JPH11331174A - Key telephone system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a key telephone set, without damaging a high-class service for the key telephone set even without using any dedicated control line, while connecting the key telephone set and a standard terminal to the same interface. SOLUTION: A base unit 10 is made into an asynchronous transfer mode(ATM) exchange system. An ATM terminal, such as ATM key telephone set or ATM standard terminal, is connected to respective terminal interface units 13 of the same configuration. When the ATM terminal is connected to the terminal interface unit 13, a control unit 11 recognizes whether the connected ATM terminal is the ATM standard terminal or the ATM key telephone set, and when the connected ATM terminal is the ATM key telephone set between the ATM key telephone set and the control unit 11, a characteristic fixed virtual channel(PVC) is set so as to communicate control information through the set PVC between the ATM key telephone set and the control unit 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key telephone system in which a key telephone and a communication terminal other than a key telephone such as a standard telephone can be connected.

[0002]

2. Description of the Related Art As shown in FIG. 12, a key telephone system comprises a main unit 1 containing one or more telephone lines 2 and a plurality of key telephones 3 connected thereto. Then, for the main device 1, a standard telephone 4, etc.
There are many devices having a configuration to which other standard terminals can be connected.

[0003] In this specification, the standard terminal differs from the key telephone 3 in that it does not include an LED (light emitting diode) that is turned on, off, and blinks under the control of the main unit 1. The various key telephone service functions cannot be received.

[0004] The main device 1 of the conventional key telephone system includes:
A control unit 5 configured by a microcomputer and controlling the entire main device 1; an exchange unit 6 such as a communication line switch; a line interface unit 7; a key telephone interface unit 8; and a standard terminal interface unit 9. The telephone line 2 is connected to a line interface unit 7.

Button telephone interface unit 8
Has a plurality of ports, and the key telephone 3 is connected to each port. The key telephone 3 is transmitted from the control unit 5 through the key telephone interface unit 8 to the LE.
Control of turning on, off, and blinking of D and control for various key telephone service functions are received. For this control, a dedicated control line is connected between the key telephone 3 and the key telephone interface unit 8 in addition to the communication line, as shown by a broken line in the figure.

The standard telephone 4 does not require control from the control unit 5 and is connected to the standard terminal interface unit 9. No control line is required between the standard telephone 4 and the standard telephone interface unit 9.

[0007]

As described above, in the conventional key telephone system, when the key telephone 3 and the standard telephone 4 are connected, it is necessary to use separate interface units dedicated to each. . In order to realize various advanced button telephone service functions with the key telephone 3, dedicated control lines are required between the key telephone 3 and the key telephone interface unit 8.

After the key telephone 3 is connected to the key telephone interface unit 8 and the standard telephone 4 is connected to the standard terminal interface unit 9 and installed, there is a place where each telephone can be installed. This is limited, and there is a problem in that the user can freely rearrange the telephone.

In view of the above, the present invention allows a key telephone and a standard terminal such as a standard telephone to be connected to the same interface, enables free arrangement of the telephone, and provides a dedicated control line. An object of the present invention is to enable control of a key telephone without impairing advanced services for the key telephone without using the key telephone.

[0010]

The switching system required for the next-generation network is to cope with an increase in information transmission speed, to have a variable transmission speed function, to be able to transmit multimedia information, and the like. ATMs (AsynchronousTransfer)
Mode) An exchange method is provided.

In this ATM system, information sent from the transmission side to the reception side is divided into 48 bytes, a 5-byte header is added to the data, 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.

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

FIG. 13 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. 13 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 to form a virtual path, Communication is performed.

In the key telephone system according to the present invention, the above-described ATM exchange system is applied to a main unit of the key telephone system. In the key telephone system according to the present invention, a first interface unit connected to a digital telephone line, a second interface unit connected to an ATM terminal such as an ATM button telephone or an ATM standard terminal, and Key telephone system, comprising: a control unit for controlling the entire system including the first and second interface units; and an ATM switch for interconnecting the control unit and the first and second interface units. And when the ATM terminal is connected to the second interface unit, the control unit determines whether the connected ATM terminal is the ATM key telephone or another ATM terminal. And the connected ATM terminal recognizes the ATM key telephone When it is between the ATM key telephone and the control unit, a unique PVC (Permanent Virtual Ch
annel; fixed virtual channel), and control information is communicated between the ATM key telephone and the control unit through the set PVC.

[0017]

According to the present invention having the above construction, the control data from the control unit for the ATM key telephone is A
It is configured to be able to transmit and receive as a TM cell through an ATM cell bus. That is, there is no need to provide a dedicated control line.

An ATM terminal connected to a second interface unit for an ATM terminal (in this specification, the ATM terminal includes an ATM key telephone and an ATM standard terminal) is an ATM terminal. The control unit recognizes whether the terminal is a key telephone or an ATM standard terminal at the time of connection. This recognition, AT
In the case of an M-button telephone, a specific control signal can be notified to the main unit at the time of connection, and the control unit can detect this signal.

The control data path between the ATM key telephone and the control unit is set as a PVC (fixed virtual channel) when the ATM key telephone is connected to the main unit. The PVC is a virtual path that does not exist as a physical cable (machine string) but is determined by defining the VCI and VPI of the header of the ATM cell.

As described above, in the key telephone system of the present invention, a dedicated control line between the key telephone and the main unit can be dispensed with, and the key telephone and the standard terminal have the same interface. Can be connected to.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a key telephone system according to the present invention will be described below with reference to the drawings.

[Exemplary Configuration of Button Telephone System] FIG.
1 shows an example of the configuration of a key telephone system according to this embodiment.
In this example, two ATM key telephones 3 are used as terminals.
1, 32 and one standard telephone 33 are connected. As an example of a digital telephone line, INS (Informatio
n Network System) The line 20 is connected and configured.

Main device 10 includes a control unit (hereinafter referred to as CC).
U), a line interface unit 12 for connecting to the INS line 20, and the ATM button telephones 31, 32 and the standard telephone 3 as ATM terminals.
3 and a terminal interface unit 13 for connecting each of them to the main device 10.
ATM switch 1 for interconnecting 2 and 13
And a back board 14 having the same.

The terminal interface unit 13 has an AT
A plurality of, for example, six ports for connecting M terminals are provided. As described later, any of the ports can accommodate either an ATM key telephone or an ATM standard terminal.

The ATM key telephones 31 and 32 have the same configuration. As shown in FIG. 2, an ATM key telephone control unit 301 and a cell assembling / disassembling unit (hereinafter referred to as CLA) are provided.
D (called Cell Assembly and Disassembbly) 302
And 303, and a numeric keypad 3 for dial input
04, a group of various function buttons 305, and a group of LEDs 306 that are turned on, blinked, and turned off according to control from the main device 10.

The CLAD 302 divides fixed speed information such as voice transmitted from the ATM key telephone into 48-byte units, assembles them into cells, and decomposes received cells to restore voice information and the like. Also, CLAD30
Reference numeral 3 is for assembling and disassembling cells of control information to be transmitted to and received from the CCU 11.

In the figure, each block of the CLAD describes an AAL (ATM Adaptation Layer) protocol type, and AAL1 (AAL type 1) performs cell assembly / disassembly of fixed information such as voice information. , AAL
No. 5 (AAL type 5) is for assembling and disassembling cells such as confirmation type connection type data such as control information exchanged with the CCU 11.

The ATM standard telephone 33 has substantially the same configuration as the ATM key telephone, but does not include the LEDs 306 that are controlled by the main unit 10 and the buttons 305 for various service functions.

ATM key telephones 31, 32 and AT
The M standard telephone set 33 includes the terminal interface unit 13
And connected to the main device 10.

The CCU 11 determines whether the ATM key telephones 31 and 32 are connected (accommodated) to each port of the terminal interface unit 13 as described later.
It recognizes whether the standard telephone 33 has been connected (accommodated), and between the ATM key telephones 31 and 32,
The CCU 11 sets a PVC so that local control data is transmitted to the ATM key telephones 31 and 32 using the set PVC.

In the key telephone system of this example, for example, an incoming call from the INS line 20 is received by the main unit 10 and notified to each ATM terminal by a control data cell, and one of the ATM terminals responds. When the AT
The path between the M terminal and the INS line 20 is exchanged so that the main unit 10 generates the path. Also, regarding the outgoing call, the main unit 10 receives the call request cell from the ATM terminal, and
The vacancy of the line 20 is confirmed, and the call from the ATM terminal is transmitted to the partner terminal through the vacant line channel.

At the time of communication, voice information and the like from the INS line 20 are converted into cells by the line interface unit 12, and the cells are transmitted through the ATM switch 141 of the backboard 14 to the terminal interface unit 13.
Is sent to each of the ATM terminals 31, 32, 33 through Cells such as voice information from the ATM terminals 31, 32, and 33 are sent to the line interface unit 12 through the terminal interface unit 13, the ATM switch 141, and the ATM cell bus 142, and the cells are decomposed.
The original audio information is reconstructed and sent to the INS line 20.

In the key telephone system as described above, the CCU 11, the line interface unit 12, the terminal interface unit 13, and the CCU 11
As described above, it is necessary to exchange control information between the ATM key telephones 31 and 32. In order to transmit and receive the control information, control is usually performed by a unique control software interface using a unique physical system control bus (control line).

On the other hand, in this embodiment, the AT
By sharing the M cell bus 142 with the system control bus, the CCU 11 can control the units 12, 13 and the ATM key telephones 31, 32 without providing a special unit control system control bus. . That is, not only the control data between the CCU 11 and each of the units 12 and 13 but also the local control data between the CCU 11 and the ATM key telephones 31 and 32 are A
It is configured to be able to transmit and receive as a TM cell through the ATM cell bus 142.

For this reason, in this embodiment, a PVC is used in advance as a system control path or a terminal control path between the CCU 11 and each of the units 12 and 13 or between the CCU 11 and the ATM key telephones 31 and 32.
(Fixed virtual channel) is set, and each PVC
Above, the unit control data and the terminal control data are transmitted and received between the units 12 and 13 and the CCU 11 or between the ATM key telephones 31 and 32 and the CCU 11 through the ATM switch 141 by the ATM cell.

The transmitted and received control data is SS
COP (Service Specific Connection Oriented Proto
A communication protocol such as col (service dependent connection type protocol) makes it possible to communicate with a host application and perform various controls in the same manner as data transmitted and received through a conventional system control bus.

The setting of the PVC as the system control path or the terminal control path is performed, for example, when the system is started or when the ATM key telephone is connected (at the time of setup).
A VPI value and a VCI value determined in advance as a power-up code specific to a unit or an ATM button telephone.
This is performed by transmitting and receiving ATM cells between the CU 11 and each unit or ATM key telephone. This P
The setting of the VC will be described later in detail.

The detailed configuration of the main unit 10 including the transmission part of the control information will be described below.

That is, as shown in FIG. 3, the CCU 11 of the main unit 10 of this embodiment
And AAL type 5 for assembling and disassembling the cell of control information
CLAD 111 is provided. The CLAD 111 is connected to the ATM cell bus 142 of the backboard 14.
The CCU control unit 110 includes a microcomputer.

The backboard 14 has no physical system control bus, and in this embodiment, the backboard 14 is physically connected to the ATM switch 141 and the ATM switch 141.
It comprises a cell bus 142.

As described above, the line interface unit 12 is an INS (Information Network) in this example.
System), the INS interface 121, the INS interface control unit 122, and the AAL type 1 CLAD 123 as shown in FIG.
And an AAL type 5 CLAD 124, and the CLADs 123 and 124
42.

The INS interface control unit 122 outputs
By transmitting and receiving control data to and from the CCU control unit 110 through the LAD 124 and the ATM cell bus 142 of the back board 14 and the CLAD 111 of the CCU 11,
The INS interface 121 is controlled.

The INS interface 121 is connected to the INS line 20 and the INS interface control unit 122
Under the control of the INS line 20, the interface process with the INS line 20 is performed. The CLAD 123 is used to assemble and store cells such as voice information transmitted and received through the INS interface 121.
Perform disassembly.

FIG. 5 shows the terminal interface unit 13.
1 shows an example of the configuration. The terminal interface unit 13 includes a terminal interface control unit 131 and an ATM
Cell address conversion control section 132 and AAL type 5 C
LAD 133 is provided.

The terminal interface control section 131 has a CL
ATM cell bus 1 of AD133 and backboard 14
42, and further exchanges control data with the CCU control unit 110 through the CLAD 111 of the CCU 11.

The ATM cell address conversion control section 132
It is provided corresponding to each of the plurality of ports 134 provided in the terminal interface unit 13. That is,
The ATM terminal connected to the port 134 is connected to the ATM cell address conversion control unit 132. Further, the ATM cell address conversion control section 132 is connected to the terminal interface control section 131 and the CLAD 133. Further, the ATM cell address conversion control section 132 is further connected to an ATM cell bus 142.

This ATM cell address conversion control section 132
Is the port 1 of the terminal interface unit 13
In addition to performing the address conversion control of the destination at the time of transmitting and receiving the cell of the control information between the ATM terminal accommodated by the CCU 11 and the cell information such as voice information between each ATM terminal and the line interface unit 12, It performs address conversion control of the destination at the time of transmission and reception.

In order to be able to transmit and receive line control data such as call control and call control between the ATM terminal accommodated in the terminal interface unit 13 and the CCU 11 by using the ATM cell bus, it is necessary to perform the following steps. , CCU11
From ATM cell bus 142, CLAD111, CLA
D133 via the ATM cell address conversion control unit 1
In 32, routing information to the CCU 11 as a communication destination (tag addressed to the CCU 11 and accommodation position information of the ATM terminal accommodated in each port 134 of the terminal interface unit 13) is set. Thereby, A between each of the ATM terminals 31, 32, 33 and the CCU 11
Transmission and reception can be performed via the TM switch 141 and the ATM cell bus 142.

That is, the cell from the CCU 11 to which the tag having the destination of the ATM terminal is added is changed by the ATM cell address conversion control unit 132 into a cell (no tag) whose address is converted to the ATM terminal. , Are sent to the respective ATM terminals. A cell of control information such as call information from an ATM terminal is provided with a tag addressed to the CCU 11 by the ATM cell address conversion control unit 132, converted in address, and sent to the CCU 11 through the ATM cell bus 142 and the ATM switch 141. . Note that the terminal interface unit 13 in this embodiment is
The ATM cell address conversion control unit 132 does not need to have the CLAD function since all inputs and outputs are ATM cells, and simply performs tag addition / detection and VPI / VCI conversion / attachment of the header of the ATM cell. What is necessary is just to have the function to perform.

[Setting of PVC between Units of Main Unit 10] Next, in the system shown in FIG. 1, a system control path between each interface unit 12, 13 and CCU 11 and ATM key telephones 31, 32 and CC
The setting of PVC as a terminal control path to U11 will be described.

FIG. 6 shows the terminal interface unit 13.
FIG. 4 is a sequence diagram for explaining setting of a PVC between the CCU 11 and the CCU 11; The sequence shown in FIG. 6 is automatically executed when the system in which the main apparatus 10 is powered on is started.

That is, in this example, the CCU 11
[VPI / V] of the header of the ATM cell is used as a power-up code between the terminal and the terminal interface unit 13.
CI] is set to [0/8] and this PVC
, Control information is transmitted and received as shown in the sequence of FIG. 6, and a PVC for control information transmission between the CCU 11 and the terminal interface unit 13 is set thereafter.

FIG. 7 shows an example of cell data transmitted and received at this time.
Shown in In FIG. 7, for convenience of explanation, as shown in FIG. 7A, the header portion shows only [VPI / VCI],
The information of the information field is added to this.

When the power of the main unit 10 is turned on, the terminal interface control unit 131 of the terminal interface unit 13 sends the [VPI / VC
ATM cell in which the value of [I] is [0/8] and the information field contains the unit accommodation position of the terminal interface unit 13, the unit identification information, the power-up request information, and the like (see FIG. 7B) Through the ATM cell bus 142 and the ATM switch 141.
Send to 11.

The CCU control unit 110 receives this via the CLAD 111 and sends it to the terminal interface unit 1.
Recognize power up of 3. And the CCU control unit 1
Reference numeral 10 denotes [VPI for setting a PVC for transmitting and receiving control data to and from the terminal interface unit 13.
/ VCI] and the ATM cell (see FIG. 7C) of the unit control VPI setting request including the power-up confirmation information in the information field are transferred to the CLAD111-ATM switch 141 and the ATM cell bus 142-CLAD13.
3 to the terminal interface unit 13.

In the example of FIG. 7, [VPI / VC
The value of [I] is [1/12]. At this time, the value of [VPI / VCI] of the cell header is [0/8].

The terminal interface unit 13 having received the unit control PVC setting request cell recognizes that the power up of the own unit has been received,
The unit control PVC is set. Then, when the setting is completed, the terminal interface control unit 131
Through the LAD 133, [VPI / VC
I] is [0/8] and the information field includes the unit accommodation position of the terminal interface unit 13, the unit identification information, the power-up setting completion information, and the like (see FIG. 7D). ), ATM
C through cell bus 142 and ATM switch 141
Transmit to CU11.

The AT for which the unit control PVC setting is completed
The CCU 11 receiving the M cell recognizes that the setting of the unit control PVC of the terminal interface unit 13 has been completed. As a result, control data is transmitted and received between the CCU 11 and the terminal interface unit 13 by the set PVC by the ATM cell bus 142 through the CLAD 133, the ATM switch 141, and the CLAD 111 with ATM cells.

FIG. 8 shows the terminal interface unit 13.
2 shows a sequence of transmission and reception of control data between the CCU 11 and the CCU 11. This transmission / reception uses ATM cells, and the ATM switch 141 and the ATM cell bus 142
[VPI / VCI] of the header
Is [1/12] previously set as described above.
And P determined by the value of [VPI / VCI]
Control data is transmitted and received on the VC.

FIG. 7E shows an example of control data addressed from the terminal interface unit 13 to the CCU 11.
FIG. 7F shows an example of control data addressed from the CCU 11 to the terminal interface unit 13.

The line interface unit 12 and the CC
6, the value of [VPI / VCI] of the header of the cell transmitted and received between the two units (the terminal interface unit 13 and the CCU 11) in the same manner as in the sequence of FIG. PV during
C is set, and the unit control PVC is set. After that, the CCU 11 and the INS interface unit 1 are connected to the ATM cell bus through the CLAD 124, the ATM switch 141, and the CLAD 111 with the ATM cells by the set PVC.
2, control data is transmitted and received.

The setting of the PVC between the units 12 and 13 and the CCU 11 is performed for all the interface units mounted on the main unit 10. In this case,
The CCU 11 assigns different [VPI / VCI] values to all units mounted on the main device 10.
As a result, an inter-unit control bus replacing the special system control bus can be realized by the ATM cell bus.

The communication protocol for transmitting and receiving control data between each of the units 12 and 13 and the CCU 11 is as follows.
For example, SSCOP is used to ensure the reliability of control data. Also, the CLP of a cell transmitted and received when setting the above-mentioned PVC is set to “0”, and the discard priority is set to be low. This suppresses an increase in traffic such as retransmission of a control signal.

In the above example, the PVC is set by using a PVC predetermined for power-up when the main apparatus 10 is started up. However, the present invention is not limited to this. .

For example, when the installation of the main device 10 is started,
The operator may set the [VPI / VCI] value that defines the PVC between each of the units 12, 13 and the CCU 11, respectively.

The CCU control unit 110, the terminal interface control unit 131 and the INS interface control unit 1
A control line may be provided between the control line 21 and the control line, and [VPI / VCI] values for defining the PVC may be set through the control line in the same manner as described above.

[PVC between ATM key telephone and CCU]
Next, setting of PVC for transmitting and receiving control data with the CCU 11 when the ATM terminal is an ATM key telephone will be described. As described below, after being connected to the port 134 of the terminal interface unit 13, the PVC is set and the CCU 1
1 allows local exchange of control data with the terminal interface unit 1
3 can be connected to both the ATM standard telephone 33 and the ATM key telephones 31 and 32.

A is assigned to terminal interface 13 of main device 10.
A processing routine in the CCU 11 when a TM terminal is connected will be described with reference to a flowchart in FIG.

When the ATM terminal 30 is connected to one port 134 of the terminal interface unit 13 of the main unit 10 and its power is turned on (step S10).
1), the CCU 11 is a terminal interface unit 13
It recognizes to which of the plurality of ports 134 the ATM terminal is connected (step S102). Then, the ATM terminal connected at this time is temporarily recognized as an ATM standard terminal (step S103).

When the connected ATM terminal is an ATM key telephone, a setup message including a power-up start instruction is generated after the connection and power supply of this ATM terminal. On the other hand, A such as an ATM standard telephone
In the case of the TM standard terminal, this setup message does not occur.

Therefore, in the next step S104, it is determined whether or not a setup message including power-up has arrived from the ATM terminal connected to the port 134. If it has not arrived, the port 1 in step S103
It is determined that the terminal connected to the terminal 34 is an ATM standard terminal, and the process exits from this processing routine.

In step S104, the port 134
When it is determined that a setup message including power-up has arrived from the ATM terminal connected to the
The M terminal recognizes that the terminal is the ATM key telephone, and in the next step S106, sets the PVC as the control data transmission path to be used between the connected ATM key telephone and the CCU 11. .

After setting the PVC, the next step S10
7, the terminal control message is exchanged between the CCU 11 and the connected ATM key telephone, and the terminal number of the ATM key telephone included in the terminal control message is set. Recognize it as a number and exit this processing routine.

FIG. 10 shows the setting of the PVC for controlling the key telephone and the power-up sequence in this case.

That is, when an ATM terminal is connected to the terminal interface unit 13 of the main unit 10, a layer 2 link is established between the two and the connected ATM is connected.
The terminal is temporarily recognized as being an ATM standard terminal. When the connected ATM terminal is an ATM key telephone, a setup message including power-up information is transmitted from the ATM key telephone by an ATM cell.

At this time, the ATM button telephone and the CCU 1
1 is transmitted and received via the ATM cell address conversion control unit 132 of the terminal interface unit 13 as described above. That is, [VP] of the cell
[I / VCI] is converted in the ATM cell address conversion control unit 132. The transmission and reception of cells between the CCU 11 and the terminal interface unit 13 are performed in a state where a tag is added to the cell.

In this example, when the ATM key telephone is powered up (connected to the main unit 10), the ATM
The value of [VPI / VCI] of the cell between the key telephone and the terminal interface unit 13 is previously set to, for example, [0/5] as a standard, and between the terminal interface unit 13 and the CCU 11. The value of [VPI / VCI] of the cells between them is set to, for example, [1/5].

As described above, when the ATM key telephone is connected to one port 134 of the terminal interface unit 13 of the main unit 10 as shown in FIG. / V
CI] is [0/5], and a cell including information notifying the start of power-up in the information field is CLAD3.
3 to the terminal interface unit 13.

When the terminal interface unit 13 receives the power-up start cell from the ATM key telephone, the ATM cell address conversion control section 132 of the port to which the ATM key telephone is connected receives the [VPI / VCI] of the cell. Convert the value to [1/5],
11 to the ATM cell bus 142, AT
The power-up start notification cell is transmitted to the CCU 11 through the M switch 141.

Upon receiving this, the CCU 11 receives the ATM.
Recognize the start of powering up the key telephone. Then, a unique PVC is assigned to the connected ATM key telephone. In this case, the setting of the PVC is performed by setting the value in the information field of [VPI / VCI] of the header of the ATM cell used for transmitting control data. The value of [VPI / VCI] to be set is, as described above, the [VPI / VCI] of the cell header between the CCU 11 and the terminal interface unit 13.
VCI], the terminal interface unit 13 and A
[VPI / VC of the header of the cell with the TM terminal 30
I].

In the example of FIG. 10, [0/20] is set as the value of [VPI / VCI] of the cell header between the terminal interface unit 13 and the ATM key telephone, and the CCU 11 and the terminal interface unit 13
[1/20] is set as the value of [VPI / VCI] in the header of the cell between. The latter is a terminal interface unit 1 containing an ATM key telephone.
The VPI / VCI value used as a user frame is set in the ATM cell address conversion control unit 132 of No. 3 in FIG.

[VPI / VCI]
Is transmitted from the CCU 11 to the ATM key telephone and the terminal interface unit 13, respectively.
For this reason, the CCU 11 requires the ATM key telephone to:
A cell in which the value of [VPI / VCI] of the cell to be transmitted / received to / from the terminal interface unit 13 is included in the information field is sent, and information of the conversion of the [VPI / VCI] is sent to the terminal interface unit 13 To

As shown in FIG. 10, first, the CCU 11
Should notify the ATM key telephone [VPI / VC
A cell including the value of I] in the information field is transmitted. That is, the value of [VPI / VCI] in the header is [1/5]
In the information field, a cell in which a value for setting a PVC for control information, [VPI / VCI] = [0/20], is added with a tag whose destination is the terminal interface unit 13 is added. The data is sent from the CCU 11 to the terminal interface unit 13 accommodating the connected ATM key telephone through the ATM switch 141 and the ATM cell bus 142.

This cell is received by the ATM cell address conversion control section 132 of the terminal interface unit 13. Then, the ATM cell address conversion control section 132
Converts the value of [VPI / VCI] in the header to A
It is transmitted to the TM button telephone. That is, the ATM cell address conversion control unit 132 of the terminal interface unit 13 converts the value of [VPI / VCI] of the received cell into [0/5] and removes the tag. Then, the cell is sent to the connected ATM key telephone.

The ATM key telephone receives this cell, analyzes its information field, and executes the [VPI / VC
The value [0/20] of I] is recognized as PVC setting data as a path for communicating control data with the CCU 11. Then, the ATM key telephone sets the following CC
When communicating control data with U11, processing is performed so that the value of [VPI / VCI] in the header portion is transmitted as [0/20]. The ATM key telephone has a software application for this processing.

The CCU 11 then sends the converted value of [VPI / VCI] to be notified to the terminal interface unit 13, that is, the terminal interface unit 13 and the AT.
[VPI / VCI] value [0
/ 20], the terminal interface unit 13 and the CCU
The cell in which the information instructing the conversion with the value [1/20] of [VPI / VCI] between [11] and [11] is transmitted in the information field. A tag is given to this cell, and its destination is the terminal interface unit 13. In this case, the cell path uses the VPC set as the control data path between the terminal interface unit 13 and the CCU 11 described with reference to FIG. 6, and the [VPI / VCI] of the header of the cell is used. Is [1/12]
It is.

The terminal interface unit 13 converts the cell of the notification of the converted value of [VPI / VCI] into the CLAD
133, holds the converted value of the [VPI / VCI], and when the control information is transmitted and received between the connected ATM key telephone and the CCU 11,
[PI / VCI] value is converted using the held value. And the terminal interface unit 13
Sends a cell in which the information of the setting completion is included in the information field to the CCU 11 through the ATM cell bus 182 through the CLAD 133. The path at this time is also the set PVC, and the value of [VPI / VCI] of the cell is:
[1/12].

Then, communication is performed between the CCU 11 and the ATM key telephone using the PVC set as described above, and the setting of the user frame connection is completed.

After that, the ATM button telephone notifies the CCU 11 of the completion of the power-up setting including its own terminal number through the set PVC route.
That is, the value of [VPI / VCI] in the header of the cell of the power-up notification from the ATM key telephone is [0/2]
0], which is converted to [1/20] by the ATM cell address conversion control unit 132 of the terminal interface unit 13 and transferred to the CCU 11.

CCU 11 recognizes the power up of the ATM key telephone and receives the AT.
Recognize the terminal number of the M button telephone. And CCU
11 is a terminal interface unit 13 and an ATM
An ATM cell having broadcast information, installation data, and volume information as information fields is transmitted to the key telephone set by the set PVC. In addition, CCU11
Sends the time correction information to the terminal interface unit 13 and the ATM key telephone in the same manner. Thereafter, the ATM key telephone enters the state of normal operation display.

Thus, the power up of the ATM key telephone is completed. Since then, this ATM key telephone LE
Local control such as D control and state information from the ATM key telephone are transmitted to the ATM switch 141 and the ATM cell bus 142 through the set PVC path.
Is done through

FIG. 11 shows this ATM key telephone and CC
It is a figure which shows the sequence of transmission / reception of control data with U11. Although omitted in FIG. 11, the control data transmitted and received between the terminal interface unit 13 and the CCU 11 is a tagged cell.

The same processing as described above is performed when an ATM terminal is connected to another port 134 of the terminal interface unit 13 and the power is turned on. When the ATM terminal connected to the port 134 is an ATM standard terminal, the CCU 11 recognizes that it has been connected, but does not perform PVC setting. Further, when the ATM terminal connected to the port 134 is an ATM key telephone,
In the same manner as described above, the other A connected to the main device 10
A PVC different from that of the TM key telephone is set, and local control data with the CCU 11 is transmitted and received through the ATM cell bus by the set PVC.

Thus, according to this embodiment, both an ATM standard telephone and an ATM key telephone can be connected to the terminal interface unit 13.
That is, the terminal interface unit 13 uses the ATM
It can be used commonly for standard terminals and ATM key telephones. Therefore, the connection between the ATM standard terminal and the ATM key telephone with respect to the main unit 10 is not restricted as described at the beginning, and the user can connect the ATM standard terminal and the ATM key telephone even after the system is installed. The position can be easily changed.

Further, a special control line for the ATM key telephone is unnecessary, and when the ATM key telephone is connected, a unique PVC is set, and the set PVC is set.
The control data can be exchanged with the CCU 11 through the CPU.

That is, according to this embodiment, the AT
Local control between the M-button telephone and the CCU 11 can also be performed using the ATM cell bus.
There is no need to provide a local control bus between the key telephone and the CCU, and cost can be reduced.

Although the above embodiment has been described in connection with the case where one line of the INS line is connected to the line interface unit 12, a plurality of lines can be accommodated in the line interface unit 12. It goes without saying that the present invention can be applied to a case where a plurality of lines are accommodated in the line interface unit 12.

Further, the ATM standard terminal is not limited to the ATM standard telephone, but may be a facsimile apparatus or a personal computer capable of transmitting and receiving ATM cells.

Further, between the CCU 11 and the terminal interface unit and the line interface unit,
The control data may be performed by providing a system control bus instead of performing the control data through the ATM control bus as in the above-described embodiment.

[0100]

As described above, according to the key telephone system of the present invention, a key telephone and a standard terminal can be connected to a common terminal interface unit. Therefore, the arrangement of the key telephone and the standard telephone terminal can be freely set.

According to the present invention, control data can be transmitted and received between the ATM key telephone and the control unit through the ATM cell bus using the PVC set for each ATM key telephone. An exclusive local control bus is not required, and the ATM key telephone system can be configured at very low cost.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of an embodiment of a key telephone system according to the present invention.

FIG. 2 is a block diagram showing a configuration example of an ATM key telephone of the embodiment of the key telephone system according to the present invention;

FIG. 3 is a block diagram illustrating a configuration example of a control unit according to the embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration example of a line interface unit according to the embodiment of the present invention.

FIG. 5 is a block diagram illustrating a configuration example of a terminal interface unit according to the embodiment of the present invention.

FIG. 6 is a sequence diagram for explaining PVC setting between a terminal interface unit and a CCU in the embodiment of the present invention.

FIG. 7 is a diagram showing an example of data of an ATM cell transmitted and received between a CCU and an interface unit in the embodiment of the present invention.

FIG. 8 is a diagram showing a sequence of transmission and reception of control data between the terminal interface unit and the CCU in the embodiment of the present invention.

FIG. 9 is a flowchart showing a processing routine of a control unit when an ATM terminal is connected to a terminal interface unit in the embodiment of the present invention.

FIG. 10 is a sequence diagram for explaining exchange between the ATM key telephone and the control unit when the ATM key telephone is connected to the terminal interface unit in the embodiment of the present invention.

FIG. 11 is a sequence diagram for explaining exchange of control data between the ATM key telephone and the control unit in the embodiment of the present invention.

FIG. 12 is a block diagram showing a configuration example of a conventional key telephone system.

FIG. 13 is a diagram illustrating the structure of an ATM cell.

[Explanation of symbols]

 Reference Signs List 10 Main unit 11 CCU (control unit) 12 Line interface unit 13 Terminal interface unit 14 Backboard 141 ATM switch 142 ATM cell bus 20 INS line 31, 32 ATM button telephone 33 ATM standard telephone

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H04Q 3/00 H04Q 3/58 107 3/545 H04L 11/02 Z 3/58 107 11/20 B (72) Inventor Junji Asakura Nippon Telegraph and Telephone Corporation, 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo (72) Inventor Hitoshi Maeda 3-19-2, Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Osamu Kanakawa 24-4 Sakuragaoka-cho, Shibuya-ku, Tokyo Inside Nakayo Communication Aircraft Co., Ltd.

Claims (2)

[Claims] 1. A first interface unit connected to a digital telephone line, a second interface unit connected to an ATM terminal such as an ATM key telephone or an ATM standard telephone, and the first and second interface units A key telephone system, comprising: a control unit that controls the entire system including: an ATM switch for interconnecting the control unit and the first and second interface units; When the ATM terminal is connected to the second interface unit, the control unit recognizes whether the connected ATM terminal is the ATM key telephone or another ATM terminal, If the selected ATM terminal is an ATM key telephone, the ATM key A unique PVC (fixed virtual channel) is set between the handset and the control unit, and control information is communicated between the ATM key telephone and the control unit over the set PVC. A key telephone system characterized by: 2. The key telephone system according to claim 1, wherein whether the terminal connected to said second interface unit is said ATM terminal is a terminal connected to said second interface unit. A key telephone system that performs the setting based on a setup message from the user.