 7, and the incoming call for the test line ITL. Sequence control, that is, the operation of the receiving side pseudo terminal shown in the figure is performed. In the case of an in-office call test, the called side is the test target, and the calling side is used as a testing tool.

In addition, the meanings of the symbols shown in parentheses in FIG. 7 are: L...level signal, C...code signal, S...
. . . Status signal, I . . . Indicates inch channel signal. The built-in microprocessor CPU sends/reads these signals according to the program, and compares them with the correct pattern. At the same time, it also monitors the time. When control from the network is not being performed normally, it is determined that there is an abnormality and the result is returned as an answer to the command.

(Problems to be Solved by the Invention) As mentioned above, the pseudo terminal has a built-in microprocessor to simulate the state transition of the terminal during call processing, and is large and expensive. There was a problem in that setting this separately for the master station and each remote station made the entire system extremely uneconomical. Also, remote stations,
Particularly when housing a portable box, installing large pseudo-terminals poses problems in terms of implementation, and in terms of control, test commands must be sent to each pseudo-terminal separately from the test control device. The problem was that it was complex and the processing load was large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for configuring a pseudo terminal that solves the above problems, is economical, easy to implement, and can reduce the burden on a test control device.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a method for configuring a pseudo terminal used for testing digital exchanges and digital subscriber lines, in which call processing is performed based on control of a microprocessor. A pseudo terminal body that simulates the state transition of the terminal in A digital communication channel and a digital line are connected between the terminal adapter and the pseudo terminal adapter to transmit and receive signals under test and control information.

(Function) According to the present invention, the part that simulates the state transition of a terminal in call processing is centralized under microprocessor control, and can be shared by a master station and a remote station.

(Example) FIG. 1 is a block diagram showing an example of a test configuration using the pseudo terminal (device) of the present invention, and the configuration of the exchange is the same as that used to explain the conventional configuration in FIG. It's the same. The steps from OCU 4 to subscriber line connection to TDSU 2' are also the same as those used in explaining the conventional configuration.

A pseudo terminal adapter 16 (second block) that interfaces with TDSU 2' through a T-point interface is installed near the TDSU 2', and the pseudo terminal (equipment) body 17 (first block) is used for the master station monitoring test. (It is only necessary to install one pseudo terminal equipped with the number of circuits required depending on the traffic conditions.)

FIG. 8 is a block configuration diagram showing one embodiment of the pseudo terminal of the present invention, in which the interface section TINF with the TDSU 2' is separated as a pseudo terminal adapter 16, installed near the TDSU 2', and the level signal control section LVL, code signal control unit COD, inch channel signal control unit INCH, status control unit STS, microprocessor interface unit CPUINF
and a microprocessor CPU are installed in the pseudo terminal 17. Although the same number of pseudo terminal adapters 16 as the TDSU 2' are provided, each part of the pseudo terminal main body 17 (excluding the microprocessor) only needs to have as many circuits as required by the test traffic, and a large number of remote line concentrators can be accommodated. TDSU if
This means that the number of units required is considerably smaller than that of 2'. Furthermore, regardless of the number of remote line concentrators, only one microprocessor CPU is required. The pseudo terminal adapter 16 has an interface section DTISINF with the pseudo terminal main body 17, and the pseudo terminal main body 17 has an interface section APINF with the pseudo terminal adapter 16.

Point A and point B in Figure 8 are connected only through a test time division concentrator switch in the case of an intra-office, but in the case of a remote concentrator, point A is connected to the master station pseudo terminal. The signal is placed in one or several time slots of the digital line between the remote concentrator and the master station by the add/drop circuit 12', passes through the transmission end station equipment, passes through the master exchange network, and then is inserted into the test time division concentrator switch. It comes to be connected to the pseudo terminal main body 17 at the later stage of 18.

Note that the test time division switch is already provided for switching various other digital signals of the monitoring test rack even in the conventional configuration, and is not newly required for the embodiment of the present invention. Further, the add/drop circuit 12' can be realized by only slight modification of the circuit provided as a control link for controlling a remote station in the conventional configuration, and thus does not impair economic efficiency.

FIG. 9 shows an example of the transmission format between point A and point B. In addition to the inch channel signal B, out channel signal D, multi-frame pattern FP, power supply request signal S, and power supply detection result P, - Checking the normality of transmission between point B, pseudo terminal device adapter return designation RT for testing, out-of-synchronization display signal HE, parity PY, parity error display PE, parity pseudo-normal designation DG, main/sub channel switching Specified CH etc. are accommodated. In addition, T
The point interface is a CMI code, and the frame pattern can be inserted as a violation, but since one or several time slots of the digital line are used between point A and point B, insertion as a violation is not possible. Therefore, the multi-frame pattern FP is separately provided as an independent fixed pattern, and F bits are separately provided for the signals _F2 to _F20 .

The operation when testing a switch according to this embodiment will be explained with reference to FIGS. 1 and 7, taking as an example the incoming call test described in the conventional configuration.

In response to a command from the test stand 14, the test control device 13 or 13' drives the retracting switch and the test space division concentrator switch 1, as in the case of the conventional configuration.
1 or 11', the test time division switch 18 is also connected, and commands are transferred to the pseudo terminal main body 17 (in the present invention, it is centrally installed in the master station). Since the command transfer destination is a centrally installed pseudo terminal,
There is no need for route division as in the case of the conventional configuration.

The operation of the pseudo terminal body 17 that receives the command is the same as in the conventional configuration. That is, the built-in program analyzes the command and controls the outgoing sequence for the test line DTL, that is, the operation of the originating pseudo terminal in the same way as shown in Figure 7, and the incoming sequence for the test line ITL. , that is, the operation of the receiving side pseudo terminal is performed in the same manner as shown in the figure. Here, all the circuits controlled by the microprocessor as I/O commands are concentrated in the pseudo terminal main body 17, so the level signals, code signals, status signals, inch channel signals, etc. are different from those in the conventional configuration. Similarly, sending/reading is performed according to the program, and comparison with the correct pattern is performed, and at the same time time monitoring is also performed to determine normality/abnormality. Note that since the standard time value (timeout value) in time monitoring is on the order of several seconds to several tens of seconds, the pseudo terminal main body 17 and the pseudo terminal adapter 16 are separated, and a digital communication path and a digital line are inserted between them. The time delay caused by this is not a problem.

(Effects of the Invention) As described above in detail, according to the present invention, an expensive microprocessor, microprocessor interface section, level signal, code signal, status signal, inch channel signal, and each control section can be centralized. Since it is placed only in the master station, it is expected to improve economic efficiency, and the remote station, especially when housing a portable box, can be made smaller.Furthermore, by centralizing the control interface, it is possible to improve the economy. This has the effect of reducing the processing load on the control device.

[Brief explanation of drawings]

The drawings serve to explain the present invention; FIG. 1 is a diagram showing an example of a test configuration using a pseudo terminal of the present invention, FIG. 2 is a diagram showing a connection between an exchange and a terminal, and FIG. Figure 3 shows a test configuration using a conventional pseudo terminal, Figure 4 is a block configuration diagram showing an example of a conventional pseudo terminal, and Figure 5 shows an interface between a conventional terminal and a home termination device. FIG. 6 is a diagram showing the power supply request and power supply relationship between the terminal and the home terminal equipment, FIG. 7 is a diagram showing the calling/receiving terminal sequence in the test, and FIG. FIG. 9 is a block configuration diagram showing one embodiment, and is an explanatory diagram of the format between the pseudo terminal adapter and the pseudo terminal main body. 1...Terminal (M...Main channel, S...Sub channel), 2...Delivery termination unit (DSU), 3...Subscriber line, 4...Office side termination unit (OCU), 5...Line concentrator Equipment (LC), 6...Network (exchange),
7...Signal device (SIG), 8...Relay line, 2'...
... Test home termination unit (TDSU), 16 ... Pseudo terminal adapter, 17 ... Pseudo terminal body, 18 ...
Test time division concentrator switch, 12'... Branch/add circuit.

Claims (1)

[Scope of Claims] 1. In a method for configuring a pseudo terminal used for testing digital exchanges and digital subscriber lines, A pseudo-terminal adapter is installed at the station and serves as an interface between the home terminal equipment and the main station and the remote line concentrator, and a digital communication path and digital circuit are established between the pseudo-terminal body and the pseudo-terminal adapter. A method for configuring a digital pseudo terminal, characterized in that the digital pseudo terminal is configured to be connected to transmit and receive signals under test and control information.