JPH0750908B2 - D channel extraction / insertion circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] A circuit for extracting / inserting a D channel of a digital subscriber accommodated in a line concentrating circuit in a digital switching system, and accurately performing a function of extracting and transmitting control data in the digital switching system For the purpose of providing a D channel extracting / inserting circuit capable of performing D channel extraction / insertion circuit, each input side highway and output side highway of the digital concentrator circuit is provided with an extraction circuit and an insertion circuit for D channel data, and a test lead-in circuit is provided as described above. It is installed between the highway extraction circuit, the insertion circuit and the digital subscriber line circuit controller, and it inputs / outputs to the test pull-in circuit.
The data of the channel is connected to the B channel of the specific channel of the subscriber line for the test lead-in in the subscriber line, and the specific channel is connected to the designated channel for the maintenance device through the digital concentrator circuit and is connected to the maintenance device. It is configured to transmit / receive D channel data to / from the subscriber line.

[Field of Industrial Application] The present invention relates to the extraction and extraction of D channels of digital subscribers accommodated in a line concentrator circuit in a digital switching system.
Regarding insertion circuit.

In recent ISDN (Integrated Services Digital Network), each terminal including a telephone is connected to a switchboard by digital signal. That is, an efficient large-scale information communication network is formed by treating a digital telephone as one terminal device together with a digital communication device such as a facsimile and a personal computer in a telephone subscriber's house.

In a conventional telephone exchange using an analog telephone, the subscriber line is pulled into the maintenance device for the purpose of inspection during system construction, maintenance inspection during system operation, testing, etc. Was being inserted into the subscriber line.

In a large-scale information communication network, an information signal channel (called B channel) and a control signal channel (called D channel) are separated, and the D channel of a subscriber line (including terminal equipment) is separated. Realization of an extraction / insertion circuit for maintenance and inspection is desired.

[Prior Art] FIG. 3 shows a conventional system configuration diagram of a digital switching system of a large-scale information communication network.

In the figure, 40 is a digital telephone, 41 is a terminal controller (TCE: Te
rminal Control Equipment), 42 is a network terminal equipment (NTE: Ne
twork termination equipment), 43 is a digital subscriber line circuit (DLC), 44 is a digital subscriber line circuit controller (DLCC: Digital Line Circ)
uit Controler), 45 is a line time switch (LTSW: Line
Time Switch), 46 Digital Line Interface (DLIF), 47 Line Processor (LPR), 48 Network (NW), 49 Central Processor (CPR), 50
Is a console for maintenance (CNS: Console for Maintenance)
Is.

In a conventional analog telephone, the digital subscriber line circuit 43
Is a subscriber circuit (SLC) that operates on analog signals, and an analog telephone is connected to the subscriber circuit through a telephone line, where A / D conversion is performed and a digital voice signal is guided to the line time switch 45. . In addition, when a call is made from an analog telephone, a loop is formed by off-hook, and the switching side detects this loop current by scanning to make a distinction.However, in a digital telephone, the control data such as call / call is voice data. Similarly, the terminal side and the concentrator circuit (Fig. 43 ~
47 is called a concentrator circuit) and is transmitted / received in a packet, and the state is notified.

The line time switch 45 exchanges information with the central processor 49 of the network 48 to control which of the output channels of the line time switch 45 is connected to which of the input terminals of the network 48. Since the digital telephone sends the connection information such as the other party's telephone number in the D channel of the packet, the DLC43 takes this out, and the DLCC44, DLI
Send to LPR47 via F46. LPR47 receives this and performs the above-mentioned connection control. The DLCC44 and DLIF46 are also not found in analog type exchanges.

In the network 48, the highways of a plurality of concentrators are accommodated, and in order to communicate between the highways, exchanges are performed under the control of the CPR49 by exchanging control signals with each LPR,
A connection (by channel) is formed within the own station or through a network of another station via a trunk line, and information is transmitted.

In such a large-scale information communication network such as ISDN, terminals such as digital telephones (including facsimiles and personal computers)
Between the switch and the exchange, communication information and various control information including outgoing / incoming calls are transmitted and received in packets.

At that time, as shown in the lower left of FIG. 3, a channel of 64 Kbps (this is called B channel) is usually used for communication information.
Two channels of 0 and B1 and one channel of 16 Kbps for control information (D channel) are used (two bits of D0 and D1), which is called 2B + D system. This 2B + D channel configuration is provided in the up (up) and down (down) directions, respectively.

[Problems to be Solved by the Invention] Usually, in a telephone exchange system, it is possible to inspect whether each subscriber line is operating normally, or to test whether it has been repaired at the time of abnormality but returned to normal. This is a required function. In that case, the required test is performed by pulling in the subscriber line to be tested (or checked) by operating the maintenance console of the exchange. However, in the case of the conventional analog telephone, which can be easily realized by electrically connecting the lines, the same technique is applied to the subscriber line which transmits the digitized and packetized information. I can't.

In addition, it is necessary to perform monitoring, testing, etc., of the plurality of channels on one subscriber line, especially the control channel (D channel), while good extraction /
There was no insertion circuit. That is, various tests such as monitoring the status of the digital telephone (or other digital terminal), checking whether the control data is normally generated, sending control data indicating an incoming call from the console to check the status, etc. It is required to carry out tests and inspections.

SUMMARY OF THE INVENTION An object of the present invention is to provide a D channel extracting / inserting circuit capable of precisely performing the function of extracting and transmitting control data in a digital switching system.

[Means for Solving the Problem] FIG. 1 (a) shows a basic configuration diagram of the present invention, and DLC (digital subscriber line circuit) and LTSW in the configuration of the conventional example of FIG.
The block diagram of the structure newly provided between (line time switch) is shown, and other parts are the same as that of a prior art example.

In FIG. 1 (a), 10 is an extraction circuit (dropper) D, 11 is an insertion circuit (inserter) I, 12 is a test pull-in circuit (a portion surrounded by a dotted line), 20 is a line time switch LTSW, and 21 is a maintenance device. Represents

Lines 100 and 110 in the figure represent an upstream subscriber line and a downstream subscriber line for one subscriber, and a test lead-in circuit 12 is a pull-out circuit.
It is composed of 13,17,18, insertion circuits 14,16,19, and multiplex circuit 15, and has terminal number P1 as a subscriber line for test lead-in.
5 downlink and uplink lines 180 and 190 are used.

FIG. 1 (b) shows a bit accommodation diagram (uplink channel) of a specific channel set as a dedicated line (B channel) for connecting to a maintenance device according to the present invention, and bits 1 and 5 to a downlink subscriber line. The contents of the D channel that is sent out,
Bits 2 and 6 are the contents of the D channel extracted from the upstream subscriber line.

According to the present invention, a downlink channel and an uplink channel are separately extracted and inserted into the digital concentrator circuit section, and an insertion circuit is provided to secure beforehand D channel control data from a subscriber and control data from the concentrator control circuit to the subscriber. It is inserted in the specified channel and transmitted by the dedicated B channel and drawn into the maintenance line. Conversely, when control data is sent from the maintenance line to the downlink subscriber line and control circuit of the concentrator, it is extracted from the specified downlink channel, and the control data to the subscriber line and control circuit are separated and the downlink subscriber is separated. It is intended to be inserted into lines and lines to control circuits.

[Operation] Each of 2B + D channels of the upstream subscriber line 100 is the extraction circuit 1
When the D channel (2 bits) is extracted at 0 and no test is performed, the DLCC (digital subscriber line circuit controller of FIG. 3) which is the control unit of the concentrator is directly used.
44).

When performing a test, the extraction circuit 13 extracts the data of the D channel from the bit positions 2, 6 of the specific channel in FIG. 1 (b).
And is multiplexed by the multiplexing circuit 15. On the other hand, the control data sent from the DLCC to the downlink subscriber line 110 of the subscriber (passes the extraction circuit 17 and the insertion circuit 16 when the test is not performed) is extracted by the extraction circuit 17 when the test is performed. 2 bits are multiplexed in the multiplexing circuit 15 and the extraction circuit 13
Is multiplexed with the output of.

The structure of the data multiplexed by the multiplexing circuit 15 is shown in FIG. 1 (b).
Bits 1 and 5 are downlinked (sent from DLCC to subscriber)
Control data, bits 2 and 6 go up (from subscriber to DLC
Send to C) control data.

The multiplexed data shown in FIG. 1 (b) is obtained by connecting the terminal (P1) of the upstream line 190 of the particular subscriber of the line time switch 20.
It is inserted from the insertion circuit 19 into the specific channel assigned to 5). This specific channel is used only for test pull-in,
Two pieces of D channel information multiplexed as information data (B channel) of the specific channel are transmitted, and reach the network (see 48 in FIG. 3) from the line time switch 20 via the voice highway to maintain the network. It is pulled into the channel of the device 21 and informs the maintenance person of the contents.

The data shown in FIG. 1 (b) is then sent from the maintenance device 21 as it is to the network through a specific channel.
Through the audio highway, the LTSW 20 appears on a specific channel assigned to the terminal (p15) of the down line 180 of the specific subscriber line, and is extracted from the extraction circuit 18 to output bits 1 and 5 of FIG. 1 (b). It is inserted in the insertion circuit 16 for transmission to the downlink subscriber line, and bits 2 and 6 are inserted in the insertion circuit 14 for transmission to the DLCC.

In this way, both the upstream and downstream control data extracted for sending to the maintenance device first are returned to their original positions.

In this case, the maintenance device can monitor the exchange of control data between the terminal and the exchange, and in the maintenance device 21, the maintenance person creates control data from the operation panel and sends the control data to the subscriber line. By checking the control data transmitted from the terminal, various functional tests of the terminal such as a digital telephone can be executed. For example, it is possible to test the function of the communication protocol and the call origination / termination call.

[Embodiment] FIG. 2 shows a configuration diagram of an embodiment of the present invention.

In FIG. 2, 23 and 34 are demultiplexing circuits (DMPX)), 24, 30 and 33 are serial-parallel conversion circuits (S and PCV), 2
5,29 is 2-bit, 32 is 8-bit latch circuit (displayed by FF), 26,28,35 to 37 are multiplex circuits (displayed by MPX), 27,31 are parallel-serial conversion circuits (P / SCV), 38 is a line time switch, 39 is a timing generator, and 100 and 110 are upstream subscriber lines and downstream subscriber lines.

In this embodiment, a demultiplexing circuit (DMPX) and a serial / parallel conversion circuit (including a latch circuit) constitute an extraction circuit, and a multiplexing circuit or a parallel / serial conversion circuit and a multiplexing circuit constitute an insertion circuit. Needless to say, it can be configured using a conventionally known extraction circuit (dropper) or insertion circuit (inserter).

When the maintenance person specifies the channel to be pulled in from the maintenance device, DL is sent via CPR (49 in FIG. 3) and LPR (47 in FIG. 3).
The timing generator 39, which is transmitted to the CC (Digital Subscriber Line Circuit Controller) and controlled by the DLCC, accordingly generates the signal T1 at the timing when the corresponding channel appears. As a result, two bits of the D channel output from the demultiplexing circuit 23 are input to the serial-parallel conversion circuit 24, and the control data converted in parallel is latched by the latch circuit 25. on the other hand,
Downlink control data output from the DLCC is converted in parallel by the serial-parallel conversion circuit 30 and latched in the latch circuit 29. Then, the outputs of the latch circuits 25 and 29 are multiplexed by the multiplexing circuit 26 and then supplied to the multiplexing circuit 28 from the parallel-serial conversion circuit 27 by the timing signal T3 corresponding to the B channel of the pull-in test specific channel. This multiplex circuit 28 uses the timing signal T4 (designated channel for maintenance device)
Output to 38.

The transmitted B channel data of the specific channel is pulled into the maintenance channel assigned to the maintenance device (21 in FIG. 1 (a)) and received, and transmitted from the D channel data on the subscriber line 110 and from the DLCC. The status can be checked by receiving the control data (see FIG. 1 (b)).

This received data is given as it is from the maintenance device to the LTSW 38 through the network and is output to the B channel of the downlink of the specific channel. The output is a demultiplexing circuit
A specific channel is taken out at 34, converted to parallel data at the serial-parallel conversion circuit 33, and loaded into the latch circuit 32. Downstream control data (first and fifth bits in FIG. 1 (b)) among them is transmitted to the B channel of the subscriber from the LTSW 38 in the multiplexing circuit 36 via the multiplexing circuit 37 and the inserting circuit (not shown). And is transmitted to the downlink subscriber line 110.

The upstream control data of the latch circuit 32 (the second and sixth bits in FIG. 1B) are multiplexed by the multiplexing circuit 35 and sent to the DLCC.

Next, if the maintenance person of the maintenance equipment wants to insert control data for monitoring or testing, first remove the channel to be inserted, create the desired control data on the previously secured channel, and send it out. The control data is sent to the maintenance device and the control data sent from the subscriber is extracted and sent to the maintenance device.

EFFECTS OF THE INVENTION According to the present invention, it is possible to arbitrarily set the contents of the D channel in the digital subscriber line of the large-scale information communication network and test the normality of the digital telephone (including other terminals) and the line. You can Also, the status of the digital subscriber line can be monitored when needed.

[Brief description of drawings]

FIG. 1 (a) is a basic configuration diagram of the present invention, FIG. 1 (b) is a bit accommodation diagram of a specific channel for testing, FIG. 2 is a configuration diagram of an embodiment of the present invention, and FIG. 3 is a conventional system. It is a block diagram. In Fig. 1 (a), 10: Extraction circuit 11: Insertion circuit 12: Test pull-in circuit 20: Line time switch LTSW 21: Maintenance device 13,17,18: Extraction circuit 14,16, 19: Insertion circuit 15: Multiplexing circuit

Front Page Continuation (72) Inventor Kiyofumi Mise 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa, Fujitsu Limited (72) Inventor Takashi Nara 1015, Kamedota, Nakahara-ku, Kawasaki, Kanagawa Prefecture, Fujitsu Limited (56) Reference Document JP-A-57-136850 (JP, A)

Claims (1)

[Claims] 1. A D channel extracting / inserting circuit in a digital switching system having a subscriber line for transmitting communication information between a digital terminal and a digital concentrator circuit on a B channel and transmitting control information on a D channel, Each of the input side highway (100) and the output side highway (110) of the digital concentrator circuit is provided with an extraction circuit (10) and an insertion circuit (11) for D channel data, and a test lead-in circuit (12) is provided for the highway. The D channel data that is provided between the extraction circuit (10), the insertion circuit (11) and the digital subscriber line circuit controller (DLCC) and is input to and output from the test lead-in circuit (12) is the test lead-in in the subscriber line. Connected to the B channel of the specific channel for the maintenance device (21) via the digital concentrator circuit. A D channel extraction / insertion circuit characterized in that the D channel data is transmitted / received between the maintenance device and the subscriber line by connecting to the.