JP2000031996A - Atm exchange - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ATM exchange by which voice communication is attained even between asynchronous transfer mode ATM terminals of different ATM adaptation layer AAL type. SOLUTION: The ATM exchange is provided with an identification means 11 that identifies that an AAL type of an ATM cell of voice data from a caller differs from an AAL type of an ATM cell of voice data to a called party in the case that communication data are the voice data in a forming state of a communication channel and with a voice type conversion means 13 that converts an AAL type of the ATM cell of the voice data. A control means 11 intervenes the voice type conversion means 13 in the communication channel to convert the AAL type of the ATM cell when the identification means 11 identifies that the AAL type of the ATM cell of the voice data from the caller differs from the AAL type of the ATM cell of the voice data to the called party.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ATM switching device suitable for use as, for example, a main device of a key telephone system.

[0002]

2. Description of the Related Art A switching system required for a next-generation network is to respond to an increase in information transmission speed.
An ATM (Asynchronous Transfer Mode) exchange method has been provided to satisfy the above requirements, for example, having a variable transmission rate function and capable of transmitting multimedia information.

In this ATM system, information sent from a transmitting side to a receiving side is divided into 48 bytes, a 5-byte header is added thereto, and high-speed transmission is performed in units called fixed-length cells of 53 bytes. . The header contains information for call identification and information for forming a communication path to the destination. Based on the information in the header, cells are exchanged at high speed by an ATM switch having a hardware configuration. You.

[0004] On the receiving side, the information of the header of the received cell is confirmed, the data in units of cells are concatenated, and the original information is assembled.

FIG. 22 shows the structure of this cell.
This is the case of UNI (User Network Interface). That is, the cell is composed of a header portion HD of 5 bytes (octets in FIG. 22 are equal to bytes) and a data portion DT of 48 bytes. The header part HD is a GFC (Generic Fl
ow Control; general flow control), VPI (VirtualPat
h Identifier; virtual path identifier (VCI), Virtual C
hannel Identifier (virtual channel identifier), PT (P
ayload Type: payload type (indicating the type of user information of 48 bytes), CLP (Cell Loss Prio)
rity; cell loss priority display), HEC (Header Error Con
trol; a header error correction code).

The VPI and VCI are ATM routing fields, that is, fields for determining what communication path a cell selects. UNI (User
Network Interface), 1 byte for VPI, VC
Two bytes are allocated to I. VCI is a virtual channel number for call identification, and VPI is an identifier for specifying a communication path.

In the ATM switching network, the VPI and VCI are allocated and set between the originating terminal, the originating exchange, the transit exchange, the destination exchange, and the destination terminal, thereby forming a virtual path. Communication is performed.

[0008] The ATM standard protocol has a hierarchical structure, and is unified with ATM cells.
AAL (ATM adaptation layer) for matching / adjusting 8-byte user information with data units of various higher-level applications such as voice and data, and adding a 5-byte ATM cell header to 48-byte user information An ATM layer that processes ATM cells, and an SDH (Synchronous Digital Hierar
chy) and a physical layer for generating a frame.

The AAL defines several types of protocols for realizing various services. Of these, voice information is generally transmitted and received by AAL type 1 ATM cells handling fixed transmission rate traffic. AAL type 5 is used for data communication such as control data.

[0010]

For this reason, an ATM terminal connected to an ATM switching device for exchanging voice information using ATM cells is an AA for voice information.
L type 1 cell assembly / disassembly unit (hereinafter referred to as CLAD (Cell
Assembly and Disassembly) and AAL type 5 CLAD for call control and data communication.
There is a problem that the LAD must be provided and the ATM terminal becomes expensive.

Therefore, a mechanism for communicating voice information with AAL type 5 has been standardized by the ATM Forum. However, when voice communication is attempted between an AAL type 5 ATM terminal conforming to this standard and an AAL type 1 ATM terminal, communication cannot be performed because the AAL type is different.

That is, as shown in FIG.
When a call is made from an AL type 5 ATM terminal,
A setup message containing the AL type information is transmitted to the AAL type 1 ATM terminal via the exchange. Since the AAL type 1 ATM terminal has a different AAL type, it sends a release request to the exchange.
For this reason, the exchange sends a release message to the AAL type 5 ATM terminal, and it is released, so that voice communication cannot be performed.

When transmitting voice data using AAL type 5 ATM cells, the voice data is transmitted over IP (Integer).
rnet Protocol) The packet may be transmitted as a packet or may be transmitted after being further compressed. The ATM terminal which handles the ATM cells with packetization and compression for voice data and the AAL type 5 without packetization and compression are used. Communication cannot be performed with an ATM terminal that performs communication of the voice ATM cell. SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide an ATM switching device that enables voice communication even between ATM terminals of different AAL types. It is another object of the present invention to provide an ATM switching apparatus capable of performing voice communication even between ATM terminals having the same AAL type but different voice data processing.

[0014]

In order to solve the above-mentioned problems, an ATM switching apparatus according to the first aspect of the present invention is configured such that when a communication path is formed, communication data is voice data, and voice data from a calling side is transmitted. Identification means for identifying that the AAL type of the ATM cell is different from the AAL type of the ATM cell of the voice data to the called side; voice type conversion means for converting the AAL type of the ATM cell of the voice data;
The identification means has identified that the communication data is voice data, and the AAL type of the ATM cell of the voice data from the calling side is different from the AAL type of the ATM cell of the voice data to the called side. Sometimes, the voice type conversion means is interposed in the communication path to
And control means for performing type conversion.

The ATM switching apparatus according to the invention of claim 11 is a terminal interface unit to which an ATM terminal is connected, and processes according to a control instruction into voice data obtained by decomposing an AAL type 5 voice ATM cell. A voice type conversion unit for converting the processed voice data into ATM cells of AAL type 5, a control unit for controlling the entire system including the terminal interface unit and the voice type conversion unit, An ATM switching device comprising: a unit; an ATM switch for interconnecting the terminal interface unit and the voice type conversion control unit;
The control unit, when there is a call from the ATM terminal, identification means for identifying that communication data is voice data and the ATM cell from the calling side is AAL type 5; When the identification means identifies that the communication data is voice data and that the ATM cell from the calling side is AAL type 5, the caller's AT
AT between the M terminal and the voice type conversion unit
A first communication path forming means for forming a communication path via an M switch, and a second communication path for forming a communication path via the ATM switch between the voice type conversion unit and a called party.
Communication path forming means, information related to the voice data included in the information at the time of calling to specify the destination from the ATM terminal, and voice data to be transmitted to the destination from the information of the destination. Instruction information supply means for supplying, to the audio type conversion unit, instruction information of necessary processing for audio data from the information.

[0016]

For example, as shown in FIG. 1, when a voice communication is transmitted from an AAL type 5 ATM terminal to an AAL type 1 ATM terminal, the ATM switching apparatus according to the present invention having the above-described configuration has The identification means, for example, identifies from the AAL type information included in the setup message that the ATM cell of the voice data from the calling side is AAL type 5.

Also, since the setup message includes the designation information of the other party (reception side), for example, the AT
From the AAL type information of the ATM cell of the voice data of the other party registered in advance in the M switching device, the identification means identifies the AAL type as type 1. Thus, the identification means identifies that the AAL type of the ATM cell of the voice data is different between the transmitting side and the receiving side.

Upon receiving the result of the identification by the identification means, the AT
In FIG. 1, the control means of the M exchange apparatus sets up the AAL type 1 ATM terminal, which is the communication destination, by changing the AAL type of the included ATM cell from type 5 to type 1 as shown by a broken circle. Send a message.

For this reason, the AAL type 1 ATM terminal responds to this call (CALLPROC), sends an alert message, performs connection processing, and forms a communication path with the AAL type 5 ATM terminal. Is done. When the ATM cell is transmitted from the AAL type 5 terminal to the AAL type 1 terminal by the voice type conversion control means of the ATM switching device, the AAL type 5 transmits the ATM cell to the AAL type 1 terminal.
Conversion is made to AL type 1 and, in the opposite case, from AAL type 1 to AAL type 5, and mutual voice communication is performed.

In the ATM switching apparatus according to the present invention, when the control unit identifies a voice communication call request from an AAL type 5 ATM terminal, for example, the control unit identifies the call from a setup message. A from the side
Identify the TM connection as AAL type 5. Then, based on the identification result of the identification means, the first communication path forming means forms a communication path between the calling ATM terminal and the voice type conversion unit via the ATM switch.

The second communication path forming means forms a communication path between the voice type conversion unit and the called side via the ATM switch. Further, the audio type conversion unit is provided with instruction information on necessary processing on audio data from information on audio data to be transmitted to the destination.

Thus, for example, AAL sent to the other party
When the voice data of the type 5 ATM cell needs to be converted into an IP packet or needs to be compressed,
In the voice type conversion unit, IP packetization and compression processing are performed. Conversely, voice data of an ATM cell from the other party is subjected to IP packet decomposition processing and decompression processing of compressed data, and mutual communication is performed. Will be possible.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ATM switching device according to the present invention will be described below with reference to the drawings, taking as an example the case where the ATM switching device is a main device of a key telephone system. The embodiment described below is based on the AT
This is an example in which ATM cells of voice data are exchanged as an extension call between a plurality of ATM terminals connected to an M switching device.

FIG. 2 shows an example of the configuration of the key telephone system according to this embodiment. That is, in this embodiment, a plurality of ATM terminals 20 are connected to the main unit 10 of the ATM switching system.

Main device 10 includes a control unit (hereinafter referred to as CC).
U), a terminal interface unit 12 having a plurality of ports for connecting a plurality of ATM terminals 20, a voice type conversion unit 13, and a connection between these units 11, 12, 13. A
And a back board 14 having a TM switch 141.

As described above, in the example described below, the A of audio data as an extension call between ATM terminals is used.
Although the description is omitted because the exchange is performed by the TM cell, the main device 10 usually includes, for example, an INS (Informat
ion Network System) A line interface unit for connecting a line is connected.

The ATM terminal 20 has an AAL type 1 type and an AAL type 5 type.
For data communication, there are dedicated to voice communication and dedicated to data communication. Whether the ATM terminal 20 is one of these types is determined by a power-up sequence when the ATM terminal 20 is connected to the main device 10.
Registered in. When the voice data to be included in the ATM cell is data in the form of an IP packet, the information to that effect is also transmitted to the main unit 10 during the power-up sequence.
Registered and managed.

At the time of this power-up sequence,
The main device 10 gives an extension number to the ATM terminal connected to the port of the terminal interface unit 12,
This extension number is associated with the registration information,
Manages TM terminals. Each ATM terminal has an ATM
Address and IP address are also assigned,
Manages these also corresponding to each ATM terminal.

Therefore, main unit 10 determines what kind of ATM terminal connected to each of the plurality of ports of terminal interface unit 12, that is, AAL type 1 or type 5, and It recognizes whether it is dedicated to voice communication or data communication.

If the audio data transmitted from the own terminal is compressed in the case of being transmitted in the form of an IP packet, the data is compressed in a setup message from the terminal prior to the communication. This includes information for notifying the main apparatus 10 of the fact.

In the example of FIG. 2, it is assumed that an AAL type 1 ATM terminal and an AAL type 5 ATM terminal dedicated to voice communication are connected to the terminal interface unit 12. In this specification, in order to distinguish between both ATM terminals having different AAL types, AAL type 1 A
ATM terminal 20A, AAL type 5 ATM
The terminal is an ATM terminal 20B.

The ATM terminal 20A for AAL type 1 is:
ATM terminal control unit 21, CLAD2 of AAL type 1
2, a CLAD 23A of AAL type 5, a PCM codec unit 24, and a handset 25.

The CLAD 22 divides fixed speed information for voice and the like transmitted by the ATM terminal 20 into 48-byte units, assembles them into AAL type 1 ATM cells,
Further, the received AAL type 1 ATM cell is decomposed to restore voice information and the like. Also, CLAD23A
Is for assembling and disassembling AAL type 5 ATM cells of control information transmitted to and received from the CCU 11. The PCM codec unit 24 decodes the audio PCM data from the CLAD 22 to restore an analog audio signal and supplies the analog audio signal to the handset 25, or the PCM encoding of the audio signal from the handset 25 and supplies it to the CLAD 22. .

The ATM terminal 20B for AAL type 5 is:
ATM terminal control unit 21 and AAL type 5 CLAD2
3B, a PCM codec unit 24, and a handset 25. The CLAD 23B of this ATM terminal 20B is
Assembling not only ATM cells of control information to be transmitted to and received from the CCU 11 but also AAL type 5 ATM cells of voice data;
For disassembly.

Next, the main device 10 will be described. CC
U11 includes a CCU control unit 110 and a CLAD 111 that assembles and disassembles cells of control data. The CCU control unit 110 includes a microcomputer.

The back board 14 is an ATM cell bus 14
2 which is connected to the ATM switch 141. C
The CLAD 111 of the CU 11 is used for assembling and disassembling the control data cells.
The switch 141 is connected.

The terminal interface unit 12 includes a terminal interface control unit 121, an ATM cell address conversion control unit 122, and an AAL type 5 CLAD 123.

The terminal interface control section 121 has a CL
The control data is exchanged with the CCU control unit 110 through the AD 123, the system control bus 142 of the backboard 14, and the CLAD 111 of the CCU 11.

The ATM cell address conversion control unit 122
It is connected to a plurality of ATM terminals 20 and to the terminal interface control unit 121 and the CLAD 123. Further, the ATM cell address conversion control section 122 is further connected to the ATM cell bus 142.

This ATM cell address conversion control section 122
Performs address conversion control of a destination when cells of control information are transmitted and received between the plurality of ATM terminals 20 and the CCU 11, and performs voice information and the like between the ATM terminal 20 and the voice type conversion unit 13. Control of the address conversion of the destination when the cell is transmitted / received. Further, although not shown,
The ATM cell address conversion control unit 122 outputs the ATM terminal 2
It also performs address conversion control of the destination when transmitting and receiving cells such as voice information between the INS interface unit 12 and the INS interface unit 12.

The voice type conversion unit 13 includes a voice type conversion control unit 131 and an AAL type 1 CLAD 13.
2, an AAL type 5 CLAD 133, an audio memory 134, and a data memory 135 other than audio. The audio type conversion control unit 13 has other additional components in hardware, such as a transmission timing control unit described later, but is omitted in FIG.

The voice type conversion control unit 131 of the voice type conversion unit 13 uses the voice memory 134 and the non-voice data memory 135 to convert the ATM cells of the AAL type 1 voice data into the ATM cells of the AAL type 5 voice data. The cell is changed to a cell, and conversely, the ATM cell of AAL type 5 voice data is changed to an ATM cell of AAL type 1 voice data.

FIG. 3 shows the voice type conversion unit 13.
From the ATM cell of AAL type 1 voice data, A
It is a schematic diagram in the case of converting AL type 5 voice data into ATM cells.

In the case of FIG. 3, the audio type conversion unit 13 receives the AAL that arrives every 5.875 msec.
The type 1 ATM cell is decomposed by the CLAD 132 to extract audio data, and is stored in the audio memory 134 through the audio type conversion control unit 131. Then, the voice type conversion control unit 131 cuts out the voice data from the voice memory 134 for the AAL type 5 ATM cell, and
Send to 33. The CLAD 133 generates an ATM cell of AAL type 5 voice data using the received voice data. Then, the generated ATM cells of the AAL type 5 voice data are set so that the voice is not interrupted.
It is transmitted from the audio type conversion unit 13 at regular intervals, for example, every 5 msec. This transmission timing control is performed by the voice type conversion control unit 131.

In the AAL type 1, SAR-PD
Although a sequence number is assigned for each U (and therefore for each ATM cell), this sequence number is not assigned for AAL type 5. In the AAL type 5, continuous display is performed using the ATM layer-user display embedded in the payload type (PT) of the ATM layer, and variable length data is assembled. That is, the continuous display is not set for the cell corresponding to the end of the variable length data, and the continuous display is set for the other cells. And
A 32-bit CRC code (error detection code) is added to the last cell of the variable-length data to ensure the normality of a series of audio frames. The AAL type 5 ATM cell in FIG. 3 corresponds to this last cell.

In the AAL type 5 ATM cell of FIG. 3, CPCS is a common part convergence sublayer, UU is a display between users, CPI is a common part identifier, and LI is
Indicates the length, and CRC32 indicates the 32-bit CR described above.
This is a C code.

In this embodiment, the CCU 11
When there is a call request for an extension call from the M terminal 20, the ATM terminal 20 of the other party sends the ATM requesting the call.
When the terminal and the AAL type are different, control is performed such that the voice type conversion unit 13 is interposed in the communication path of both ATM terminals.

As will be described in detail later, when an extension call is made from the AAL type 1 ATM terminal 20A to the AAL type 5 ATM terminal 20B,
AAL type 1 AT from type 5 ATM terminal 20B
When making an extension call to the M terminal 20A, conversion of the AAL type of the ATM cell of the voice data is performed.

In this embodiment, the ATM cell bus is shared with the system control bus, so that the CCU 11 is not provided with a system control bus for unit control.
Units 12, 13 and ATM terminal 20 (2
0A, 20B). That is, C
Between the CU 11 and each of the units 12 and 13 and the ATM terminal 2
The local control data between 0 is also expressed as ATM cells as A
It is configured to be able to transmit and receive through the TM cell bus.

For this reason, in this embodiment, a PVC (fixed virtual channel) is previously set as a system control path or a terminal control path for each unit or ATM terminal, and an ATM cell is set on each PVC. Transmits and receives unit control data and terminal control data between each unit and the CCU or between the ATM terminal and the CCU through the ATM switch.

The transmitted and received control data is SS
COP (Service Specific Connection Oriented Proto
col; a communication protocol such as a service-dependent connection-type protocol) enables communication with a higher-level application as well as data transmitted and received through the system control bus, and enables various controls.

The setting of the PVC as the system control path or the terminal control path is performed, for example, when the system is started up, using the VPI value and the VCI value previously determined as the power-up code specific to the unit or the terminal, and using the CCU 15.
And the transmission and reception of ATM cells between each unit and terminal.

Next, some aspects of communication of voice data between ATM terminals of different AAL types using ATM cells will be described in detail.

[Case 1]: ATM from ATM terminal 20B
Connection Sequence to M Terminal 20A In this case 1, first, when there is a request for an extension call from the AAL type 5 ATM terminal 20B, the CCU 11
A sequence for connecting B and the audio type conversion unit 13 is executed. Thereafter, when there is an extension call by designating the extension number of the destination ATM terminal 20A at the ATM terminal 20B, the ATM via the voice type conversion unit 13 is transmitted.
Forming a communication path between the terminal 20B and the ATM terminal 20A,
Enables extension calls.

[Connection Between ATM Terminal 20B and Voice Type Conversion Unit 13] FIG. 4 shows a case where an AAL type 5 ATM terminal 20B sends an extension call using an ATM cell of voice data to an AAL type 1 ATM terminal 20A. FIG. 9 is a diagram showing a connection sequence between the ATM terminal 20B and the voice type conversion unit 13 which is necessary as advance preparation in the case.

In each of the sequence diagrams shown below, terminals and units are indicated by abbreviations for simplification of description, and VEA is an AAL type 1 ATM terminal 20A.
And VEB stores AAL type 5 ATM terminal 20B in 2
5MU and MBU are the control units of the terminal interface unit 12 to which the ATM terminals 20A and 20B are connected, and VTU is the voice type conversion unit 1
3 and CCU indicate CCU11, respectively.

The sequence diagram of FIG. 4 shows A for voice communication only.
This is a connection sequence with the VTU when, for example, an extension button is operated in the AL type 5 ATM terminal 20B (VEB). The VTU includes a plurality of circuits including an AAL type 1 port and an AAL type 5 port. FIG. 4 shows ports and extension numbers of one of the circuits 1.

That is, the setup message of the extension call request from the VEB at this time is sent to the CCU 11 through the terminal interface unit 12. The destination number (called number) “999zzzz” included in the setup message indicates that the voice communication terminal is to be the communication partner. Further, the setup message at this time includes the terminal ID of the ATM terminal 20B and the information of the AAL type.

The CCU 11 identifies from the setup message that the request is for an extension voice communication from an AAL type 5 VEB. At this time, the CCU 11
"CALL PR" indicating that setup has been accepted
Then, a process of returning "OC" to the VEB and causing the VTU to intervene in the extension communication path between the VEB and the VEA is thereafter executed.

That is, the CCU 11 sends an extension incoming call setup message to the VTU. The extension number at this time is "316" which specifies the port for the AAL type 5 of the VTU. Then, after recognizing that the circuit 1 including the port is in use, the VTU recognizes the connection message “C
ONN ”to the CCU 11. Upon receiving this connection message, the CCU 11 sends the response “CONNACK” to the VT
Send to U.

Next, the CCU 11 transmits the VEB and the VTU
A procedure for setting an SVC (Switched Virtual Channel) between the two is performed. That is, first, a channel setting command is sent to the terminal interface unit 25MU on the VEB side. Terminal interface unit 25MU
Returns a channel setting response to the CCU 11. Also,
The CCU 11 uses the circuit 1 to send a channel setting command for receiving audio data to the VTU. In response to this, the VTU sets the receiving channel and returns a channel setting response to the CCU 11.

After that, the CCU 11 sends a connection message to the VEB through the terminal interface unit.
The VEB returns a connection confirmation message to the CCU 11. As described above, the AAL type 5 ATM terminal 20B and the VTU
The connection channel setting through the ATM switch 141 is completed.

As a result, the AAL type 5 ATM terminal 20 B
The preparation for forming an extension communication path to the AL type 1 ATM terminal is completed. Also, this connection sequence
As described later, this AAL type 5 ATM terminal 2
0B to the same AAL type 5 ATM terminal, when it is necessary to convert voice data into IP packets or compress data, the voice type conversion unit 13 AAL type 5 A
It is also a preparation for setting up an extension communication path to the TM terminal.

[Voice Connection Between VEB and VEA] Next, FIG. 5 shows a sequence for forming a voice communication path from VEB to VEA and making an extension call in case 1.

That is, as shown in FIG. 5, when the VEB sends an extension call setup message designating VEA (AAL type 1 ATM terminal 20A) as the terminating terminal, the setup message is sent to the CCU 11 via the VTU. Sent. As described above, the setup message includes information notifying that the audio data is transmitted in the form of an IP packet or that the audio data is compressed.

C that received this setup message
The CU 11 sends a setup message to the VEA, and returns “CALL PROC” indicating that the VEB has accepted the setup via the VTU. Also,
The CCU 11 receives “CALL PROC” indicating that the setup from the VEA has been received.

Then, based on the information (terminating = extension 207) of the called terminal included in the setup message, the CCU 11 determines that the VAL of AAL type 1 whose AAL type is different from VEB.
The EA (ATM terminal 20A) is identified as the destination.
That is, when the VEA is connected to the CCU 11,
Since the AAL type information and the like are registered in advance, it is identified from the registration information that the other party's VEA is an AAL type 1 ATM terminal.

Therefore, the CCU 11 sets an SVC between the VTU and the VEA via the ATM switch 141. That is, a channel setting command is sent to the MBU, a response command is received from the MBU, and at the same time, a communication channel setting command is sent to the VTU.
The response command is received from the VTU. After that, VE
A connection command from A is received, and a response command to the connection command is transmitted to the VEA. Thereby, V
A communication channel is formed between the AAL type 1 port of the TU and the VEA.

At this time, the channel setting command for the VTU from the CCU 11 includes AAL type 5 AT
When the audio data transmitted by the M cell is data of the IP packet format, or when the audio data of the IP packet is compressed, the information instructing the disassembly / assembly of the IP packet, the decompression / decompression of the audio data, Information for instructing compression is included.

After that, the CCU 11 sends a connection command to the VEB via the VTU, and receives a response command to the connection command from the VEB via the VTU. As described above, an extension communication path via the VTU is formed between the VEB (ATM terminal 20B) and the VEA (ATM terminal 20A).

Then, AAL type 5 A from VEB
The TM cell is converted to an AAL type 1 ATM cell by the VTU and then sent to the VEA.
The L type 1 ATM cell is converted to an AAL type 5 ATM cell by the VTU and then sent to the VEB.

In this case, if the voice data transmitted in the AAL type 5 ATM cell is in the form of an IP packet, in the VTU, the AAL type 5 to AAL type
At the time of converting ATM cells of voice data into type 1, the voice data obtained by decomposing AAL type 5 ATM cells is decomposed into IP packets, and then converted into AAL type 1 ATM cells. To Conversely, AA
When performing conversion of ATM cells of L type 1 to AAL type 5 voice data, voice data obtained by decomposing AAL type 1 ATM cells is assembled into IP packets and then converted to AAL type 5 ATM cells. Convert it.

If the audio data transmitted in the AAL type 5 ATM cell is in the form of an IP packet and is compressed, the ATM of the audio data from AAL type 5 to AAL type 1 is transmitted. At the time of cell conversion, after decomposing the IP packet and decompressing the compressed voice data, conversion to AAL type 1 ATM cells is performed. Also, when converting ATM cells of audio data from AAL type 1 to AAL type 5, after compressing the audio data and assembling the IP packet, conversion to AAL type 5 ATM cells is performed. To do.

The processing in the voice type conversion unit 13 (VTU) during the communication of the voice data will be described later in detail.

[Case 2]: AT from ATM terminal 20A
Connection sequence to M terminal 20B In this case 2, since the terminal on the transmitting side is of AAL type 1, the CCU 11 transmits the extension to make it clear that the communication is voice communication.
, The setup message including the special called number “999zzzz” indicating that the communication is voice communication as in Case 1 is not sent, and the setup message including the extension number “204” of the other party's VEB as the called number is not sent. A message is sent.

As described above, AAL type 1 A
From VEA which is TM terminal, VE which is AAL type 5
When there is a request for an extension call to B, the CCU 11 first
A sequence for performing channel connection between the VEA and the audio type conversion unit 13 is executed.

When the channel connection between the VEA and the audio type conversion unit 13 is completed, the CCU 1
1 executes a sequence for channel connection between the VTU and the communication partner VEB. And CCU
11 waits for a response from the VEB, and sets a communication channel between the VTU and the VEA. This allows VEA and V
Mutual extension calls can be made to and from the EB via the VTU.

[Connection between ATM Terminal 20A (VEA) and ATM Terminal 20B (VEB)] FIG. 6 shows a case 2 where an AAL type 1 ATM terminal 20A transmits an AAL type 5 ATM terminal 20B. A of data
It is a figure which shows the connection sequence at the time of making the call of the extension call by TM cell.

First, a setup message (including a VEB extension number as a called number,
(Including information originating from AAL type 1) is transmitted through the terminal interface unit 12 (MBU) to the CC.
It is sent to U11.

The CCU 11 identifies that the ATM terminal of the communication partner is the AAL type 5 from the called party number included in the setup message and the registration information on the ATM terminal having the called number. Then, the AA of the calling ATM terminal included in the setup message
From the L type information, it is identified that the AAL types of both terminals are different.

Then, the CCU 11 sends the setup to the VEB to the VTU, and sets “CALL PROC” indicating that the setup has been accepted to the VEB.
To return. Upon receiving this setup, the VTU decides to use circuit 1, and places the setup in CCU11.
To return. CCU11 which received the reply of this setup
Converts the destination number from the VEB extension number to an ATM address, and returns "CALL PROC" to the VTU.

Thereafter, the CCU 11 sends an extension call setup message including the ATM address as a called number to the VEB through the terminal interface unit 25MU. Then, the VEB sends back the message “CONN” of the line connection to the CCU 11, and the CCU 11 sends the response “CONNACK” to the
Send to VEB through MU.

The CCU 11 subsequently sends VEB and VTU
A procedure for setting an SVC (Switched Virtual Channel) between the two is performed. That is, first, a channel setting command is sent to the terminal interface unit 25MU on the VEB side. Terminal interface unit 25MU
Returns a channel setting response to the CCU 11. Also,
The CCU 11 uses the circuit 1 to send a channel setting command for receiving audio data to the VTU. In response to this, the VTU sets the receiving channel and returns a channel setting response to the CCU 11.

Thereafter, the CCU 11 sends a connection message to the VEB through the terminal interface unit.
As described above, the AAL type 5 ATM terminal 20 on the called side
The setting of the connection channel between B and the VTU through the ATM switch 141 is completed.

[Connection Between ATM Terminal 20A (VEA) and ATM Terminal 20B (VEB)] In this case 2, the sequence shown in FIG. 7 is performed following the sequence shown in FIG. That is, as described above, when the setting of the connection channel between the ATM terminal 20B of the AAL type 5 on the called side and the VTU through the ATM switch 141 is completed,
The VTU sends a setup message from the VEA to the VEB. The VEB sends “CALL PROC” indicating that the setup has been accepted to the VTU. VTU
Transfers the “CALL PROC” to the CCU 11.

[0086] The CCU 11 controls the A between the VTU and the VEA.
An SVC via the TM switch 141 is set. That is, a channel setting command is sent to the MBU, and a response command is received from the MBU.
A communication channel setting command is sent to the VTU, and a response command is received from the VTU.

Thereafter, the VTU transfers the VEB alert message from the VEB to the CCU 11, and the CCU 11 sends the alert message to the VEA through the MBU. The VTU sends a VEB connection message from the VEB to the CC.
Transfer to U11. The CCU 11 receives this and sends a connection message to the VEA through the MBU. Then, C
The CU 11 sends a VEB connection confirmation message to the VTU, and the VTU transfers the message to the VEB. Furthermore, CC
U11 receives the connection confirmation message from the VEA.

As described above, VEA and VE with VTU interposed
A communication path with B is generated. In this case 2, the CCU 11 recognizes the VEB of the called party from the information designating the called party included in the setup message from the VEA, and recognizes the VEB of the called party from information previously registered in the CCU 11 for the VEB. , VEB is AAL type 5, and when the voice ATM cell recognizes the voice data of the IP packet format or the voice data of the IP packet is compressed, the CCU 11 determines in the sequence diagram of FIG. When a channel is set from the CCU 11 to the VTU, information to that effect is given. Upon receipt of this, the VTU receives the CCU for the audio data in the same manner as described above.
The processing according to the instruction information from 11 is executed.

[Disconnection of Connected Channel from VEB] FIG. 8 is a sequence diagram when a disconnection request is issued from the VEB. That is, a disconnection request (VEB
-DISC; when a request to disconnect the connection between the VEB and the VTU is generated, the VTU transfers the request to the CCU 11. Upon receiving this, the CCU 11 sends a release message to the VTU.
To the VEB via. VEB sends the response to VTU
To the CCU 11 via.

The CCU 11 receives this, and outputs VEA and V
To release the connection with the TU, send a channel release message to the VTU and receive its response from the VTU.
Also, the CCU 11 sends a release message to the VEA through the MBU, and receives a response from the VEA through the MBU. Then, a channel release message and its response message are exchanged between the CCU 11 and the MBU.

Thereafter, the CCU 11 receives the release message from the VEB via the 25 MU, and
Return to VEB through 5MU. And CCU 11
To release the channel connection between the VEB and the VTU, the CCU 11 sends a channel release message to the 25MU and receives its response from the 25MU.
Then, the CCU 11 exchanges a release message with the VTU, exchanges a channel release message and its response between the VTU and the CCU, and releases the connection between the VEB and the VTU.

[Disconnection of Connected Channel from VEB] FIG. 9 is a sequence diagram when a disconnection request is issued from the VEA. That is, when a release request is generated from the VEA, the CCU 11 receives the request, sends a VEB-DISC to the VEB via the VTU, and sends a response to the release request to the VEA. And CCU11 is VEA
A channel release command is sent to the MBU to release the connection on the side, and a response of the channel release is received from the MBU. Then, the CCU 11 receives the release message from the VEB via the VTU, and
Send to VEB via TU. After that, CCU 11
To release the connection between the VEA and the VTU, it sends a channel release message to the VTU and receives its response from the VTU.

CCU 11 receives the release message from VEB and sends a response message to VEB. Then, the CCU 11 exchanges a channel release message and a response message between the CCU 11 and the 25 MU in order to release the channel between the VEB and the VTU.

After that, the CCU 11 exchanges a release message with the VTU, and then exchanges a channel release command and its response, thereby completing the disconnection process.

In the following, in the key telephone system including the main unit 10 described above, voice type conversion at the time of an extension call performed between ATM terminals using the communication path formed by the above-described cases 1 and 2 is described. The flow and processing of the audio signal in the unit 13 will be described for various cases.

[Case A. FIG. 10 shows a case where audio data is not compressed or packetized.
ATM terminal of AAL type 1 from ATM terminal of L type 5
FIG. 3 is a block diagram for explaining an example of processing executed by a voice type conversion unit 13 when a voice ATM cell is sent to a terminal.

As shown in FIG. 10, the AAL type 5 fixed-speed voice A transmitted through the ATM switch 141
The TM cell is the CLAD1 of the voice type conversion unit 13.
The audio data is decomposed at 33 and stored in the audio memory 134. The audio data stored in the audio memory 134 is cut out for the AAL type 1 by the audio type conversion control unit 131, as opposed to the case of FIG.
Supplied to Then, the data is converted into an AAL type 1 ATM cell by the CLAD 132 and transmitted to the destination via the ATM switch 141.

FIG. 11 illustrates an example of processing executed by the voice type conversion unit 13 when a voice ATM cell is sent from the AAL type 1 ATM terminal to the AAL type 5 ATM terminal in the case A. It is a block diagram for performing.

As shown in FIG. 11, the ATM switch 14
AAL type 1 fixed speed voice ATM that has passed through
The cell is a CLAD 132 of the voice type conversion unit 13.
, And the audio data is stored in the audio memory 134. The audio data stored in the audio memory 134 is cut out for the AAL type 5 by the audio type conversion control unit 131 as shown in FIG.
3 is supplied. Then, the data is converted into an AAL type 5 ATM cell by the CLAD 133 and output to the VPI / VCI check unit 137.

Then, the voice type conversion control section 131
The SVC information (set of VPI / VCI) is set in the VPI / VCI check unit 137 from the table 136 in which the information of the SVC for the voice ATM cell given from the CCU 11 is stored. , The fixed speed data transmission circuit 138 is used.

The VPI / VCI check section 137 is constituted by hardware. The fixed speed data transmission circuit 138 constitutes transmission timing control means and is not shown in FIG. 2, but is provided as hardware for the ALL type 5 ATM cell sent from the CLAD 133.

Therefore, VPI / VCI check unit 1
The AAL type 5 ATM cells from 37 are supplied to a fixed rate data transmission circuit 138. The fixed speed data transmission circuit 138 transmits the ATM cell of the AAL type 5 to the ATM switch 14 at a fixed speed of 5 msec cycle in this example.
1 to the AAL type 5 ATM terminal.

[B. A case where voice data of an AAL type 5 ATM cell is converted into an IP packet,
Conversion to ATM cell of type 1] In this case, in B
The audio type conversion unit 13 performs conversion on audio data as shown in FIG. That is, AA
The ATM cell of L type 1 is decomposed to extract audio data and store it in the audio memory. Next, an IP packet is generated by adding an IP header to the audio data. Then, an AAL type 5 ATM cell is generated for this IP packet. Conversely, the AAL type 1 ATM cell of the AAL type 5
The conversion to the TM cell is performed in the reverse procedure.

FIG. 13 shows that in this case B, when a voice ATM cell is sent from an AAL type 5 ATM terminal that handles voice data of an IP packet to an AAL type 1 ATM terminal, the voice type conversion unit 13 executes the process. FIG. 9 is a block diagram for explaining an example of processing to be performed.

As shown in FIG. 13, the AAL type 5 voice ATM cell of the IP packet format that has passed through the ATM switch 141 is decomposed by the CLAD 133 of the voice type conversion unit 13 and then the IP packet decomposing unit 2
At 01, the IP packet head is removed, the packet is decomposed, and voice data is extracted.

The audio data in the audio memory 134 is absorbed by the fluctuation absorbing buffer 202, and the fluctuation in the unit of the IP packet at the time of reception is absorbed. It is cut out for type 1 and supplied to the CLAD 132. And CL
The data is converted into an AAL type 1 ATM cell by the AD 132 and transmitted to the destination via the ATM switch 141.

Conversely, FIG. 14 shows that in this case B, A
AAL of IP packet from ATM terminal of AL type 1
FIG. 3 is a block diagram for explaining an example of processing executed by a voice type conversion unit 13 when a voice ATM cell is sent to a type 5 ATM terminal.

As shown in FIG. 14, the ATM switch 14
1 is decomposed by the CLAD 132 of the audio type conversion unit 13, and the audio data is stored in the audio memory 134. The audio data stored in the audio memory 134 is
The voice type conversion control unit 131 cuts out the packet for AAL type 5, and the IP packet
After the packet is assembled, it is supplied to the CLAD 133. And AAL type 5 AT with CLAD133
It is converted to M cells and output to the VPI / VCI check unit 137.

The voice type conversion control unit 131
In this case, from the table 136 in which the information of the SVC for the voice ATM cell given from the CCU 11 is stored,
The SVC information (VPI / VCI set) is
/ VCI check unit 137, and the ATM cell of the IP packet is processed as data. Therefore, the ATM switch 141 is used without using the fixed speed data transmission circuit 138.
And send it to the other party's ATM terminal.

The IP packet decomposing unit 201 and the packet assembling unit 203 are configured by software.

[C. AAL type 5 ATM cell voice data is IP packetized and compressed, and AAL
FIG. 15 shows a case where an AAL type 5 ATM terminal in which compressed voice data is converted into an IP packet and communicated in the case C in FIG.
FIG. 4 is a block diagram for describing an example of processing executed by a voice type conversion unit 13 when a voice ATM cell is sent to an L-type 1 ATM terminal.

In this case, the audio memory 134
And a fluctuation absorbing buffer 202, a decompression processing unit 204 for compressed audio data is provided. The audio data decompressed by the decompression processing unit 204 is supplied to the fluctuation absorbing buffer 202. Others are the same as those in FIG.

Next, FIG. 16 shows that in this case C, A
A handling an AAL type 5 ATM cell of an IP packet of compressed voice data from an AL type 1 ATM terminal
FIG. 3 is a block diagram for explaining an example of processing executed by a voice type conversion unit 13 when a voice ATM cell is sent to a TM terminal.

In this case, the audio memory 134
A voice compression processing unit 205 is provided between the voice compression conversion unit 131 and the voice type conversion control unit 131. Then, the audio compression processing unit 20
5, the data in the voice memory 134 is compressed, and then the IP packet assembling unit 20 through the voice type conversion control unit 131.
3 and assembled as an IP packet. Others are the same as those in FIG.

[D. This is communication between ATM terminals that handle AAL type 5 ATM cells.
FIG. 17 shows a case where an AAL type 5 (data is not packetized) voice ATM terminal is used to transmit an AAL type 5 A packet of an IP packet.
FIG. 3 is a block diagram for explaining an example of processing executed by a voice type conversion unit 13 when a voice ATM cell is sent to a TM terminal.

As shown in FIG. 17, the ATM switch 14
The fixed-rate voice ATM cell of AAL5 that has passed through 1 is decomposed by the CLAD 133 of the voice type conversion unit 13 and the voice data is stored in the voice memory 134. The audio data stored in the audio memory 134 is
The voice type conversion control unit 131 cuts out the packet for AAL type 5, and the IP packet
After the packet is assembled, it is supplied to the CLAD 133 again. And AAL type 5 with CLAD133
Is converted to an ATM cell of VPI / VCI check unit 1
37. Then, the voice type conversion control unit 13
1 is, in this case, the audio A given from the CCU 11
Table 136 in which SVC information for TM cells is stored
Then, the SVC information (set of VPI / VCI) is set in the VPI / VCI check unit 137, and the ATM cell of the IP packet is processed as data. Therefore, the ATM switch is not used without using the fixed speed data transmission circuit 138. It is sent to the other party's ATM terminal through 141.

FIG. 18 shows an AAL type 5 ATM terminal of an IP packet data from an AAL type 5 ATM terminal.
FIG. 3 is a block diagram for explaining an example of processing executed by a voice type conversion unit 13 when a voice ATM cell is sent to a TM terminal.

As shown in FIG. 18, an AAL type 5 voice ATM cell of an IP packet passed through the ATM switch 141 is transmitted to the CL of the voice type conversion unit 13.
After being decomposed by the AD 133, the IP packet decomposing unit 201
Then, the IP packet head is removed, the IP packet is decomposed, and audio data is extracted.

After the fluctuations are absorbed by the fluctuation absorbing buffer 206, the sound data in the sound memory 134 is cut out for the AAL type 5 by the sound type conversion control unit 131 and supplied to the CLAD 133. Then, the data is converted into an AAL type 5 ATM cell by the CLAD 133 and transmitted to the destination via the ATM switch 141.

[E. AAL type 5 ATM cell voice data is IP-packetized and compressed, and AAL
FIG. 19 is a diagram showing a case where an AAL type 5 (data is not packetized) voice ATM terminal is converted to an AAL type 5 of an IP packet of compressed voice data in the case E in this case E. FIG. 6 is a block diagram for explaining an example of processing executed by a voice type conversion unit 13 when a voice ATM cell is sent to the ATM terminal of FIG.

In the case of FIG. 19, in the case of FIG. 17, the audio data read from the audio memory 134 is subjected to audio compression by the audio compression
It is sent to the voice type conversion control unit 131. Others are the same as those in FIG.

FIG. 20 shows the processing performed by the voice type conversion unit 13 when a voice ATM cell is transmitted from an AAL type 5 ATM terminal to an AAL type 5 ATM terminal for data of an IP packet accompanied by compression. FIG. 8 is a block diagram for describing an example of a process to be performed.

As shown in FIG. 20, in this case, FIG.
In the case of No. 8, the decompression processing unit 204 of the compressed voice is provided between the voice memory 134 and the fluctuation absorbing buffer 206, and the decompression processing of the voice data compressed by the decompression processing unit 204 is performed. Different from the case. Others are the same as in the case of FIG.

[Other Embodiments] The above example is a case where the present invention is applied to the case of an extension call of an ATM key telephone system. Also, the present invention can be applied to the case of a call with a telephone terminal through a digital telephone line.

FIG. 21 shows a configuration diagram of a key telephone system for explaining the case. That is,
In FIG. 21, reference numeral 15 denotes a line interface unit which connects the main device 10 to a digital telephone line, for example, INS (In).
formation Network System) for connecting to the line 30.

As described above, since the line interface unit 15 is connected to the INS line 20 in this example, the INS interface 151, the INS interface control unit 152, and the AAL type 1 CLAD 153 are provided.
And an AAL type 5 CLAD 154.

The INS interface control unit 152
AL type 5 CLAD 154 and backboard 14
The INS interface 151 is controlled by transmitting and receiving control data to and from the CCU control unit 110 through the.

The INS interface 151 is connected to the INS line 30, and the INS interface control unit 152
Under the control of the INS line 30 to perform the interface processing. The CLAD 153 is used to assemble and store cells such as voice information transmitted and received through the INS interface 151.
Perform disassembly. CLAD 153 is the back board 14
It is connected to the TM cell bus 142.

As described above, in the case of this example, the voice data from the digital line is transmitted through the ATM switch 141 in the main unit 10 by the AAL type 1 voice ATM cell. Therefore, in the description of the above-described embodiment, the line interface unit 15 is the AAL type 1
In the same way as in the case of an extension call, the A
Calls can also be made using an AL type 5 ATM terminal.

[0130]

As described above, according to the present invention, voice communication becomes possible between an AAL type 5 ATM terminal and an AAL type 1 ATM terminal.

Further, even if the AAL type 5 is the same, a voice ATM cell is transmitted / received in a format in which voice data is packetized or voice data is further compressed.
Communication can be performed without any problem between those transmitting and receiving voice ATM cells without packetization and compression.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a communication sequence in an embodiment of an ATM switching device according to the present invention.

FIG. 2 is a block diagram of an embodiment of an ATM switching device according to the present invention.

FIG. 3 is a diagram for explaining voice AAL type conversion processing in the embodiment of the ATM switching apparatus according to the present invention;

FIG. 4 is a diagram showing a connection sequence when a call is made from an AAL type 5 ATM terminal to an AAL type 1 ATM terminal in the embodiment of the ATM switching apparatus according to the present invention.

FIG. 5 is a diagram showing a communication sequence of a voice ATM cell performed between an AAL type 5 ATM terminal and an AAL type 1 ATM terminal, following FIG. 4;

FIG. 6 is a diagram showing a connection sequence when a call is made from an AAL type 1 ATM terminal to an AAL type 5 ATM terminal in the embodiment of the ATM switching apparatus according to the present invention.

FIG. 7 is a diagram showing a communication sequence of a voice ATM cell performed between the AAL type 1 ATM terminal and the AAL type 5 ATM terminal, following FIG. 6;

FIG. 8 is a diagram showing a sequence in a case where a communication path connected in FIG. 4 or FIG. 6 is disconnected.

FIG. 9 is a diagram showing a sequence in the case of disconnecting the communication path connected in FIG. 4 or FIG. 6;

FIG. 10 is a diagram showing an example of processing in the audio type conversion unit of FIG. 2;

FIG. 11 is a diagram showing another example of the processing in the audio type conversion unit in FIG. 2;

FIG. 12 is a diagram for describing an example of processing in a voice type conversion unit when voice data is converted into IP packets to form AAL type 5 ATM cells.

FIG. 13 is a diagram showing another example of the processing in the audio type conversion unit in FIG. 2;

FIG. 14 is a diagram showing another example of the processing in the audio type conversion unit in FIG. 2;

FIG. 15 is a diagram illustrating another example of the processing in the audio type conversion unit in FIG. 2;

FIG. 16 is a diagram illustrating another example of the processing in the audio type conversion unit in FIG. 2;

FIG. 17 is a diagram illustrating another example of the processing in the audio type conversion unit in FIG. 2;

FIG. 18 is a diagram illustrating another example of the processing in the audio type conversion unit in FIG. 2;

FIG. 19 is a diagram showing another example of the processing in the audio type conversion unit of FIG. 2;

FIG. 20 is a diagram showing another example of the processing in the audio type conversion unit in FIG. 2;

FIG. 21 is a block diagram showing another embodiment of the ATM switching apparatus according to the present invention.

FIG. 22 is a diagram illustrating the structure of an ATM cell.

FIG. 23 is a diagram showing a sequence when a call is made from an AAL type 5 ATM terminal to an AAL type 1 ATM terminal in the conventional case.

[Explanation of symbols]

Reference Signs List 10 Main unit 11 Control unit 12 Terminal interface unit 13 Voice type conversion unit 14 Backboard 15 Line interface unit 20A ATM terminal of AAL type 1 20B ATM terminal of AAL type 5 110 CCU control unit 121 Terminal interface control unit 131 Voice type conversion control Unit 122 ATM cell address conversion control unit 111, 123, 133, 23A, 23B AAL type 5 CLAD 132, 22 AAL type 1 CLAD

Continued on the front page (72) Inventor Keisei Yasushima 6-10-13 Nakanobu, Shinagawa-ku, Tokyo Inside Daiko Electric Manufacturing Co., Ltd. (72) Inventor Junji Asakura 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Japan Within Telegraph and Telephone Co., Ltd. (72) Inventor Hitoshi Maeda 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo F-term within Telegraph and Telephone Co., Ltd. 5K026 EE06 5K030 GA05 HA10 HB01 HB14 JA06 JT01 KA01 KA02 KA19 LA07

Claims (11)

[Claims] When a communication path is formed, communication data is voice data, and A of an ATM cell of voice data from a calling side is transmitted.
AL type and A of ATM cell of voice data to called side
An identification means for identifying that the data type is different from the AL type; a voice type conversion means for converting an AAL type of an ATM cell of the voice data; and the identification means, wherein the communication data is voice data; When it is determined that the AAL type of the ATM cell of the voice data from the AAL is different from the AAL type of the ATM cell of the voice data to the called side, the voice type conversion means is interposed in the communication path, and AAL of cell
Control means for causing a type conversion to be performed. 2. The ATM switching device according to claim 1, wherein the identification means performs the identification based on information included in a setup message from the calling terminal and information registered in advance. Characteristic ATM switching equipment. 3. The ATM switching device according to claim 1, wherein said voice type conversion means converts said ATM cell to AA.
An ATM switching device comprising transmission timing control means for transmitting the converted AAL type 5 ATM cell at a fixed rate when converting from L type 1 to AAL type 5. 4. The ATM switching device according to claim 1, wherein the AAL type 5 ATM cell of the voice data is obtained by packetizing voice data of a plurality of ATM cells or more. A packet assembling / disassembling means for assembling or disassembling a packet of the audio data; and a second identification means for identifying that the audio data is packetized, The control means controls the packet assembling / disassembling means on the basis of the identification result of the second identifying means.
The voice data decomposed by the decomposing means is converted into AAL type 1 A
Converted to TM cells, or
The voice data in which the packet has been assembled from the voice data of the AAL type 1 ATM cell by the decomposing means
An ATM switching device for converting into an AL type 5 ATM cell. 5. The ATM switching apparatus according to claim 4, further comprising: a buffer for absorbing a fluctuation when receiving the packet-separated voice data, wherein the voice type conversion means includes a voice data in which the fluctuation is absorbed. An ATM switching device for converting an AAL type 1 ATM cell into an ATM cell. 6. The ATM switching device according to claim 4, wherein the voice data to be packetized and transmitted includes a case where data is compressed, and the voice data is expanded or compressed. And a third identification means for identifying that the packetized audio data is compressed, wherein the control means identifies the result of the third identification means. And controlling the audio data decompression / compression means based on the following. If the audio data is compressed, the audio type conversion means outputs the audio data decompressed by the audio data decompression / compression means, The AAL type 1 ATM cell is converted to the AAL type 1 ATM cell.
An ATM switching device wherein the M cell voice data is compressed by the voice data decompression / compression means, and the packetized data is converted into the AAL type 5 ATM cell. 7. A terminal interface unit to which an ATM terminal such as a key telephone is connected, an AAL type of an ATM cell of voice data is a type 1,
A voice type conversion control unit that converts between the type 5 and the type 5, a control unit that controls the entire system including the terminal interface unit and the voice type conversion unit, the control unit, the terminal interface unit, An ATM switch for interconnecting the voice type conversion control unit with the voice type conversion control unit, wherein the control unit is configured such that, when a communication path is formed, communication data is voice data;
AAL type of ATM cell of voice data from calling side and A of voice data to called side through ATM switch
Identification means for identifying that the AAL type of the TM cell is different from the AAL type of the ATM cell for voice data from the calling side and the AAL type of the ATM cell for voice data to the called side; When the voice type conversion unit identifies that the ATM cell is different, the voice type conversion unit is interposed in a communication path between the calling side and the called side through the ATM switch, and the ATM cell is transmitted to the ATM cell by the voice type conversion unit. A
Control means for performing mutual voice communication between the calling side and the called side by performing the conversion of the AL type. 8. The ATM switching device according to claim 7, wherein the ATM terminal connected to the terminal interface unit transmits voice data to be transmitted to the communication partner through the ATM switch in an AAL type with the ATM terminal. When making a call request for communication that requires the use of a different ATM cell, the control unit, based on the identification result of the identification means, places the ATM switch between the ATM terminal and the voice type conversion unit. Setting a first communication channel via the ATM switch between the communication partner included in the call request and the voice type conversion unit. ATM to do
Exchange equipment. 9. The ATM switching device according to claim 7, wherein said communication partner is another ATM terminal connected to a terminal interface unit. 10. The ATM switching device according to claim 7, wherein said terminal interface unit is connected to a digital telephone line, converts voice data from said digital telephone line into AAL type 1 ATM cells, and passes through said ATM switch. A line interface unit for performing voice communication with an ATM terminal connected to the ATM terminal. When voice communication is performed between the line interface unit and an ATM terminal that performs voice communication using AAL type 5 ATM cells, The ATM unit, wherein the voice type conversion unit is interposed in a communication path between the line interface unit through the ATM switch and the ATM terminal, thereby enabling an intercommunication. Exchange equipment. 11. A terminal interface unit to which an ATM terminal is connected and voice data obtained by decomposing an AAL type 5 voice ATM cell are subjected to processing in accordance with a control instruction, and the processed voice data is A voice type conversion unit for converting to an AAL type 5 ATM cell; a control unit for controlling the entire system including the terminal interface unit and the voice type conversion unit; a control unit; the terminal interface unit; An ATM switch for interconnecting between a type conversion control unit and an ATM switch, wherein the control unit converts communication data into voice data when a call is made from the ATM terminal. And identifying that the ATM cell from the calling side is AAL type 5. Means, when the identification means identifies that the communication data is voice data and the ATM cell from the calling side is AAL type 5, the ATM terminal on the calling side and the voice type conversion. A first communication path forming means for forming a communication path between the voice type conversion unit and the called side via the ATM switch;
Second communication path forming means for forming a communication path via an M switch; information on the voice data included in information at the time of calling for specifying a destination from the ATM terminal; and information on the destination. And instruction information supply means for supplying instruction information of necessary processing on audio data to the audio type conversion unit from information on audio data to be transmitted to the destination. apparatus.