JP3749793B2 - Exchange device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exchange apparatus capable of setting any one of two or more compression methods for digitizing an audio signal, for example.
[0002]
[Prior art]
Conventionally, there is a key telephone main device used as an exchange device in a key telephone system used in an office building or business office. And this key telephone main unit has a built-in interface unit unit that connects a plurality of external communication networks such as extension lines, public networks, dedicated lines, etc., and has a communication control function with telephone terminals connected to them. ing.
[0003]
FIG. 6 shows a specific configuration of the interface unit.
That is, signals coming from a plurality of extension lines or external communication networks are captured by an interface unit 11 having n interfaces (IF) (111 to 11n), and subjected to call establishment control or the like, and then transmitted to the codec unit 12. Supplied. The codec unit 12 includes n variable codecs 121 to 12n each capable of switching the data compression method between the Mu rule and the A rule, and the variable codec 121 corresponding to an output signal from any one of the interfaces 111 to 11n. To 12n to be converted into a digital signal and output to the PCM highway 2. The interface unit 11 and the codec unit 12 are each controlled by the sub-control unit 13. Further, the sub-control unit 13 exchanges control information with the data highway 3. The Mu rule and the A rule are different from each other in the number of bits used for data compression and the quantization process.
[0004]
Here, in the variable codecs 121 to 12n provided in the unit, the Mu rule used mainly in North America, Japan and the like as a compression method for digitizing an audio signal, and A used mainly in Europe. The two types of methods are used, and the two types of methods can be selected from the outside. Which compression method is used in each country is determined, and the entire system must be fixed to either method according to the destination method.
[0005]
Thus, conventionally, as a compression method fixing method, the Mu law / A law switching selection pins of the variable codecs 121 to 12n of the codec unit 12 are fixed to 5V, -5V, and 0V for each unit. That is, if the resistor 14a is mounted and the resistor 14b is not mounted and 5V is applied to the switching selection pins of the variable codecs 121 to 12n, the Mu rule is obtained, and the resistor 14a is not mounted and the resistor 14b is mounted to -5V or If 0V is applied, it becomes A rule.
[0006]
However, in the conventional key telephone main unit, it is determined whether the Mu rule or the A rule for each destination, and the voltage input to the variable codec Mu rule / A rule switching selection pin is changed for all codec units in the system. Therefore, the mounting positions of the resistors 14a and 14b must be changed manually, and there are two types of units, the Mu rule and the A rule, for each unit, and the types of units are doubled. Become. For this reason, the configuration of the key telephone main device becomes large or complicated, and the device itself becomes expensive.
[0007]
In addition, since the selection of the data compression method is responsible for the setting for each unit, the compression method of a unit may be inconsistent with the law determined by the destination, and this compression method In order to determine whether or not there is a contradiction, there is also a problem that the contradiction cannot be determined unless a call is actually made with the unit.
[0008]
[Problems to be solved by the invention]
As described above, in the key telephone main device, in order to change the data compression method, the mounting position of the resistor for each unit must be set by a human hand, and the compression method of a certain unit is the destination. If there is a contradiction with the laws that are determined on the ground, there is a problem that it is not possible to determine whether or not the unit is inconsistent unless a call is made to the unit.
[0009]
Therefore, an object of the present invention is to eliminate the need for manual setting for each unit when switching the data compression method, and to prevent data from being inconsistent between the units, and to provide unified data within the apparatus. An object of the present invention is to provide a highly reliable switching apparatus that can realize a compression method.
[0010]
[Means for Solving the Problems]
The present invention relates to an extension interface unit that accommodates a plurality of extensions and has a communication control function with telephone terminals connected to these extensions and a data compression control function for converting a signal coming from the telephone terminal side into a digital signal. External interface unit unit having a communication control function between the communication unit and the external communication network and a data compression control function for converting a signal arriving from the external communication network side into a digital signal, and an extension corresponding to a call setting request The present invention is intended for an exchange apparatus including an exchange control unit that exchanges between an interface unit unit and an external interface unit unit.
[0011]
In order to solve the above object, the exchange control unit changes the data compression method of each of the extension interface unit unit and the external interface unit unit to one of the first compression law and the second compression law, which have different data compression methods. Selection information necessary for switching setting is sent to the external interface unit and the extension interface unit via the data control line for transferring control information between the extension interface unit and the external interface unit. Selection information transmission means is provided, and each of the external interface unit and the extension interface unit extracts the selection information transmitted by the exchange control unit, and first compresses the data compression method in the own unit based on the selection information. Compression method switching system to switch to the law or the second compression law It is obtained so as to comprise means.
[0012]
According to this configuration, the selection required to switch and set the data compression method of each of the extension interface unit and the external interface unit to one of the first compression law and the second compression law that are different from each other. The information is notified from the exchange control unit to the extension interface unit unit and the external interface unit unit, and each of the extension interface unit unit and the external interface unit unit is based on the notified selection information. The data compression method can be switched and set to either the first compression law or the second compression law. That is, it is possible to provide the switching control function for switching the data compression method of each unit unit to the exchange control unit that performs overall control of each unit unit, and between the extension interface unit unit and the external interface unit unit. Since the selection information is notified to each unit using a data highway for exchanging control information, it is not necessary to provide a dedicated line separately.
[0013]
For this reason, there is no need to provide a dedicated circuit for switching and setting the data compression method for each unit unit, and the data compression method of each unit unit can be switched at once by the exchange control unit. When switching the compression method, it is not necessary to make manual settings for each unit. Furthermore, there is no conflicting setting between the units, and a unified data compression method can be realized in the device. It becomes possible to improve.
[0014]
Further, according to the present invention, as selection information, information indicating the first compression law or the second compression law is assigned to one bit in the control data transmitted / received to / from one interface unit section via the data highway. Yes. For this reason, it is possible to reduce the amount of data necessary for sending the selection information.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an embodiment of a key telephone system according to the present invention, and numeral 4 indicates a key telephone main device constituting the core of the system.
[0016]
The key telephone main device 4 includes an external line interface unit 41, an internal interface unit 42, a dedicated line interface unit 43, and a central control unit 44, which are a PCM (Pulse Code Modulation) highway 45 and a data highway. They are connected to each other through 46.
[0017]
The external line interface unit 41 includes an interface unit (IF) 411, a codec unit (CODEC) 412, and a sub control unit 413. Among these, the interface unit 411 is connected to the public network 5 via the subscriber line SL, and performs processing for establishing a call with the public network 5 and the like. The codec unit 412 converts the output of the interface unit 411 into a digital signal and outputs the digital signal to the PCM highway 45. Conversely, the codec unit 412 converts the digital signal arriving from the PCM highway 45 into an analog signal and sends it to the interface unit 411. The sub-control unit 413 executes control processing for the interface unit 411 and the codec unit 412. The sub control unit 413 exchanges control data with the central control unit unit 44 via the data highway 46.
[0018]
The extension interface unit unit 42 includes an interface unit (IF) 421, a codec unit (CODEC) 422, and a sub-control unit 423. Of these, an extension EL is accommodated in the interface unit 421, and an extension terminal 6 such as a digital key telephone is connected to the extension EL. That is, the interface unit 421 performs outgoing / incoming processing for the extension terminal 6. The interface unit 421 also accommodates a plurality of extensions other than the extension EL. The codec unit 422 and the sub-control unit 423 perform the same processing as the codec unit 412 and the sub-control unit 413, and thus description thereof is omitted.
[0019]
The dedicated line interface unit 43 includes an interface unit (IF) 421, a codec unit (CODEC) 422, and a sub-control unit 423. Among these, the interface unit 411 is connected to the dedicated line 7 and performs a process for establishing a call with the dedicated line 7. Since the codec unit 432 and the sub control unit 433 perform the same processing as the codec unit 412 and the sub control unit 413, the description thereof is omitted.
[0020]
The central control unit 44 includes a time switch unit 441, a data control unit 442, a CPU 443, a ROM 444, a busy signal detection unit 445, a PB signal detection unit 446, and a compression method switching unit 448. Among these, the time switch unit 441, the data control unit 442, the CPU 443, the ROM 444, and the compression method switching unit 448 are connected to each other via the control bus 447. Further, the busy signal detection unit 445 and the PB signal detection unit 446 are connected to the time switch unit 441, respectively.
[0021]
The time switch unit 441 exchanges channels of digital signals transmitted through the PCM highway 45 among the external line interface unit unit 41, the internal line interface unit unit 42, and the dedicated line interface unit unit 43 in accordance with instructions from the CPU 443. The data control unit 442 exchanges control data required for each unit unit control with the sub control units 413 to 433 of each unit unit 41 to 43 via the data highway 46 in accordance with an instruction from the CPU 443. Note that the CPU 443 performs control processing of each circuit based on the program and control data stored in the ROM 444.
[0022]
The busy signal detection unit 445 and the PB signal detection unit 446 are for receiving a busy signal and a PB signal from the outside line, respectively.
Next, a circuit configuration for switching and setting the data compression method to one of the Mu rule and the A rule in the central control unit 44 will be described. In this case, an example in which the CPU 443 and the compression method switching unit 448 are combined will be described.
[0023]
The compression method switching unit 448 includes an I / O controller 51, a D-type flip-flop (D-FF) circuit 52, and an inverting circuit 53. The CPU 443 assigns a bit for switching the Mu rule / A rule to the control data output to the D-FF circuit 52. The control data is output to the output port on the control bus 447 by the D-FF circuit 52 based on the chip select signal. Note that. This chip select signal is output by the I / O controller 51 in response to an instruction from the CPU 443.
[0024]
The control data output from the D-FF circuit 52 is a signal having the Mu rule at the H (high) level and the A rule at the L (low) level. When inverted by the inverting circuit 53, the control data is at the H level. At the L level, the Mu rule is established. This control data or inverted control data is selectively used depending on the controlled element.
[0025]
The control data output from the data compression switching unit 448 is given to the busy signal detection unit 445 and the PB signal detection unit 446 via the control bus 447 and the time switch unit 441, respectively. Thereafter, the busy signal detection unit 445 and the PB signal detection unit 446 extract bit information indicating the Mu rule or the A rule from the input control data, and based on the extracted information, determine the data compression method of the circuit itself. Switch to Law or Law A.
[0026]
Next, a configuration for controlling the compression method using the data highway 46 will be described with reference to FIG. FIG. 3 shows an example in which the data control unit 442 and the CPU 443 are combined.
[0027]
The data control unit 442 includes a dual port RAM 61 and a sub CPU 62. As shown in FIG. 4, the CPU 443 assigns a Mu-law / A-rule bit to one bit of the 11-byte control data format 71 transferred via the data highway 46 to one unit. The control data is stored in the dual port RAM 61. In this case, the control data indicates Mu law at the H level and A law at the L level in the Mu law / A law bit.
[0028]
The control data stored in the dual port RAM 61 is read by the sub CPU 62 and then transferred to the sub control unit of each interface unit through the data highway 46.
[0029]
According to the above configuration, 14 unit units can be controlled by one data highway 46.
Next, the configuration of each unit will be described with reference to FIG. In FIG. 5, the same parts as those in FIG.
[0030]
That is, the sub-control unit 13 takes in the control data sent from the central control unit 44 through the data highway 46, extracts the Mu-law / A-law bits from the taken-in control data, and determines whether the Mu-rule It is determined whether it is A rule. This determination result is output to the output port 81 as a control signal for each of the variable codecs 121 to 12n, and thereafter used for switching the Mu law / A law switching selection pin of each of the variable codecs 121 to 12n.
[0031]
As described above, according to the above-described embodiment, the data compression methods of the external line interface unit 41, the extension interface unit 42, and the dedicated line interface unit 43 are the Mu rule and the A rule, which have different data compression methods. Selection information necessary for switching to either one is sent from the central control unit 44 to each interface unit 41 to 43, and the sub-control units 413 and 413 of each interface unit 41 to 43, respectively. Based on the transmitted selection information, 423 and 433 can switch and set the data compression method of their own codec units 412, 422 and 432 to Mu rule or A rule. That is, it is possible to provide the central control unit 44 that performs overall control of the interface unit units 41 to 43 with the data compression switching function of the interface unit units 41 to 43, and the data highway 46. Since the selection information is notified to each of the interface unit units 41 to 43 by using, there is no need to provide a dedicated line separately.
[0032]
Therefore, the central control unit 44 sets the data compression methods of the own unit and each of the interface unit units 41 to 43 at once without providing a dedicated circuit for switching and setting the data compression method for each interface unit. Therefore, when switching the data compression method, it is not necessary to perform manual setting for each unit section, and moreover, the settings do not contradict each other, and the key telephone main device. The data compression method unified within 4 can be realized. The central control unit 44 can also switch the data compression method of the busy signal detection unit 445 and the PB signal detection unit 446 provided in its own unit.
[0033]
Further, in the above embodiment, as selection information for switching setting to the Mu rule or the A rule, the Mu rule is added to one bit in the control data transmitted / received via the data highway 46 to one interface unit unit. Alternatively, a bit indicating the A rule is assigned. For this reason, it is possible to reduce the amount of data necessary for sending the selection information.
[0034]
In the above embodiment, the CPU 443 in the central control unit 44 needs to know whether the system is suitable for the Mu rule or the A rule, but this information is input by the operator. May be notified to the CPU 443, or a monitoring circuit or the like may be provided to determine the data compression method.
In addition, the present invention can be variously modified and implemented without departing from the scope of the present invention.
[0035]
【The invention's effect】
As described above in detail, according to the present invention, the data compression method of the codec unit in each unit unit can be switched between the Mu rule or the A rule using the control processing of each unit unit by the exchange control unit. Yes. For this reason, when switching data compression methods, there is no need for manual setting for each unit, and there is no conflicting setting between units, realizing a unified data compression method within the device. This makes it possible to provide a highly reliable exchange device.
[Brief description of the drawings]
FIG. 1 is a circuit block diagram showing an embodiment of a button telephone system according to the present invention.
FIG. 2 is a circuit block diagram showing a configuration for switching and setting to Mu rule or A rule in the central control unit in the embodiment.
FIG. 3 is a circuit block diagram showing a configuration for controlling a compression method using a data highway in the embodiment;
FIG. 4 is a diagram showing a format of control data transferred on a data highway.
FIG. 5 is a circuit block diagram showing a configuration of each interface unit section in the embodiment.
FIG. 6 is a circuit block diagram showing a configuration of each conventional interface unit.
[Explanation of symbols]
4 ... button telephone main unit,
5 ... Public network,
6 ... Extension terminal,
7 ... leased line,
11 ... interface part,
12 ... Codec part,
13: Sub-control unit,
41 ... External line interface unit,
42 ... extension interface unit,
43 ... dedicated line interface unit,
44 ... Central control unit,
45 ... PCM Highway,
46 ... Data Highway,
411, 421, 431 ... interface section,
412, 422, 432... Codec section,
413, 423, 433 ... sub-control unit,
441 ... Time switch part,
442 ... Data control unit,
443 ... CPU,
444 ... ROM.

Claims (2)

An extension interface unit unit that accommodates a plurality of extensions and has a communication control function between telephone terminals connected to these extensions and a data compression control function that converts a signal coming from the telephone terminal side into a digital signal; External interface unit unit having a communication control function with an external communication network and a data compression control function for converting a signal coming from the external communication network side into a digital signal, the extension interface unit unit, and the external interface unit Are connected via a PCM highway for transmitting the digital signal and a data highway for exchanging control information between the extension interface unit and the external interface unit in response to a call setting request. Via the PCM highway In exchange apparatus and a replacement control section for channel exchange of feed is the digital signal,
The exchange control unit
Selection information necessary for setting the data compression method of each of the extension interface unit unit and the external interface unit unit to one of a first compression rule and a second compression rule having different data compression methods is selected from the data highway. Selection information sending means for sending to the external interface unit and the extension interface unit via
When a codec capable of selectively setting the data compression method to the first compression rule and the second compression rule is incorporated, the data compression method of the codec is determined based on the selection information. An internal compression method switching control means for switching control to the second compression law,
Each of the external interface unit and the extension interface unit is
An interface unit having a communication control function between a telephone terminal connected to each of the plurality of extensions or the external communication network;
Analog / digital conversion means for converting the output of the interface means into a digital signal using a codec that can be selectively set to the first compression law and the second compression law;
In-unit control means for controlling the interface means and the analog / digital conversion means,
Compression system switching control means for switching control of the data compression system of the codec to the first compression law or the second compression law based on the selection information extracted by the intra-unit control means. An exchange device characterized by. The selection information sending means assigns information indicating the first compression law or the second compression law to one bit in the control data exchanged via the data highway for one interface unit, 2. The exchange apparatus according to claim 1, wherein the exchange device is means for sending control data to an intra-unit control means of each unit section.

Images