JPH06121059A - Trunk device for conference telephone - Google Patents

Abstract

PURPOSE:To provide a conference telephone function by providing a special trunk for performing mixing in analog. CONSTITUTION:A subscriber device of a digital telephone system switching the input/output to outgoing/incoming highways by a highway interface part 3, and mutually converting digital signals and analog signals between the subscriber device and the highway interface part 3 by a codec 4 to connect the arbitrary number of subscribers to digital highways is provided with a trunk 8 for conference telephone. The connection to the digital highways is performed by plural switching parts 5 corresponding to the selection of subscribers, the digital signals and analog signals are mutually converted with the switching parts 5 by plural codecs 6, and the analog outputs of the respective codecs 6 are mixed and returned again by a voice processing part 7. Thus, the conference telephone function can be achieved among the plural subscribers connected to the subscriber devices.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trunk device for conference telephones, and more particularly, to a plurality of subscriber interface circuits connected to an internal digital highway for time-division multiplexing voice signals via a digital transmission line. The present invention relates to a conference telephone trunk device for realizing a conference telephone function in a digital telephone system which is connected to an external line concentrator and then connected to a public line network via a normal subscriber line.

In recent years, due to the development of ISDN, packet switching networks, etc., communication systems using dedicated lines for transmitting digital signals have made great progress, and along with this, the subscriber side while transmitting data. There is an increasing demand for digital telephone systems as described above, that is, system cordless telephones, digital PBXs, and the like, which can transmit voice through the same line without requiring special processing.

Since such a system is often used for business use, it is desired to be able to support services such as conference calls. In this case, in consideration of price and the like, it is desired that the conference call function can be added later as an option to the basic function.

[0004]

2. Description of the Related Art In a telephone system in which voice is converted into a digital signal and a call path is formed on a digital highway by a time-division switch, a conventional method for realizing a conference telephone function is a control unit in a device. However, a method is used in which the digital voices of the subscribers participating in the conference are collected, logical addition is performed, and the addition result information is distributed to the subscribers via the highway.

[0005]

As a voice coding system in a digital communication system, a high efficiency coding system such as ADPCM is usually used from the viewpoint of effective use of a communication channel. Therefore, the voice information of each subscriber cannot be directly logically calculated and added.
It must be added after converting to a linear PCM code. Furthermore, the serially transmitted data must be stored for each subscriber, processed in real time, and then returned to each subscriber. Therefore, a control unit having a considerably high-speed processing function is required. Becomes

Further, since the normal TDM control must be performed even during the voice processing for the conference call, a high performance digital signal processor (DSP).
Must be mounted separately from the central processing unit (CPU). Moreover, if the voice signals from all the subscribers are added as they are, all of their own voices will be returned, which makes them unusable as a conference call. Therefore, in the end, each subscriber has to perform an arithmetic operation, which results in a considerably large arithmetic circuit, which is unsuitable for a small-scale system due to a cost problem. Is.

The present invention is intended to solve such a problem of the prior art, and does not rely on the digital processing system as described above, but has a high-way input / output and voice codec similar to the subscriber interface. And a special trunk for analog mixing of voice signals is prepared, and a call path is formed between the subscriber and the trunk by the same procedure as when forming an extension call path between subscribers. It is an object of the present invention to provide a trunk device for a conference call that realizes a conference call function.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a digital highway consisting of a downlink highway 1 and an uplink highway 2 is switched between input / output for the downlink highway 1 and the uplink highway 2 to make an external call and an extension line. An arbitrary number of subscribers are connected by connecting the subscribers via a highway interface unit 3 that enables a call and a codec 4 that performs mutual conversion between digital signals and analog signals between the highway interface unit 3. In a subscriber unit of a digital telephone system capable of connecting to a digital highway, a plurality of switching units 5 for connecting to the digital highway according to a subscriber's selection, and a digital signal and an analog signal between the switching units 5. A plurality of codecs 6 that perform mutual conversion of By providing a conference telephone trunk 8 having a voice processing unit 7 for mixing the analog output of the codec 6 and sending it back to the codec 6 and connecting to the digital highway, a plurality of subscribers connected to the subscriber device can be connected. The feature is that the conference call function can be achieved.

Further, according to the present invention, the switching unit 5 has the same highway input / output format as the highway interface unit 3, and by switching the input / output to / from the downlink highway 1 and the uplink highway 2, a conference call from an outside line is made. It is characterized by making it possible to participate in.

In the present invention, the conference telephone trunk 8 is
A voice service unit 9 for supplying a specific voice signal is provided, and when a voice call is received from an outside line to a subscriber, the voice signal is inserted into a mixing signal to the subscriber in the voice processing unit 7 so that the voice call from the outside line during a conference call. It is characterized in that the incoming call can be notified.

[0011]

In the subscriber unit of the digital telephone system, the highway interface section 3 is provided for the digital highway consisting of the downlink highway 1 and the uplink highway 2.
By providing input / output switching for the downlink highway 1 and the uplink highway 2 to enable external and internal calls, and to provide a codec 4 for digital signals and analog signals with the highway interface unit 3. Since the subscribers are connected by performing mutual conversion with and, the arbitrary number of subscribers can be connected to the digital highway. In the subscriber unit of such a digital telephone system, the conference telephone trunk 8 connected to the digital highway is provided, and the plurality of switching units 5 connect to the digital highway according to the subscriber's selection, thereby making it possible to connect to the plurality of digital highways. The codec 6 performs mutual conversion between a digital signal and an analog signal with the corresponding switching section 5, and the voice processing section 7 performs a process of mixing the analog output of each codec 6 and sending it back to the codec 6. As a result, the conference call function can be achieved among a plurality of subscribers connected to the subscriber device.

At this time, since the switching unit 5 has the same highway input / output format as the highway interface unit 3 to switch the input / output to / from the downlink highway 1 and the uplink highway 2, the outside line also participates in the conference call. can do.

Further, a voice service unit 9 is provided in the conference telephone trunk 8 so that a specific voice signal can be supplied, and when the subscriber receives an incoming call from an outside line, the voice processing unit 7 makes a subscription. Since the specific voice signal is inserted from the voice service unit 9 to the mixing signal for the person, when a call is received from an outside line during the conference call, the notification can be given.

[0014]

FIG. 2 shows the configuration of a subscriber unit according to an embodiment of the present invention, which illustrates a subscriber station of a digital telephone system supporting a conference call, and 10 is a subscriber unit. is there. Reference numeral 11 is a public line network, 12 is a concentrator for terminating the public line and then time-division-multiplexing the communication path, and 13 is a digital transmission path. In subscriber unit 10, TDM control section 14 performs time-division control, 15 ₁ ~
15 _n is an interface unit, 16 _{1 to} 16 _n are telephones,
Reference numeral 17 is a downward highway, 18 is an upward highway, 19 is a terminator for terminating the highway, and 20 is a conference telephone trunk.

In FIG. 2, the interface units 15 ₁ ...
The reference numeral 15 _n is connected to the downlink highway 17 and the uplink highway 18, and forms an outside line and an extension communication path according to a channel allocation signal from the TDM control unit 14. Each interface unit can be freely inserted and removed from the device, and an optimum system can be configured according to the number of subscribers 1 to n accommodated. The concentrator 12 is a concentrator for terminating the public line from the public line network 11 and time-division multiplexing the communication path.
3 is connected to the downstream highway 17 and the upstream highway 18 in the subscriber unit. Conference phone trunk 2
0 is connected to the downlink highway 17 and the uplink highway 18 in the subscriber device 10 under exactly the same conditions as the interface units 15 ₁ to 15 _n .

FIG. 3 is a diagram showing an outline of a voice system in the interface section. 21 is a voice processing section, 22 is a subscriber line interface circuit, 23 is a two-wire (2W) subscriber line, and 24 is a telephone. Is. In the voice processing unit 21, 25 is a control unit for controlling signal processing in the voice processing unit 21, and 26 is a highway interface for switching input / output between the downlink highway 17 and the uplink highway 18, and the inside of the voice processing unit 21. , 27 is a codec for mutually converting a digital signal and an analog signal, and 28 is a timing section for supplying an operation timing signal to the codec 27.

A subscriber number is assigned to each of the interface units 15 ₁ to 15 _{n, and} when the subscriber number of its own device is called, the control unit 25 sends a command from the TDM control unit 14 via the downlink highway 17. Is received and a pulse is sent to the timing unit 28. In the timing unit 28,
Based on this, a timing signal corresponding to the time slot assigned to the own device is created and supplied to the codec 27, and the codec 27 generates digital signals of the downlink highway 17 and the uplink highway 18 in accordance with this timing signal. , Mutual conversion between analog output signal and analog input signal.

The highway interface 26 switches the input / output to / from the downlink highway 17 and the uplink highway 18 in each of the interface sections 15 ₁ to 15 _n to form an extension communication path when called by an extension line and an external line. It is for forming an outside line communication path when called by.

FIG. 4 shows an example of the configuration of a conference telephone trunk.
Which is done in each processing unit consisting of 4 channels.
It is shown in FIG. 3 with suffixes 1 to 4 respectively.
For the parts corresponding to each component, add (') to the same number
25 'is a control unit, 26' ₁'~ 26_Four’Switches
Part, 27₁'~ 27_Four'Is codec, 28' is Thailand
It is the ming section. 29 is analog audio for conference calls
It is a processing unit.

The conference telephone trunk 20 has a plurality of functions corresponding to the voice processing section surrounded by a dotted line in FIG. 3, and also has a subscriber line interface circuit 22.
Instead, it has an analog voice processing unit 29 for conference call. Each switching unit 2 in the conference phone trunk 20
6 ₁ 'to 26 _4' each have a subscriber number, TD
The M control unit 14 can handle the subscriber interface circuit 22 in exactly the same manner, and the number of switching units determines the number of subscribers who can participate in the conference call at one time.

FIG. 5 shows the analog voice processing unit for conference call.
It is an example of the configuration, and corresponds to FIG.
27 is an example of the case of_1A'~ 27_4A'Is that
Re cordic 27₁'~ 27_Four’Half of
Converts digital signals to analog signals and 2
7_1B'~ 27_4B’Is a Cordic 27₁’～ 2
7 _FourThe other half of the '
Conversion to a digital signal. 31₁₁~ 31_14,31_{twenty one}~ 31
_{twenty four,}31₃₁~ 31_34,31₄₁~ 31₄₄Constitutes a coupling circuit
Resistance, 32₁~ 32_FourIs an adder, 33₁~ 33_FourIs
An amplifier, 35 is a voice service unit, and 36 is an amplifier.

In FIG. 5, from the ascending highway 18
The digital signal is transferred to the half part 27 of each codec._1A'~ 27
_4AOther than excluding its own device during output converted to analog signal with ’
Coupling circuit consisting of resistor circuit and adder only for device output
Coupled via the amplifier 33 ₁~ 33_FourThrough each outfit
The other half of the 27_1B'~ 27_4B’Enter again
Convert it to a digital signal and return it to the down highway 17.
Allows each subscriber to add the voice of each other subscriber.
Can be received by receiving the conference call function.
it can. At this time, the voice of the own device returns to the own device and the conference
Only the voices other than your own device are used so as not to disturb the conversation
Are configured to be added.

FIG. 6 shows a highway frame format. Among the time slots in the downlink highway, TS1 to TS3 indicate time slots to subscribers 1 to 3, respectively, and TS4 indicates time slots from the outside line. Further, among the time slots in the upstream highway, TS1 'to TS3' indicate the time slots from the subscribers 1 to 3, and TS4 'indicates the time slot to the outside line. A control time slot is provided at the head of each of the downlink highway and the uplink highway.

Now, in the subscriber apparatus of FIG. 2, a case where three subscribers and one of the outside lines join to make a conference call will be described with reference to FIGS. 2 to 5.

First, each participant has a conference telephone trunk 2
Dial the subscriber number assigned to 0. The same applies when joining a conference call from an outside line. TDM control unit 1
4 receives this and gives a busy notification if the conference telephone trunk is in use, and if not in use, it uses the downlink highway control time slot shown in FIG. a person 1-3 assigns switching unit for example 26 ₁ of conferencing phone trunks with _', 26 _2', 26 ₃ ', the time slots TS1, TS2, TS3, respectively. Next, the time slot TS4 is assigned to the outside line and the switching unit 26 ₄ ′. At this time, a command is sent to the switching unit 26 ₄ ′ to switch the input / output to / from the highway. Switching unit 26 ₄ in charge of the external line 'is thereby, takes data from the downlink highway 17, will output the data to the upstream highway 18, it is possible to form a speech path between the external line. In addition, the part forming the communication path with the subscriber in the device takes in the data from the up highway 18,
Data is output to the down highway 17.

The half 27 _1A '~ 27 _4A' of codec in conferencing telephone trunk 20 receives the digital signal from the participants in the conference call in charge, in response to a timing signal from the timing unit 28 ', an analog Along with converting into a signal, the voices from participants other than the own device are mixed in each coupling circuit, and then converted into digital signals by the other half of the codec 27 _1B 'to 27 _4B '.
The time slot assigned according to the timing signal is put on and returned from the downlink highway 17 to each subscriber. As a result, each participant can talk with a plurality of people at the same time by listening to the voice converted into the analog signal through the telephone, and the conference call function is realized. At this time, the voice level is adjusted by the conference telephone trunk 2
This is performed by selecting the resistance value that constitutes the coupling circuit within 0.

In this case, when an external line is received by the subscriber 1 during the conference, the TDM control section 14 controls the downlink highway as in the case of allocating the time slot. The time slot is used to send a command to the voice service unit 35 in the conference telephone trunk 20 to the subscriber 1 to send a catch tone. When receiving this command, the voice service unit 35 goes through the path indicated by the dotted line in FIG.
_A catch sound is sent to the adder 32 ₁ via ₁₄ . As a result, a catch tone is heard from the earpiece of the subscriber 1, so that the subscriber can interrupt the conference call and receive the outside line.

FIG. 7 shows a concrete example of the configuration of the present invention.
The digital system cordless telephone
It shows the case of the system, and also corresponds to ISDN.
It 31 is a public network, 32 is a subscriber line, 33 is digital
PBX, 34 is an ISDN line, 35 is a digital
System base cordless telephone system base station
is doing. The base station 35 has a digital high
This digital highway has a ray 36
And a conference telephone trunk 37 of the present invention on
It Again 38₁~ 38_FourIs a radio station, 39₁~ 39_FourHaso
Radio station 38 respectively ₁~ 38_FourCordless telephones belonging to
It is a terminal.

In FIG. 7, the subscriber line 32 from the public network 31 is concentrated by the digital PBX 33 and IS
The base station 3 via the DN-compatible serial interface
5 is connected to a digital highway 36. The digital highway 36 is connected the radio station 38 ₁ to 38 _4, conference call trunk 37 is also positioned on the digital highway 36.

The subscriber in this system, is a cordless telephone terminal 39 ₁ to 39 _4, by forming a communication path between the conference call trunk 37, a conference call, including an outside line, the base station 35 It can be implemented in a closed form within.

[0031]

As described above, according to the present invention, special control and complicated signal processing are performed by adding a simple panel constituting a conference telephone trunk to the conventional system. Instead, it is possible to implement the conference call function in the subscriber device in the digital telephone system and join the conference call from an outside line.

Further, the panel of the conference telephone trunk can be constructed so that it can be freely detached from the highway, like a normal subscriber interface, and therefore, it is not mounted when it is not necessary. There is an advantage that it is easy to take measures such as mounting two or more panels and increasing the number of participants in the conference when the frequency of use is high, as well as mounting and using as needed.

Further, according to the present invention, it is easy to provide a service such as an incoming call notification during a conference call.

[Brief description of drawings]

FIG. 1 is a diagram showing a principle configuration of the present invention.

FIG. 2 is a diagram showing a configuration of a subscriber device according to an embodiment of the present invention.

FIG. 3 is a diagram showing an outline of a voice system in an interface unit.

FIG. 4 is a diagram showing a configuration example of a conference telephone trunk.

FIG. 5 is a diagram showing a configuration example of an analog voice processing unit for conference call.

FIG. 6 is a diagram showing a highway frame format.

FIG. 7 is a diagram showing a specific configuration example of the present invention.

[Explanation of symbols]

 1 Downward highway 2 Upward highway 3 Highway interface section 4 Cordic 5 Switching section 6 Cordic 7 Voice processing section 8 Conference telephone trunk 9 Voice service section

Claims (3)

[Claims] 1. An external line call and an extension line by switching the input and output to and from the digital highway consisting of a downlink highway (1) and an uplink highway (2). Highway interface (3) that enables communication
And an arbitrary number of subscribers to the digital highway by connecting the subscribers via a codec (4) that performs mutual conversion between a digital signal and an analog signal with the highway interface section (3). In a subscriber unit of a connectable digital telephone system, a digital signal and an analog signal are provided between a plurality of switching units (5) for connecting to the digital highway according to a subscriber's selection. A conference telephone trunk (a plurality of codecs (6) for performing mutual conversion with a signal, and a voice processing unit (7) for mixing the analog output of each codec (6) and sending back to the codec (6) again ( 8) is provided to connect to the digital highway, thereby connecting a plurality of subscriber devices connected to the digital highway. Conference call trunk apparatus being characterized in that to be able to achieve a conference call functionality between subscribers. 2. The switching unit (5) has the same highway input / output format as that of the highway interface unit (3), and has a downlink highway (1) and an uplink highway (2).
The trunk device for a conference phone according to claim 1, wherein it is possible to participate in the conference phone from an outside line by switching input and output to and from. 3. The conference telephone trunk (8) comprises a voice service section (9) for supplying a specific voice signal, and the voice processing section (7) when an incoming call is received from an outside line to a subscriber.
3. The conference call trunk device according to claim 1, wherein the incoming call from the outside line is notified during the conference call by inserting the voice signal into the mixing signal for the subscriber in.