JPS63187857A - Digital exchange network - Google Patents

Abstract

PURPOSE:To obtain an economical exchange network by providing an analog trunk as an interface to a metallic relay line and a PCM terminal equipment to one digital exchange and utilizing them by plural exchanges. CONSTITUTION:When the connection from an exchange 1 to the metallic relay line 6 is desired, the exchange 1 uses an MF signal transmitter-receiver and a supervisory signal transmitter-receiver in relay line signal equipments 15, 25 to transmit/receive a required control signal with an exchange 2, the exchange 2 uses an analog trunk 27 and a PCM terminal equipment 26 to convert the transmitted/received control signal as the control signal for the metallic relay line 6 and sends the result to the metallic relay line 6. The exchange 1 is connected to the metallic relay line 6 while using the exchange 2 as the relay exchange and when a holding signal is sent from an attendant board via the metallic relay line 6, the exchange 2 uses the analog trunk 27 and the PCM terminal equipment 26 to convert the terminated holding signal into a digital control signal defined separately and relays it to the exchange 1.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a digital switching network, and more specifically, a digital switching system including an analog trunk as an interface to a metallic trunk line and a PCM terminal equipment. When a first exchange and a second exchange not including the first exchange are installed, and it is desired to connect the second exchange to the metallic trunk line, the second exchange connects the first exchange to the first exchange. The present invention relates to a digital switching network connected to the metallic trunk line as a trunk exchange.

[Conventional technology]

In recent years, digitalization of transmission lines in telephone exchange networks has been progressing, but some analog metallic lines using the conventional loop signaling system still remain as transmission lines. Therefore, when developing a new digital exchange, it is necessary to provide the new exchange with interface functions necessary for connection with existing old analog equipment.

Examples of recent digital switching equipment include the Research and Practical Application Report VOL published by Nippon Telegraph and Telephone Corporation/Telecommunications Research Institute,
33 No. 7 An example may be given of the digital exchange described in 1984.

FIG. 3 is a block diagram showing an outline of the configuration of such a conventional digital exchange.

In the same figure, 1 and 2 are digital exchanges, and 3
is a telephone, 4 is a reception desk (110 or 1 for police, fire department, etc.)
19 is a reception desk), 5 is a subscriber line, 6 is a metallic trunk line, 7 is a digital line, 11.21 is a processing device, respectively, 12°22 is a distribution stage channel device,
13.23 is a line concentrator, 14.24 is a subscriber line signal device, 15.25 is a trunk line signal device, 16.26 is a PCM terminal device, 17゜27
are each analog trunks.

Among the metallic relay lines currently accommodated in digital exchanges, the number of general relay lines using LMOGT, LMICT, etc. is expected to gradually decrease as the digitalization of transmission lines progresses. Although the number of metallic relay lines facing the fire station and the metallic relay line facing the outskirts station is small, it is thought that they will remain for a certain period of time. Such a special reception desk is shown as 4 in FIG.

In addition, police/fire department lines and long-distance telephone lines require a hold re-signaling function so that the caller can re-call the caller if the caller dials first, and a special signaling system has been established for this purpose.

Now, in FIG. 3, when a telephone 3 housed in a digital exchange 1 makes a call, if the other party is a general telephone subscriber, the line is connected to a concentrator 13, a distribution channel device 12, and a digital line 7. The call is then extended to another digital exchange 8!2 according to the standard digital interface method and is connected to the other party's subscriber. However, if the other party making the call is a reception desk 4 such as the police or fire department, the reception desk 4
The trunk line 6 connected to is a metallic line based on old analog technology that has been used in the past, so a PCM specially provided as an interface for this purpose is used.
After converting the signal format via a terminal device (mainly performing A/D conversion) 16 and an analog trunk 17, the signal is connected to the metallic trunk line 6.

[Problem that the invention seeks to solve]

As long as the metallic trunk line 6 remains, due to these technical circumstances, each digital exchange must be equipped with a PCM terminal equipment 16 and an analog trunk 17 as an interface to the metallic trunk line, which poses a problem. That's why.

In other words, in order to support a small number of special lines, such as the Metalli/ν relay line 6, PCM terminal equipment and analog trunks were required for each exchange, making the conventional switching network an uneconomical system. I can do it. In addition, when developing a new switch, if the control interface of the processing device in the switch is changed, it becomes necessary to develop a new analog trunk as described above, which poses the problem of high development costs.

Furthermore, if different exchanges (for example, a crossbar exchange and a digital exchange) are installed in the same station, an additional trunk is installed to bring in the police and fire lines from each exchange, consolidate them, and connect them to the gold side. Therefore, there was a problem in that the number of trunk codes to be developed increased.

An object of the present invention is to provide one digital exchange consisting of PCM
As long as the terminal equipment and analog trunks are installed, other digital exchanges do not need to be equipped with these, but other digital exchanges can be used as metallic relays by using the digital switching equipment that is equipped with the PCM terminal equipment and analog trunks as a relay exchange. The object of the present invention is to provide a digital switching network which solves the above-mentioned problems by making it possible to connect to a line.

[Means for solving problems]

In order to solve the problem, in the present invention, the digital exchange includes an analog trunk and a PCM terminal equipment as an interface to the metallic trunk line, and a trunk line equipped with an MF (multifrequency) signal transmitter/receiver and a supervisory signal transmitter/receiver. It does not include the first exchange including the signaling equipment, the analog trunk as an interface to the metallic trunk line, and the PCM terminal equipment, but does include the trunk line signaling equipment equipped with the MF signal transceiver and the supervisory signal transceiver. A second exchange was installed in the digital switching network.

[Effect]

When a connection from the second exchange to the metallic trunk line is desired, the second exchange uses the MF signal transmitter/receiver and the supervisory signal transmitter/receiver, which is standard among digital exchanges. The first exchange transmits and receives the necessary control signals to and from the first exchange according to the digital interface system, and the first exchange transmits and receives the control signals to and from the second exchange through the analog trunk and the PCM. The terminal equipment converts it into a control signal for the metallic trunk line, sends it to the metallic trunk line, and sends it to the second metallic trunk line.
The exchange is connected to the metallic trunk line using the first exchange as a relay exchange, and when a hold re-signal is sent from the reception desk connected to the end of the metallic trunk line via the metallic trunk line, the first exchange is connected to the metallic trunk line. At the exchange,
The hold re-signal terminated by the analog trunk and PCM terminal equipment is converted into a separately defined digital control signal, and then relayed to the first exchange.

With conventional technology, each exchange has analog trunks and PCM
Unlike the conventional technology, which requires terminal equipment, the present invention is different from the prior art in that these devices are installed in only one exchange, and the functions thereof can be shared by multiple exchanges.

Note that the analog trunk, which is an interface device for the loop signal system, and the PCM terminal device that performs A/D conversion, exchange between 2 wires and 4 wires, etc. may be integrated.

〔Example〕 The present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In this figure, the same parts as in FIG. 3 are given the same reference numerals.

In comparison with FIG. 3, it will be appreciated that in FIG. 1, the digital exchange 1 does not include PCM terminal equipment and analog trunks.

FIG. 2 is a control sequence diagram showing an example of the operation of the embodiment shown in FIG.

The circuit operation related to the present invention will be explained below with reference to FIGS. 1 and 2.

When a subscriber (telephone 3) of the exchange 1 makes a call, the line concentrator 13 detects this and reports it to the processing device 11. Then, the processing device 11 sends the subscriber line signal device 14 to the DT (
dial tone) is sent to the telephone set 3. When this DT is heard, the telephone 3 sends (dials) the selected digits. At this time, when the selected number is “110”, the police command center is “110”.
If it is "119", it is necessary to connect to the fire control console, and if it is "100", it is necessary to connect to the relay station, and now it is assumed that one of these selected numbers has been sent and it is necessary to connect to reception desk 4. .

If the reception desk 4 is of a different type, the connection between the reception desk 4 and the exchange is made using a different special signal system, and different analog trunks are prepared depending on the signal system. However, here, we will explain the specific differences between each signal system (both lines, A line disconnection, B line station, etc.)
Since this is not a problem, the following operations will be explained simply using function names such as activation signal, response signal, disconnection signal, hold re-signal, and call-end signal.

The selected digits sent by the subscriber (telephone 3) are eventually received in the subscriber line signaling device 14 by a PBR (PB signal receiver) if it is in the form of a PB (button button) signal, or by a DP (dial pulse) signal. If the format is DP
Received by R (DP signal receiver). In FIG. 1, the subscriber line signaling device 14 is of the type following the distribution stage channel device 12, but it may be of the type preceding the distribution stage channel device 12.

The processing device 11 translates the received digits received by the subscriber line signaling device 14 and performs outgoing connection processing using the trunk line signaling device (TSE) 15. This outgoing connection process is performed by general MF.
The process is exactly the same as in the case of an individual signaling relay line using (multi-frequency) signals, and as shown in Figure 2, the activation signal - MFR capture signal - KP double signal KP signal confirmation signal - M
Trunk line signal device 15 of exchange 1 and exchange 2 in order of F-failure signal
It is transmitted and received between the trunk line signal device 25 and the trunk line signal device 25.

Here, SSS refers to a supervisory signal transmitter, and the supervisory signal transmitter SS provided in the trunk line signaling device 15
The activation signal is transmitted by S toggling its supervisory signal bits from 1 to 0 together. The supervisory signal receiver SSR provided in the trunk line signal device 25 on the exchange 2 side receives this signal.

Next, the supervisory signal transmitter SSS provided in the trunk line signaling device 25 on the exchange 2 side changes the supervisory signal bit from 1 to O, thereby sending an MFR (multifrequency receiver) capture completion signal. , which is received by the supervisory signal receiver SSR provided in the trunk line signaling device 15 on the exchange 1 side.

Therefore, this time, the M
The MF flaw signal is transmitted from the F signal transmitter MFS, but before that, the KP double signal indicating that the MF flaw signal will be sent from the MF signal transmitter MFS of the trunk line signal device 15 to the trunk line signal device. 25 MF signal receiver MFR
send to

Then, the supervisory signal transmitter SSS of the trunk line signaling device 25,
By changing the supervisory signal bit from 0 to 1, a KP signal confirmation signal is sent, which is received by the supervisory signal receiver SSR of the trunk line signaling device 15. After that, the MF signal transmitter MFS of the trunk line signal device 15 sends out "IXY" from the MF flaw signal, which is transmitted to the trunk line signal device 2.
The MF signal receiver MFR of No. 5 receives the signal.

Then, the middle line signaling device 25 sends an RBT (ringback tone) to the subscriber (telephone 3), and the processing device 2
1 sends an activation signal to the reception desk 4 via the analog trunk 27.

In order to eliminate call loss during relay, a dedicated time slot may be allocated on the digital line between exchange 1 and exchange 2.

In the exchange 2, when the incoming connection process is completed, the corresponding analog trunk 27 is activated as described above and connected to the reception console 4, as in the case of a call originating from a subscriber accommodated in the exchange 2, and the reception console 4 Outputs a response signal. As a result, the accommodated subscriber (telephone 3) of exchange 1 is connected to analog trunk 27, R of exchange 2.
It is possible to communicate with the reception console 4 via the OM terminal device 26.

Here, when the caller makes a first call, the reception console 4 sends a hold re-call signal when the caller calls again from the reception desk 4. When the analog trunk 27 detects a hold re-signal, the processing device 21 converts it into a pulse having a timing width of a certain time and sends it to the exchange 1. When the exchange 1 detects this timing pulse, it calls the subscriber (telephone 3).

By converting the hold re-signal (loop signal) into a timing pulse and relaying it as described above, the subscriber accommodated in the exchange 1 can be re-called.

Call termination processing is the same as for general lines. Although the embodiment has been explained using an analog telephone, the subscriber can similarly realize the present invention using either an analog telephone or a digital telephone.

〔Effect of the invention〕

As explained above, according to the present invention, an analog trunk and a PCM 4-station device are installed in one digital exchange, and this can be used by multiple exchanges, so there is an advantage that an economical switching network can be provided. be.

Furthermore, when developing a new switch, there is no need to develop special equipment to support existing interface functions (this makes it possible to reduce development costs and shorten the development period).

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a control sequence diagram showing an example of the operation of the embodiment shown in FIG. 1, and FIG. 3 is a block diagram showing a conventional digital exchange.
It is. Explanation of symbols 1. 2...Digital exchange, 3...Telephone, 4...
. . . Reception desk, 5. Subscriber line, 6. Metallic trunk line, 7. Digital trunk line, 11.21. Processing device, 12.22. Distribution stage channel device, 13.2
3... Line concentrator, 14.24... Subscriber line signaling device, 15°25... Trunk line signaling device, 16.26...
PCM terminal equipment, 17.27...Analog trunk.

Claims (1)

[Claims] 1) As a digital exchange, an analog trunk and P as an interface to a metallic trunk line.
A first exchange that includes a CM terminal station device and a trunk line signaling device equipped with an MF (multifrequency) signal transmitter/receiver and a supervisory signal transmitter/receiver, an analog trunk as an interface to the metallic trunk line, and a PCM terminal station device. However, a trunk line signaling device equipped with an MF signal transmitter/receiver and a supervisory signal transmitter/receiver is equipped with a second exchange including the same, and connection from the second exchange to the metallic trunk line is desired. When the second exchange uses the MF signal transmitter/receiver and the supervisory signal transmitter/receiver, the second exchange transmits and receives the necessary control signals to that effect in accordance with the digital interface method that is standard between digital exchanges. At the same time, the first exchange converts the control signal exchanged with the second exchange into a control signal for the metallic trunk line using the analog trunk and PCM terminal equipment. A second exchange is connected to the metallic trunk line using the first exchange as a trunk exchange, and a hold re-signal is sent from a reception desk connected to the end of the metallic trunk line via the metallic trunk line. when the first exchange converts the hold re-signal terminated by the analog trunk and PCM terminal equipment into a separately defined digital control signal, and then relays this to the second exchange. A distinctive digital exchange network.