JP4255428B2 - Exchange and exchange call control method - Google Patents

Description

  The present invention relates to an exchange, and in particular, a switch circuit for switching a communication path between a plurality of connected terminals, and a plurality of DSPs (Digital Signal Processors) provided in the communication path for digitally processing call information between terminals. And a call control method for the exchange.

In the field of telephone services in recent years, digital exchanges that digitally process line exchange connections are used.
The digital exchange includes a switch circuit for switching the communication path between a plurality of connected terminals, and a plurality of DSPs (Digital Signal Processors) for digitally processing the communication information between the terminals. The data is quantized by the DSP and converted into a digital signal, which is sent to the receiver side in packets of a predetermined capacity.
The DSP is equipped with a memory that stores the digitally processed digital audio data for each packet, and the digital audio data stored in the memory is read by the CPU for each packet and transmitted to the receiver side. ing.

  In the exchange as described above, since the CPU sequentially reads out the digital audio data stored in the memory based on the processing of the DSP and transmits it to the receiver side, the load on the CPU increases. In particular, in the case of a system connected to a network such as the Internet, the operation rate may be high because the CPU performs network processing, and the line connected to the exchange is fully connected. If the CPU load increases due to data transfer or large amounts of data, the CPU processing cannot keep up, and the sound quality of the call may be degraded.

  An object of the present invention is to provide an exchange capable of reducing the burden on the CPU and maintaining high sound quality.

An exchange according to claim 1 of the present invention includes an input side switch circuit and an output side switch circuit for switching a speech path between a plurality of connected terminals, and call information from the transmission side via the input side switch circuit. each of the well as stored in the memory for each unit packets digital processing, a plurality of DSP to make a predetermined flag area in a packet already stored in the flag in the memory corresponding to each packet (digital Signal processor), for every predetermined time When a predetermined flag area in the DSP's memory is referenced and it is detected that a packet stored flag is raised , the packet corresponding to the flag area is read from the memory, and the receiving side passes through the output side switch. A call control unit for transmitting to the telephone.
In this case, the call control unit configured by the CPU refers to a predetermined flag area in the memory of each DSP every predetermined time, and executes a packet transmission process when a corresponding packet is accumulated. CPU burden can be reduced.

The switch according to claim 2 of the present invention is the switch according to claim 1, wherein the memory is a dual port RAM in which one port is controlled by the DSP and the other port is controlled by the call control unit.
In this case, it becomes easy for the CPU to refer to a predetermined flag area in the memory, and it is possible to easily detect whether or not the corresponding processed packet is accumulated in the memory by reading the data in the flag area.
According to a third aspect of the present invention, there is provided a call control method for an exchange comprising an input side switch circuit and an output side switch circuit for switching a call path between a plurality of connected terminals, and a call between terminals provided in the call path. A call control method for an exchange comprising a plurality of DSPs (Digital Signal Processors) for digitally processing information and a call control unit connected to each DSP, wherein each DSP transmits a message via the input side switch circuit. The call information from the side is digitally processed and accumulated in a memory for each unit packet, and a step of setting a packet stored flag in a predetermined flag area in the memory corresponding to each packet, and the call control unit It refers to the predetermined flag area in the DSP memory for each, when it is detected that the packet already stored flag is set, whether the memory packets corresponding to the flag area Reading and a step of sending to the receiving side via the output-side switch.

  In this case, the call control unit configured by the CPU refers to a predetermined flag area in the DSP memory every predetermined time, and executes a packet transmission process when the corresponding packet is accumulated. Can be reduced.

  According to the present invention, the digital audio data processed by the DSP is stored for each packet in the memory, and since the flag indicating that the packet has been stored is set in a predetermined flag area of the memory, the CPU By referring to the flag area of the memory every predetermined time, it is possible to easily know whether or not the corresponding packet has been stored, and it is possible to reduce the burden on the CPU and maintain high sound quality.

An exchange in which an embodiment of the present invention is adopted will be described with reference to the drawings.
<Network configuration>
An example of the network configuration to which the exchange is connected is shown in FIG.
For example, it is connected via a router 201 to a wide area network (WAN) 100 such as a virtual private network (IP-VPN) operated on the Internet or IP base. A first LAN 200, a second LAN 300 connected via a router 301, and a third LAN 400 connected via a router 401 are illustrated.

Various devices used on an IP basis can be connected in the LANs 200 to 400. Here, connection examples of devices capable of making a phone call using an IP phone are shown. For example, a first exchange 203 is connected to the LAN 200 via a switching hub 202, and an IP telephone terminal 204 connected to the first exchange 203 by extension is provided. In addition, an IP telephone terminal 303 is connected to the LAN 300 via a switching hub 302. Further, two exchanges 403 and 406 are connected to the LAN 400 via a switching hub 402. A telephone terminal 404 and a paging broadcasting device 405 including a paging amplifier and a speaker are connected to the exchange 403, and a telephone terminal 407 is connected to the exchange 406. The installation of equipment in the LAN can be selected according to usage conditions. For example, a computer telephony (CTI: Computer Telephony Integration) terminal that integrates functions such as a telephone and fax into a computer terminal is adopted. can do. The presence / absence of the switching hub, the number of connection stages, and the like can be arbitrarily set.
<Internal configuration of the exchange>
The internal configuration of the exchange will be described with reference to the drawings.

  The exchange 1 includes a plurality of input terminals 2-1, 2-2,... Connected to the transmission side of the telephone, and a plurality of output terminals 3-1, 3-2,. , And input terminals 2-1, 2-2, ... and output terminals 3-1, 3-2, ... The input side switch 4 for switching the connection between the terminals 2-1, 2-2... And the plurality of communication paths 6-1, 6-2. .. and an output terminal switch 5 for switching the connection between a plurality of output terminals 3-1, 3-2..., And input terminals 2-1, 2-2. .., 6-2..., And output terminals 3-1, 3-2... Are connected with a speech path control unit 10 that controls the input side switch 4 and the output side switch 5.

Each speech path 6-1, 6-2, ... has a DSP (Digital Signal Processor) 7- that quantizes analog audio signals and converts them into digital signals, or restores digital signals and converts them into audio signals 1, 7-2.
Further, a paging interface 9 for connecting to paging broadcasting equipment such as a paging amplifier 10 and a speaker 11 for local broadcasting is provided as necessary.
The input terminals 2-1, 2-2,... Receive the audio signals output from the telephone transmitters 12-1, 12-2. Send.

The output terminals 3-1, 3-2... Send audio signals output via the communication path and the output side switch 5 to the telephone receivers 13-1, 13-2. .
The outputs from the plurality of DSPs 7-1, 7-2, etc. are connected to the paging interface 9, so that paging broadcasting can be performed through the speaker 11 from the telephone connected to the input terminal.
The paging interface 9 is used to select a paging broadcast system when connected to a D / A conversion unit to which the outputs of the DSPs 7-1, 7-2,. Paging output switch.

In the paging interface 9, the digital signal transmitted from the DSPs 7-1, 7-2,...
The speech path control unit 10 controls the input side switch 4 and the output side switch 5 in response to a call from the telephone, thereby constructing a bidirectional speech path on the transmission side and the reception side of the telephone. When there is a paging request from the telephone, the paging corresponding to the call is controlled via the paging interface 9 by controlling the input side switch 4, DSP7-1, 7-2,. The communication path is configured so as to be output to broadcasting equipment.
<Call control>
An example of call control will be described with reference to FIG.

DSPs 7-1, 7-2... Provided in the exchange 1 quantize analog voice data from the transmission side into digital voice data, and store the memories 15-1, 15 in packet units of a predetermined capacity. Store in -2 ...
The memories 15-1, 15-2,... Can be composed of, for example, a dual port RAM, and one of the two ports is controlled by the DSP 7-1, 7-2,. Can be configured to be controlled.
As shown in FIG. 4, the memories 15-1, 15-2,... Of the DSPs 7-1, 7-2,. A data storage unit composed of a second bank 54 to store, a first flag area 51 for storing a first flag indicating that the first packet has been stored in the first bank 53, and a second flag 54 in the second bank 54 And a flag area composed of a second flag area 52 for storing a second flag indicating that the packet has already been stored.

DSP 7-1, 7-2,... Convert analog voice data transmitted from the transmission side into digital voice data digitally processed in time series, and generate packets corresponding to predetermined capacity, respectively. The generated packets are stored in an area in the first bank 53 and the second bank 54 in the data storage units of the memories 15-1, 15-2,. DSP 7-1, 7-2,... Store the generated packets alternately in either the first bank 53 or the second bank 54.
When the packets are stored in the memories 15-1, 15-2,..., The DSPs 7-1, 7-2,.

The data storage units in the memories 15-1, 15-2, etc. can be configured to store two or more packets, and the number of flag areas is also supported based on the number of banks storing packets. To be configured.
The CPU 30 accesses the memory 15-1, 15-2,... Of each DSP 7-1, 7-2,... Every predetermined time and refers to the flag area. For example, the interval at which the CPU 30 refers to the flag area of the memory 15-1, 15-2,... Can be a time interval corresponding to the packet transmission interval, and the packet transmission interval is 10 msec. Can be configured to read out the values of the flag areas of the memories 15-1, 15-2,... At intervals of 10 msec.

  When the CPU 30 refers to the flag area of the memory of the specific DSP and detects a flag indicating that the packet is already stored, the CPU 30 reads the packet from the bank of the corresponding data storage unit and transmits it to the receiver side. . For example, when the flag is set in the first flag area 51 among the read flag areas, the first packet stored in the first bank 53 is read and transmitted to the receiver side. When the CPU 30 reads a packet from the memory 15-1, 15-2,... Of the DSP 7-1, 7-2,..., The CPU 30 stores the read packet in the data storage unit in which the packet was stored. Reset the value of the corresponding flag area. For example, when the CPU 30 reads the first packet stored in the first bank 53, the value of the first flag area 51 corresponding to the first packet is reset. The operation of resetting the flag area of the memory 15-1, 15-2,... When the packet reading by the CPU 30 is completed may be performed on the DSP7-1, 7-2,. Is possible.

  In such an embodiment, even if the CPU 30 of the exchange 1 has a high operation rate due to network processing or other processing, packet transmission is possible regardless of processing requests from the DSPs 7-1, 7-2,. Is processed at regular time intervals, processing requests from the DSPs do not overlap, and processing including other network processing can be performed smoothly.

  In the present invention, since the packet transmission processing of the exchange is performed at regular time intervals, the burden on the CPU can be reduced and the call can be maintained with high sound quality.

It is explanatory drawing which shows an example of the network structure by which one Embodiment of this invention is employ | adopted. It is explanatory drawing which shows schematic structure of call transfer operation | movement. It is explanatory drawing which shows the telephone call control of an exchange. It is explanatory drawing which shows the memory structure of DSP.

Claims (3)

An input side switch circuit and an output side switch circuit for switching a speech path between a plurality of connected terminals;
The call information from the transmission side is digitally processed via the input side switch circuit and accumulated in the memory for each unit packet, and the flag stored in the packet is stored in a predetermined flag area in the memory corresponding to each packet. With multiple DSPs (Digital Signal Processors)
When a predetermined flag area in the memory of each DSP is referred to every predetermined time and it is detected that a packet stored flag is set, a packet corresponding to the flag area is read from the memory and A call control unit for transmitting to the receiving side via the output side switch .   2. The exchange according to claim 1, wherein the memory is a dual port RAM in which one port is controlled by a DSP and the other port is controlled by a call control unit. An input-side switch circuit and an output-side switch circuit for switching a speech path between a plurality of connected terminals, and a plurality of DSPs (Digital Signal Processors) provided in the speech path for digitally processing speech information between terminals A call control method for an exchange comprising a call control unit connected to each DSP ,
Each DSP digitally processes the call information from the transmission side via the input side switch circuit and stores it in the memory for each unit packet, and the packet is stored in a predetermined flag area in the memory corresponding to each packet. Raising a stored flag,
When the call control unit refers to a predetermined flag area in the DSP memory every predetermined time and detects that a packet stored flag is set, the packet corresponding to the flag area is Reading from the memory and transmitting to the receiver via the output switch ;
Call control method for an exchange including

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