JP2600924B2 - Packet switching equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet switching device capable of accommodating an analog telephone for circuit switching.

[Conventional technology]

Since a packet switching system can multiplex and transmit a plurality of packet signals on one line, the line can be used effectively.

In a packet switch used in such a packet switching system, a CPU (central processing unit) generally performs switching connection by determining a connection destination from label information of a packet signal. However, in such a packet switch, high-speed switching processing cannot be performed because the CPU determines the connection destination for every packet. In addition, since the switching connection is performed for each packet signal, the time for transmitting the packet signal may vary greatly depending on the switching connection state of the packet switch.

For this reason, for a signal such as an audio signal which needs to be transmitted at a constant period in order to maintain a constant quality, transmission using a packet signal is not suitable. Therefore,
A circuit switch is conventionally used for voice signal communication, and analog telephones have not been accommodated in packet switches. That is, the conventional packet switch houses only a packet terminal that can output a packet signal of a predetermined format for a signal that does not cause a change in transmission time.

On the other hand, ATM (Asynchronous Transfer Mode) exchanges have been developed which enable high-speed packet exchange by performing packet signal exchange connection without using a CPU. According to this ATM exchange, it is possible to exchange and connect various information such as image information including voice signals.

FIG. 5 is for explaining the concept of such an ATM exchange.

The ATM switch 11 has a conversion table for adding a physical address to the packet signal in accordance with the call identification information.
The conversion table 12 is a memory circuit in which call identification information 13 and a corresponding physical address 14 are written by a CPU (not shown) every time a call is generated. A packet signal including user information described in an information area transmitted from a terminal device (not shown) and call identification information 13 described in a label area
16 is supplied to the conversion table 12. The physical address 14 corresponding to the call identification information 13 is added to the label area of the packet signal 16 in the conversion table 12. Physical address
The packet signal 17 to which 14 has been added is supplied to the switching connection device 18. Switching connection device 18, added physical address 14
The switching connection is performed by the switch circuit with reference to only the above, and the supplied packet signal 17 is output to a predetermined output line 19.

FIG. 6 is a diagram for explaining an exchange connection by switching of a shuffle type switch circuit as an example of a switch circuit of the exchange connection device 18.

The switch circuit 21 of the exchange connection device 18 has unit switches 22 each having two inputs and outputs arranged and connected according to a predetermined rule. For simplicity of description, a description will be given of a switch circuit 21 composed of unit switches 22 in four rows and three columns.
The unit switch 22 in each column of the switch circuit 21 switches according to the value of the bit string of the physical address 14 added in the conversion table 12. For example, each switch 22-1 in the first column of the unit switch 22 switches according to the value of the first bit of the physical address. When the corresponding bit of the physical address is “1”, each unit switch 22 switches to the lower output line,
In the case of “0”, the output line is switched to the upper output line.

If the numbers of the outgoing lines O _{0 to} O ₇ of the switch circuit 22 operating in this manner are expressed in binary numbers and added to the head of the packet signal as the physical address 14, no matter what incoming line the packet signal is input from, Output from the desired outgoing line. For example,
Packet signal 2 with the same physical address 14 “010” added
3,24 have been inputted from separate incoming lines I _5, I _7. Each of these packet signals 23 and 24 is a path indicated by a bold line and is switched upward by a unit switch in the first column, downward by a unit switch in the second column, and upward by a unit switch in the third column. and output the same to the output line O _2.

[Problems to be solved by the invention]

Such an ATM switch has a function of detecting the state of the analog telephone and the circuit switch, such as presence / absence of a loop due to off-hook, polarity of a power supply circuit, presence / absence of a call signal, etc., in order to switch and connect packet signals at high speed. Not.

Therefore, when an ATM switch is introduced instead of a circuit switch, there is a disadvantage that all analog telephones accommodated in the circuit switch must be packet terminals having the above functions. This has hindered the introduction of ATM exchanges.

Therefore, an object of the present invention is to provide a packet switching device capable of introducing an ATM switch without changing an analog telephone and another circuit switch.

[Means for solving the problem]

According to the present invention, (a) an ATM switch for switching and connecting a packet signal in accordance with its label information and (b) an analog telephone are accommodated, whether or not there is a loop of the analog telephone in an information area of the packet signal, and a subscriber circuit of a circuit switch. First state code means for writing a state code representing each state between the analog telephone and the circuit switch, which is composed of the polarity and presence / absence of a call signal to the analog telephone at the subscriber's circuit, and supplying the state code to the ATM switch; A first state identification for identifying a state code to be performed and controlling a polarity of a feed circuit of a subscriber circuit of the loop circuit switch of the analog telephone and a ringing signal for the analog telephone at the subscriber circuit to correspond to the state. An analog telephone terminal adapter having control means, and (c) an ATM exchange connected to a subscriber circuit of a circuit exchange. Second squared identification control means for identifying a state code from the packet signal supplied from the apparatus and controlling the state of the subscriber circuit so as to correspond to the state, and an information area of the packet signal corresponding to the state of the subscriber circuit. The packet switching apparatus is provided with an adapter for a circuit switch having second state code means for writing a state code and supplying the state code to the ATM switch.

That is, in the present invention, the presence or absence of a loop of the analog telephone as a state unique to the connection between the analog telephone and the circuit switch, the polarity of the power supply circuit of the subscriber circuit of the circuit switch, and the presence or absence of a call signal to the analog telephone at the subscriber circuit. The state code representing each state is written in the information area of the packet signal, and the ATM switch performs the switching connection based on the state code.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to examples.

FIG. 1 shows a schematic configuration of a packet switching device according to an embodiment of the present invention.

The packet switching device includes an ATM switch 31. ATM
The exchange 31 has the configuration shown in FIG. 5, and performs exchange connection using a label having call identification information. However, the switch circuit of the switching connection device may be a shuffle type shown in FIG. 6 or a shared memory type switch circuit (not shown). That is, the switch circuit used in the switching connection device may be any switching circuit that switches and connects according to the physical address added to the packet signal to determine the outgoing line.

The ATM switch 31 includes an analog telephone 32 and a circuit switch 33.
Exchange connection with a packet signal. Analog telephone 32
Is provided with an analog subscriber line interface (not shown) of the circuit exchange.

The analog telephone terminal adapter 34 is an analog telephone
32 are accommodated, and are connected to the ATM switch by connection lines 36 and 37. The analog telephone terminal adapter 34 includes a telephone state detection circuit 38 and a telephone state code circuit 39. The telephone state detection circuit 38 detects whether or not the analog telephone 32 is in a reap state, and controls the polarity of the power supply circuit and the calling circuit. On the other hand, the telephone state code circuit 39 converts the state of the analog telephone detected by the telephone state detection circuit 38 into a corresponding code, and identifies the state part of the packet signal from the ATM converter 31. .

The packet switching device includes a circuit switch adapter 41. Circuit switch adapter 41 connects to ATM switch 31 via connection line 4.
Connected by 2,43. Circuit switch adapter 4
1 is connected to the subscriber circuit 44 of the circuit switch 33.
The circuit exchange adapter 41 is a circuit exchange state detection circuit.
46, and a circuit switch status code circuit 47. The status code of the packet signal supplied from the ATM switch 31 is detected by the circuit switch status code circuit 47. In accordance with the state detected by the circuit switch state code circuit 47, the circuit switch state detection circuit 46 converts the state of the loop connection with the circuit switch 33.
Further, the circuit switch status detecting circuit 46 detects whether or not power is supplied from the circuit switch. The circuit switch status code circuit 47 converts the status code according to the presence or absence of the power supply.

FIG. 2 shows the format of a packet signal exchanged and connected by the ATM exchange 31.

The packet signal 51 includes a label area 52 and an information area 53. To the label area 52, call identification information and, in some cases, a physical address are added. A status code is written in a part of the information area. In this embodiment, the status code is a loop status code indicating whether or not the telephone has a loop.
54, a polarity state code 56 indicating whether the polarity is the normal state or the reversal state, and a call state code 57 indicating whether the call signal is turned on or off.

 Next, the operation of the packet switching device will be described.

FIG. 3 shows details of the terminal adapter 34 for an analog telephone. The telephone state detection circuit 38 is a relay DET
It has. The relay DET supplies a talk current to the analog telephone and detects whether a loop is formed due to the off-hook of the analog telephone 32. Loop presence / absence information indicating whether or not a loop has been formed is supplied to the telephone status code circuit 39 by the operation of the contact det by the relay DET. The telephone status code circuit 39 receives the supplied loop presence / absence information in the receiving circuit 63 and stores it in the register 64. The register 64 writes the loop status code 54 in the status code area of the packet signal in accordance with the stored leap presence / absence information, and supplies it to the ATM switch 31 via the connection line 42.

The voice signal supplied from the analog telephone 32 is converted into a packet signal by the packet signal unit 66 and supplied to the ATM switch 31 through the connection line 36.

On the other hand, the packet signal supplied from the ATM switch 31 via the connection line 37 is stored in the register 67 of the telephone status code circuit 39, and the polarity status code 56 and the call status code 57 are changed from the status code described in the status code area. Taken out. When the extracted polarity state code 56 is supplied to the drive circuit 68, the relay REV of the telephone state detection circuit 38 is driven according to the state. That is, the contact point rev is switched by the polarity state code supplied to the relay REV, and the normal power supply for supplying the current from the power supply circuit 61 to the analog telephone 32 in a state where the analog telephone 32 does not drive the relay REV according to the call state. And the analog telephone 32 with the relay REV activated
Is switched to reversal power supply for supplying current from the power supply circuit 61 to the power supply circuit 61. When the ringing code 57 is supplied to the drive circuit 68, the relay RING of the telephone state detection circuit 38 is driven according to the state. That is, when the analog telephone 32 receives an incoming call, the relay RING is driven, the contact ring is connected, and a call signal is transmitted.

The voice packet signal supplied from the ATM switch 31 is supplied from the connection line 37 to the packet signal unit 66, converted into an analog signal, and supplied to the analog telephone 32.

FIG. 4 shows details of the circuit switch adapter 41 and the circuit switch 33. The circuit switch adapter 41 is
The packet signal supplied from the ATM switch 31 via the connection line 42 is stored in the register 71, and the reap status code 54 described in the status code area is extracted. When the extracted loop state code 54 is supplied to the drive circuit 72, it drives the relay L of the circuit switch state detection circuit 46 according to the state. When the relay L is driven, the contact l is connected, and a loop is formed between the relay L and the subscriber circuit 44 of the circuit switch 33.

The subscriber circuit 44 of the circuit switch 33 has a relay DET for detecting the presence or absence of a loop at the end of the subscriber line. The relay DET detects the presence / absence of a loop formed with the circuit switch status detection circuit 46, and uses the contact det to detect the presence or absence of a loop.
The detection result is notified to a processing unit (not shown) in (3).

On the other hand, the relay REV and the relay RING in the circuit switch adapter 41 are relays that operate according to control information from a processing device (not shown) of the circuit switch 32. The contacts of these relays
By the disconnection of rev and ring, control of normal power supply and reversal power supply to the analog telephone and control of transmission of a call signal are performed, respectively. Relays R and N and relay D in the circuit switch adapter 41 are relays for detecting the states of the power supply circuit and the call circuit of the subscriber circuit 44 on the circuit switch 33 side, respectively. Relays R and N are relays for detecting reversals and normal polarity, and relay D is a relay for detecting a call signal. When these relays R and N and relay D are driven, respective contacts r and n and contact d are disconnected according to the state. The contact information of the contacts r, n, and d is supplied to the status code conversion circuit 74 of the circuit switch status code circuit 47. In the state code conversion circuit 74, the contacts r, n
Is converted to a polarity state code 56, and the contact information due to disconnection of the contact d is converted to a call state code 57. Each state code 56 converted by the state code conversion circuit 74,
57 is stored in the register 76 and the ATM switch 3
Supplied to 1.

The voice signal supplied from the circuit switch 33 is converted into a packet signal by a packet signal unit 78, and the ATM switch 3
Supplied to 1. On the other hand, the voice packet signal supplied from the ATM switch 31 is supplied from the connection line 42 to the packet signal unit 78, converted into an analog signal, and supplied to the circuit switch 33.

〔The invention's effect〕

According to the present invention as described above, an ATM switch,
Since the analog telephone and the circuit switch are connected by the terminal adapter for the analog telephone and the adapter for the circuit switch, it is possible to connect the ATM switch to the existing circuit switch.

Further, by removing the analog telephone terminal adapter, all the analog telephones accommodated in the packet switching device can be changed to the telephones of the packet terminals. Also, by removing the adapter for the circuit switch, the circuit switch connected to the packet
Can be changed to an ATM switch. Therefore, it becomes possible to introduce the ATM switch step by step without wasting the circuit switch which currently accounts for the majority and the analog telephones accommodated therein.

[Brief description of the drawings]

1 to 4 are diagrams for explaining an embodiment of the present invention, in which FIG. 1 is a block diagram showing a configuration of a packet switching device, FIG. 2 is a configuration diagram of a packet signal, FIG. 3 is a block diagram showing a configuration of a terminal adapter for an analog telephone, FIG. 4 is a block diagram showing a configuration of a circuit switching interface adapter, FIG. 5 is a schematic configuration diagram of an ATM,
FIG. 6 is a circuit diagram for explaining the concept of the switch circuit of the switching connection device. 31… ATM switch, 33… Terminal adapter for analog telephone, 38… Phone state detection circuit, 39… Phone state detection circuit, 41… Circuit switch adapter, 46 …… Circuit switch state detection circuit, 47… ... Circuit switch status code circuit.

Claims (1)

(57) [Claims] 1. An ATM exchange for switching and connecting a packet signal according to its label information, an analog telephone, and a loop of the analog telephone in an information area of the packet signal, a polarity of a power supply circuit of a subscriber circuit of the circuit exchange, and First state code means for writing a state code representing each state between the analog telephone and the circuit switch, comprising the presence / absence of a call signal to the analog telephone in the subscriber's circuit, and supplying the state code to the ATM switch;
Identify the status code supplied from the TM exchange and control the loop of the analog telephone, the polarity of the power supply circuit of the subscriber's circuit of the circuit exchange, and the calling signal for the analog telephone at the subscriber's circuit to correspond to the state. A terminal adapter for an analog telephone having first state identification control means, connected to a subscriber circuit of a circuit switch, and identifying a state code from a packet signal supplied from the ATM switch so as to correspond to the state. Second state identification control means for controlling the state of the subscriber circuit, and second state code means for writing a state code corresponding to the state of the subscriber circuit into the information area of the packet signal and supplying the state code to the ATM exchange. A packet switching device comprising: a circuit switching adapter.