JPH06197119A - Asynchronous transfer mode subscriber's circuit for analog line - Google Patents

Abstract

PURPOSE:To connect an existing network with an ATM network by making a signal from an analog subscriber's line to an ATM. CONSTITUTION:The transfer of PCM information between an analog subscriber's circuit 2 and an ATM cell multiplex circuit 9 is performed by making the signal to the ATM cell by an ALL type 1 processing part 14 and an ATM cell multiplex branching part 8, and the transfer of a level signal between the analog subscriber's circuit 2 and the ATE cell multiplex circuit 9 is performed by making the signal to a message by a message converting circuit 5, and converting it into the ATM cell by a layer 2 processing part 6, AAL type 3 and 4 processing part 7, and ATM cell multiplex branching part 8. Moreover, at the time of receiving the message of tone designation and PB signal receiving instruction from the layer 2 processing part 6, the tone transmission and the PB signal reception are operated by controlling a switch 10, PB signal receiving circuit 11, and tone transmitting circuit 12 by the message converting circuit 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used in an asynchronous transfer mode switch which accommodates analog subscriber lines. It is used for an asynchronous transfer mode switch that accommodates analog subscriber lines by providing a cellizing function and converting the subscriber lines into asynchronous transfer mode. The conventional subscriber exchange is used as an upgraded asynchronous transfer mode exchange.

[0002]

2. Description of the Related Art In asynchronous transfer mode (ATM), all information is transferred in fixed-length packets called cells.
As a method of exchanging, various methods such as various speeds and various media can be efficiently realized at high speed as ISD.
N (Integrated Services Dig)
It is a basic technology for building an ital network. Such an ATM B-ISDN (Bro
existing ISDN) when constructing an existing S
TM (Synchronous Transfer M)
It is necessary to have a function of interconnecting with an ode) or connecting an existing terminal of the STM system or an existing subscriber line directly to the ATM network. In particular, it is an indispensable function in the process of efficiently accommodating the existing network in the integrated network by ATM.

As a method of converting an existing network into an ATM, an inter-network adapter is used to connect the existing network and an ATM network, or ST
A method to make ATM from the trunk line by adding a cell assembling / disassembling function to the trunk outgoing line of the M switch, or a subscriber line by deploying the cellizing function for multiple outgoing lines of the subscriber switch or subscriber line To ATM from the terminal, or by arranging an ATM adapter on the terminal side and directly connecting the existing terminal to the ATM.
It is possible to consider a method of making it possible to accommodate it in the net.

[0004]

However, in the prior art, the methods are roughly classified into the above-mentioned rough methods, and the respective realization methods have not been established yet.

The present invention has been made under such a background, and it is possible to connect an existing network to an ATM network by converting an analog subscriber line into ATM, and to replace the conventional subscriber exchange with an ATM exchange. In this case, it is an object of the present invention to provide an asynchronous transfer mode subscriber circuit for an analog line in which an existing analog subscriber line can be accommodated in an ATM switch efficiently and economically with the same interface as the conventional one.

[0006]

SUMMARY OF THE INVENTION The present invention is an asynchronous transfer mode subscriber circuit for an analog line comprising an analog subscriber circuit (2) accommodating an analog subscriber line, the level signal from said analog subscriber circuit. To a message according to a specified format, and layer 2 processing including a D channel link access procedure is performed on the output of this conversion means, and type 3 and type of asynchronous transfer mode adaptation layer processing First processing means (6, 7) for forming cells by 4 processing
And second processing means (14) for converting the pulse code modulation information from the analog subscriber circuit (2) into cells by the type 1 processing of the asynchronous transfer mode adaptation layer processing,
The first processing means (6, 6), comprising multiple branching means (8) that multiplexes and decomposes signals between the first processing means and the second processing means and the interface line and transmits and receives them in the form of asynchronous transfer mode cells. 7) includes means for decomposing the output of the multi-branching means into a message and giving it to the converting means (5), and the second processing means (14) decomposing the output of the multi-branching means into pulse code information. The converting means (5) includes means for giving to the analog subscriber circuit (2), and based on the message from the first processing means, the converting means (5) converts the level signal into a level signal to convert the analog subscriber circuit. In the case of one of the tone designation and the push button signal reception instruction, a means for outputting one of them and a selection signal is included.

The present invention also includes a receiving circuit (11) for receiving a push button signal in response to the push button signal reception instruction, a transmission circuit (12) for transmitting a tone designated by the tone designation, and the selection signal. A switch (10) for selecting and connecting the analog subscriber circuit to one of the receiving circuit, the transmitting circuit and the second processing means, and the analog subscriber circuit and the third processing means. An echo canceller (13) inserted between them, the conversion means (5) may include means for converting the output of the receiving circuit into a message and giving it to the first processing means.

[0008]

[Function] ATM cells are converted to ATM cells for PCM information
When sending and receiving with the exchange main body, converting the level signal into a message, converting it into ATM cells and transmitting and receiving with the ATM exchange main body, and when the message from the ATM exchange main body is a tone designation signal Sends the specified tone to the analog subscriber circuit, and in the case of the push button signal reception instruction signal, receives the push button signal from the analog subscriber circuit and converts it into a message.
By converting the M cells and transmitting them to the ATM switch, the subscriber line can be converted to ATM and the existing network can be connected to the ATM network. When the conventional subscriber switch is replaced with the ATM switch, the existing analog subscriber line is used. With the completely same interface as before, it can be accommodated efficiently and economically in an ATM exchange.

To accommodate the STM line in the ATM network, C
The function of assembling and disassembling into ATM cells, that is, the ATM adaptation layer processing (ALL processing) defined by CITT (International Telegraph and Telephone Consultative Committee) is essential. A method of performing where and how to perform this ALL processing is conceivable. One of the methods is to use an STM line on a conventional ATM.
It can be considered that the function is accommodated by an exchange and the ALL function is provided at the entrance / exit to the multiple trunk line. Although this method is relatively easy to introduce, it cannot be said to be an ATM integrated network because an ATM switch will remain in the future even if ATM is advanced.

Since local calls are not converted to ATM,
The advantages of using ATM for local calls cannot be used. In view of this, the present invention performs the ALL processing for each subscriber line in the subscriber exchange, thereby
This is a method that enables TM conversion. In order to accommodate analog subscriber lines, the subscriber circuits, or BORs, must be provided for each line.
The SCHT circuit is required, and it is an idea of the present invention to add an ALL function to the BORSCHT function.
LSI with ALL function integrated with BORSCHT function
(Large Scale Integrated C
If it becomes an ircuit, there is a possibility that it will be possible to achieve sufficient economic efficiency in the future.

Here, when accommodating an analog subscriber line in an ATM network, not only the user information is converted into ATM cells, but also the signaling system by the analog subscriber line is A.
It must be processed by the TM switch. The types of the signals are in-channel PCs such as PB signals and tone signals.
There are M signal and level signal like on-hook detection,
The former particularly requires a signal processing circuit such as a PB signal receiving circuit (PBR). A method often used in conventional exchanges is a method in which a PB receiving circuit or the like is installed so as to be commonly used as a trunk and connected by a time switch whenever necessary. If this method is applied as it is, AT
A time switch is required in addition to the M switch, and the interface between the subscriber line corresponding unit and the main body has both ATM and STM, resulting in a complicated switch configuration.
Also, a line for interfacing the level signal is required.

One method therefor is to convert not only user information but also signals into cells of type 1 in the subscriber line corresponding part, and further add an ALL processing function to a signal device trunk such as a PB receiving circuit to make all of them. This is a method of unifying with an ATM cell interface. This method does not require the STM switching function.
The complexity of the configuration resulting from having both M and STM switches can be avoided. However, from the viewpoint of adding a function for accommodating an existing analog subscriber line to the ATM switch, not only the subscriber line corresponding part but also the switch itself has an analog subscriber line signaling system such as a PB receiving circuit. It is necessary to add a unique device. Therefore, in the present invention, a signal circuit such as a PB receiving circuit is also installed corresponding to the line, and the reception result and the detection result of the physical change due to the level signal are edited as a message, and the message is
We devised a method to make a TM cell and interface with the main body of the exchange. As a result, the signal processing peculiar to the analog subscriber line signaling system is terminated at the subscriber line corresponding part and all signals are transmitted and received in the form of a message, so that it can be realized without adding special hardware to the exchange main body. That is, the layer 2 and layer 1 for transmitting and receiving the message are ATM
If it is shared with the signaling device of the subscriber line, only the software for performing layer 3 needs to be added. ATM in this way
The existing analog subscriber line can be accommodated in the ATM network only by replacing the line corresponding part of the exchange with the line corresponding part accommodating the analog subscriber line.

[0013]

Embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, an asynchronous transfer mode subscriber circuit for an analog line includes an analog subscriber circuit 2 that accommodates an analog subscriber line 1.

Here, the feature of the present invention is that the message converting circuit 5 and the output of the message converting circuit 5 are used as converting means for converting the level signal from the analog subscriber circuit 1 into a message in accordance with a specified format. Link access procedure for D channel (LAPD, L
ink Access Procedure onth
e D-channel) including Layer 2 processing,
Asynchronous transfer mode Adaptation layer processing (ALL
Layer 2 processing section 6 and ALL type 3, 4 processing section 7 as the first processing means for converting cells into cells by the type 3 and type 4 processing, and pulse code modulation information (PCM information) from the analog subscriber circuit 2. Type 1 of ALL processing
Second processing means (14) for making cells by processing, layer 2 processing unit 6, ALL type 3, 4 processing unit 7 and ALL
An ATM cell multiplex branching unit 8 is provided as a multiplex branching unit that multiplexes and decomposes a signal between the type 1 processing unit 14 and an ATM cell multiplex line 9 as an interface line and transmits / receives it in the form of an asynchronous transfer mode cell (ATM cell). The layer 2 processing unit 6 and the ALL type 3 and 4 processing units 7 include means for decomposing the output of the ATM cell multiplex / branching unit 8 into a message and giving it to the message conversion circuit 5, and the ALL type 1 processing unit 14
Includes means for decomposing the output of the ATM cell multiplex / branching unit 8 into PCM information and giving it to the analog subscriber circuit 2. The message converting circuit 5 is based on the message from the layer 2 processing unit 6 and in the case of a level signal. It is characterized in that it includes means for converting the level signal and giving it to the analog subscriber circuit 2 and outputting one of the tone designation and push button signal reception instruction and the selection signal.

Further, a PB signal receiving circuit 11 as a receiving circuit for receiving a push button signal (PB signal) in response to the push button signal reception instruction, and a tone transmitting circuit 12 as a transmitting circuit for transmitting a tone designated by the tone designation. A switch 10 for selecting and connecting the analog subscriber circuit 2 to one of the PB signal receiving circuit 11, the tone transmitting circuit 12 and the ALL type 1 processing section 14 by the selection signal, and the analog subscriber circuit 2. Echo canceller 1 inserted between the ALL type 1 processing unit 14
3, the message conversion circuit 5 includes means for converting the output of the PB signal reception circuit 11 into a message and giving it to the layer 2 processing section 6.

The operation of the asynchronous transfer mode subscriber circuit for an analog line having such a configuration will be described. FIG. 2 is a diagram showing the structure and encoding of a division / assembly sublayer protocol data unit handled by the type 1, type 3 and type 4 protocols of the asynchronous transfer mode adaptation layer of the asynchronous transfer mode subscriber circuit for an analog line of the present invention. is there. 2A shows the type 1 of ALL processing, FIG. 2B shows the type 3 of ALL processing, and FIG.
(C) shows type 4 of ALL processing. Furthermore, SN is a sequence number, SNP is a sequence number protection, and SAR.
-PDU is a subassembly protocol data unit for division and assembly,
ST is a segment type, Res. Is a reserved field, LI is a length indicator, CRC is a redundancy check code and M
ID indicates a multiplexing identifier.

In FIG. 1, the analog subscriber circuit is SL.
IC (Subscriber Line Interface)
ACE Circuit) is an existing subscriber circuit, which has a BORSCHT function such as power feeding, two-wire / four-wire conversion, analog-digital conversion, etc., and performs analog-digital conversion and μlaw or Alaw PCM pulse code modulation is coded and output to the PCM signal input / output line 3, and the PCM signal is converted from the PCM signal input / output line 3 into an analog signal such as voice by analog / digital conversion, and is then transmitted to the analog subscriber line 1. Output.

Further, the analog subscriber circuit 2 performs off-hook monitoring of the subscriber, that is, makes a call detection, and when detected, outputs it to the level signal input / output line 4 as a level signal change. The message converting circuit 5 converts the level signal change into a message having a specified format. For example, a message indicating that off-hook is detected is created, the layer 2 processing unit 6 converts the message into an LAPD frame, and the ALL type 3 and 4 processing units 7 receive the LA
The message is divided into cell length units as shown in FIGS. 2B and 2C in which PD frames are formed. The ATM cell multiplex / branching unit 8 sends the outputs of the ALL type 3 and 4 processing units 7 in the form of cells to the main body of the ATM switch through the ATM cell multiplex line 9.

Further, for example, when a dial tone transmission instruction and a PB reception instruction message are input in the form of cells from the ATM switch via the ATM cell multiplex line 9, the message conversion circuit 5 determines the respective contents based on the contents of the message. An instruction is given to the tone transmission circuit 12 or the PB reception circuit 11, and a selection signal is given to the switch 10. On the basis of this selection signal, the switch 10 is connected to the PB signal receiving circuit 11 at the output side from the analog subscriber circuit 2 and connected to the tone transmitting circuit 12 at the input side to the analog subscriber circuit 2 in the PCM signal input / output line 3. . A dial tone is designated as a tone in the tone transmission circuit 12.

As described above, the analog subscriber circuit 2
If a dial tone is sent to the subscriber terminal via the, and the subscriber hears it and sends a PB signal, the PB signal receiving circuit 11 receives the PB signal and the message conversion circuit 5 receives the reception result. Is converted into a message and sent to the main body of the ATM exchange by ATM cells.

When a call is established after the call control processing, the switch 10 connects the PCM signal input / output line 3 to the echo canceller 13. The AAL type 1 processing section 14 converts the PCM signal (information such as voice) from the analog subscriber circuit 2 into cells at a fixed speed by the type 1 processing of ALL processing as shown in FIG. 8 is ALL
An ATM header is added to the output of the type 1 processing unit 14
It is sent to the TM cell multiplex line 9. Further, the ATM cell multiplex branching unit 8 and the ALL type 1 processing unit 14 decompose the PCM signal from the ATM cell multiplex line 9 and give it to the analog subscriber circuit 2 via the echo canceller 13 and the switch 10 to the subscriber terminal. Communicate information. The echo canceller 13 cancels the echo generated at the time of the two-wire / four-wire conversion in the analog subscriber circuit 2 as necessary.

[0023]

As described above, according to the present invention, the ATM
In constructing the network, the analog subscriber line, which is presently a huge amount of equipment, can be accommodated as it is in the ATM network, and there is an excellent effect that it can contribute to the rapid and economical advancement of ATM conversion. In addition, LSI (Large Scale)
If the economy and downsizing can be realized by the integrated circuit, etc., existing services such as a telephone can be provided more economically.

[Brief description of drawings]

FIG. 1 is a block diagram of an asynchronous transfer mode subscriber circuit for an analog line according to an embodiment of the present invention.

FIG. 2 is a diagram showing the structure and encoding of a divided and assembled sublayer protocol data unit handled by the type 1, type 3 and type 4 protocols of the asynchronous transfer mode adaptation layer of the asynchronous transfer mode subscriber circuit for analog lines of the present invention. .

[Explanation of symbols]

1 analog subscriber line 2 analog subscriber circuit 3 PCM signal input / output line 4 level signal input / output line 5 message conversion circuit 6 layer 2 processing unit 7 ALL type 3, 4 processing unit 8 ATM cell multiplexing / branching unit 9 ATM cell multiplex line 10 switch 11 PB signal receiving circuit 12 tone transmitting circuit 13 echo canceller 14 ALL type 1 processing unit CRC redundancy check code LI length display MID multiplex identifier SAR-PDU division assembly sublayer protocol data unit SN sequence number SNP sequence number protection Res. Reserve field

Claims (2)

[Claims] 1. An asynchronous transfer mode subscriber circuit for an analog line, comprising an analog subscriber circuit (2) for accommodating an analog subscriber line, wherein a level signal from the analog subscriber circuit is converted into a message according to a specified format. A conversion means (5) for converting and layer 2 processing including a D channel link access procedure for the output of this conversion means, and cell conversion by type 3 and type 4 processing of the asynchronous transfer mode adaptation layer processing Processing means (6, 7)
And second processing means (14) for converting the pulse code modulation information from the analog subscriber circuit (2) into cells by the type 1 processing of the asynchronous transfer mode adaptation layer processing,
The first processing means (6, 6), and multiple branching means (8) for demultiplexing the signals between the first processing means and the second processing means and the interface line and transmitting and receiving in the form of asynchronous transfer mode cells. 7) includes means for decomposing the output of the multi-branching means into a message and giving it to the converting means (5), and the second processing means (14) decomposing the output of the multi-branching means into pulse code information. The converting means (5) includes means for supplying to the analog subscriber circuit (2), and based on the message from the first processing means, the converting means (5) converts into a level signal in the case of a level signal, and then the analog subscriber circuit. Asynchronous transfer mode subscription for analog lines, characterized in that it includes means for outputting one of the tone designation and push button signal reception instruction in the case of one of them and a selection signal. Circuit. 2. A receiving circuit (11) for receiving a push button signal in response to the push button signal reception instruction, a transmission circuit (12) for transmitting a tone designated by the tone designation, and the analog subscription by the selection signal. A switch (10) for selectively connecting an operator circuit to one of the receiving circuit, the transmitting circuit and the second processing means.
And an echo canceller (13) inserted between the analog subscriber circuit and the third processing means, wherein the converting means (5) converts the output of the receiving circuit into a message and outputs the message. An asynchronous transfer mode subscriber circuit for an analog line as claimed in claim 1, including means for providing to the processing means.