KR20060075057A - Voip system having a function for checking a subscriber line situation and controlling method therefore - Google Patents

Abstract

The present invention transmits a loopback testing signal before transmitting / receiving a call signal to the external line in a VOIP system connected to a subscriber terminal through an external line, processes the looped external state testing signal, and transmits and receives a variable digital filter value. A voice processor for digitally filtering a call signal or performing voice compression, and analyzing a loopback external state test signal recovered through the codec unit, and then variably setting a digital filter value using the resultant value. Provides a VIP system with a subscriber line status checking function comprising a and a control method thereof.

As described above, the VOIP system checks the state of the connected external line when there is a telephone call from the subscriber and when there is an incoming call, and variably sets the digital filter value of the codec according to the analyzed value. Checking and reflecting the change in the environment of the connected external line before the call signal is transmitted and received, thus significantly improving the noise characteristics of the call signal.

Codec, VOIP System, External Line, Digital Filter, Noise, IP Network, Voice Processor

Description

VOIP system having a function for checking a subscriber line situation and controlling method therefore}

1 is an explanatory diagram for explaining a VOIP system having a conventional fixed digital filter value.

2 is an explanatory diagram illustrating a VOIP system of the present invention.

3 is a flowchart of the present invention.

Fig.4 (a)-(b) is explanatory drawing which shows an example of the mathematical modeling of the outer line by this invention.

<Detailed Description of Codes>

1: subscriber terminal 2: outside line

3: VOIP system 4: protection circuit

5: slick part 6: codec part

7: IP network 8: voice processor

The present invention relates to a VOIP system equipped with a subscriber line status checking function and a control method thereof. In particular, the VOIP system checks the status of the connected external line when there is a telephone call from a subscriber and when there is an incoming call. The present invention relates to a VOIP system equipped with a subscriber line state checking function which significantly improves the noise characteristics of a call signal because the digital filter value of the codec is variably set.

In general, as the industrial society develops, information communication systems are widely used to transfer data from one point to another desired more appropriately and quickly. Such communication systems are usually homogeneous or heterogeneous communication devices which are geographically dispersed. In most cases, information devices are connected to a network to enable sharing and communication of resources. In the network, a switch is usually used to exchange information converted into an electrical signal with a counterpart, and is divided into a subscriber transmission connecting a subscriber and an exchange and a transmission between stations connecting an exchange period.

In particular, the conventional exchange system as described above is usually equipped with a variety of additional devices to implement a variety of additional functions, such as VoIP (Voice over internet protocal) function, such VoIP is the core technology of Internet telephony through the PSTN network so far Providing the voice service that has been made to various services using the Internet Protocol (IP), that is, the voice is digitized and the delivery system is IP, thereby improving Internet telephony such as Internet fax, web call, integrated message processing as well as telephone. Service becomes possible. In addition, since the VoIP technology should be linked not only to the Internet but also to a private IP based network, a public switched telephone network (PSTN), or a complex network thereof, standardization of technology and protocols is important, and importantly, H has been developed by ITU-T. There are .323-based technologies, SIP-based technologies developed by the IETF, and Media Gateway Control (MEGACO) -based technologies developed jointly by ITU-T and IETF to lead the next-generation VoIP gateway market.

Then, referring to Figure 1 of the VOIP system provided in the conventional exchange as described above, to protect the VOIP system 72 from the surge or overvoltage introduced from the outer line 71 of the two-terminal network connected to the subscriber terminal 70 A slick portion 74 for supplying a call current or outputting a ring signal to the subscriber terminal 70 through the protection circuit portion 73, the outer line 71 passing through the protection circuit portion 73, and the slick portion 74 A codec unit 75 for digitally filtering the call signal via a fixed filter value or performing voice compression, and converts the voice PCM data compressed by the codec unit 75 into packet data to convert the packet signal into an IP network ( 76 to voice processor 77 for transmitting to or performing the reverse process.

 Here, the codec unit 75 includes a low pass filter and a high pass filter which perform band filtering with a fixed filter gain value.

Here, referring to the procedure for setting the filter gain value of the digital filter of the codec unit, the digital filter value of the codec unit 75 is calculated under the best conditions in the laboratory and the calculated digital filter value is applied to the VOIP system 72. Test using the following PCM-4 instruments. In addition, when the result of testing with the PCM-4 device is compared with the ITU-T standard and the SPEC is satisfied, the digital filter value of the state is fixed to the digital filter value of the actual codec unit 75.                         

On the other hand, looking at the operation of the conventional VOIP system as described above, for example, when the call signal is transmitted through the external line 71 in the subscriber terminal 70 through the protection circuit unit 73 of the VOIP system 72 slick unit It is inputted by 74. The slick unit 74 converts the call signal of the two-terminal network input from the subscriber station 70 into a four-terminal network and inputs the signal to the codec unit 75. Then, the codec unit 75 digitally filters the call signal input from the slick unit 74 with a fixed filter value, and then compresses the voice signal to output the voice signal to the voice processor 77. Therefore, the voice processor 77 converts the voice PCM data compressed by the codec unit 75 into packet data and transmits the packet data to the IP network 76, thereby executing a normal IP call.

However, since the conventional VOIP system does not have a function of checking the state of the outer line in the codec unit, the digital filter value in the codec is set to a fixed value irrespective of the actual state of the outer line. Since it is not reflected in the digital filter value, the external noise is frequently generated in the call signal, and the call quality of the call signal is also significantly degraded when the noise generated by the external ray continuously affects the VOIP system. There was a problem.

Accordingly, the present invention has been invented to solve the above-mentioned conventional problems, and it checks and reflects the environment change of the external line connected to the VOIP system before the call signal is transmitted and received, thereby significantly improving the noise characteristics of the call signal. It is an object of the present invention to provide a VOIP system having a subscriber line state checking function and a control method thereof.

Another object of the present invention is to check the state of the external line through the codec without the need to add a separate complex circuit configuration to check the external line to improve the noise of the call signal transmitted and received accordingly accordingly voice quality of the VOIP system The present invention provides a VOIP system having a subscriber line state checking function and a method of controlling the same.

The present invention for achieving the above object is in a VOIP system connected to the subscriber terminal via an external line, before transmitting and receiving the call signal to the external line transmits the loopback testing signal and then processes the loopbacked external state testing signal and variable The codec unit performs digital filtering or voice compression on a call signal transmitted / received by applying a digital filter value, and an external state test signal for loopback recovered through the codec unit is analyzed, and then the digital value of the codec unit is Provided is a VIP system with a subscriber line status checking function including a voice processor for varying filter values.

Another feature of the present invention is a signal input checking step of confirming whether the current terminal is in the hook-off state or an incoming call is input in the VOIP system, and as a result of checking during the signal input checking step, the current terminal is in the hook-off state or is incoming. When the call is input, the codec unit transmits the external status testing signal to the external line and reports the loopback testing signal to the voice processor, and analyzes the external testing signal recovered by the codec unit by the voice processor after the external testing step. Then, the variable digital filter value calculating step of calculating and outputting the digital filter value of the codec unit using the result value, and the variable digital filter value calculated by the voice processor after the variable digital filter value calculating step are newly added to the digital filter. And then through the applied digital filter Provided is a control method of a BIO system having a subscriber line state checking function comprising a digital filter value applying step of digitally filtering a received call signal.

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

As shown in FIG. 2, the apparatus of the present invention includes a protection circuit section 4 for protecting the VOIP system 3 from surges and overvoltages introduced from the external line 2 of the two-terminal network to which the subscriber terminal 1 is connected, and the protection. A slick unit 5 for supplying a call current or outputting a ring signal to the subscriber terminal 1 through the outer line 2 via the circuit unit 4, and to the outer line 2 via the slick unit 5; A codec unit 6 which transmits a loopback testing signal and processes the looped external state testing signal and applies a variable digital filter value to digitally filter and / or compress a call signal transmitted and received; Converts the voice PCM data compressed by (6) into packet data and transmits it to the IP network 7, or performs the reverse process, and analyzes the loopback external state testing signal recovered through the codec unit 6. And then the result is Voice processor 8 which variably sets the digital filter value of the codec unit 6.

Here, the codec unit 6 includes a low pass filter and a high pass filter for performing band filtering, and these digital filters perform a filtering operation according to the digital filter value that the voice processor 8 variably sets. .                     

On the other hand, the loopback external state testing signal executed by the codec unit 6 includes the talk current, leakage current (between TIP and earth, between RING and earth, between TIP and RING), and capacitance (TIP and earth) flowing through the outside air. , RING and ground), and external inflow current.

Next, a control method applied to the apparatus of the present invention as described above will be described.

The method of the present invention proceeds from the initial state S1 to the signal input checking step S2 as shown in FIG. 3 to check whether the current terminal is in the hook off state or an incoming call has been input. At this time, as a result of checking during the signal input checking step (S2), if the current terminal is in a hook-on state or an incoming call is not input, the current state ends and proceeds to the standby state. However, if the terminal is currently in the hook-off state or an incoming call is input as a result of checking during the signal input checking step S2, the codec unit transmits the external status testing signal to the outside line and loops back to the outside line testing step S3. Report the testing signal to the voice processor. After the external testing step S3, the process proceeds to the variable digital filter value calculating step S4. The voice processor analyzes the external testing signal collected by the codec unit, and then uses the resultant value to determine the digital filter value. Output the output. In addition, after the variable digital filter value calculating step S4, the digital filter value applying step S5 is performed to newly apply the variable digital filter value calculated by the voice processor to the digital filter and transmit and receive through the applied digital filter. Digitally filter the call signal.

In other words, the codec unit 6 of the VOIP system 3 of the present invention includes, for example, a hook-off signal from the subscriber station 1 by the outer line 2, the protection circuit unit 4, and the slick unit ( If detected through 5) transmits the loopback external status testing signal to the external line (2). Then, the external state testing signal flows to the actual external line 2 and loops back and is recovered to the codec unit 6.

At this time, the looping testing signal is a communication current flowing through the outside line, leakage current (between TIP and earth, between RING and earth, between TIP and RING), capacitance (between TIP and earth, between RING and earth), and external inflow current. And the like are inputted to the codec unit 6.

The codec unit 6 then outputs the recovered testing signal to the voice processor 8. Then, the voice processor 8 performs external modeling according to the external test output of the input testing signal as shown in (ab) of FIG. 4 and uses a digital filter value calculation algorithm by the external modeling. To calculate the value. The voice processor 8 also inputs the calculated digital filter value to the codec unit 6. Then, the codec unit 6 applies the new digital filter value input from the voice processor 8 to the built-in digital filters, and then transmits a digit tone signal to the subscriber station 1.

On the other hand, the voice processor 8 outputs a ring control signal to the codec unit 6 when an incoming signal is transmitted to the subscriber station 1 through the IP network 7. Then, the codec unit 6 transmits the loopback external state testing signal to the external line 2 before transmitting the ring signal. Then, the external state testing signal flows to the actual external line 2 and loops back and is recovered to the codec unit 6.

At this time, the looping testing signal is a communication current flowing through the outside line, leakage current (between TIP and earth, between RING and earth, between TIP and RING), capacitance (between TIP and earth, between RING and earth), and external inflow current. And the like are inputted to the codec unit 6.

The codec unit 6 then outputs the recovered testing signal to the voice processor 8. Then, the voice processor 8 performs external modeling according to the external test output of the input testing signal as shown in (ab) of FIG. 4 and uses a digital filter value calculation algorithm by the external modeling. To calculate the value. The voice processor 8 also inputs the calculated digital filter value to the codec unit 6. Then, the codec unit 6 applies a new digital filter value input from the voice processor 8 to the built-in digital filters, and then transmits a ring signal to the subscriber station 1.

As described above, according to the present invention, the VOIP system checks the state of the connected external line when there is a telephone call from the subscriber and when there is an incoming call, and variably sets the digital filter value of the codec according to the analyzed result. Checking and reflecting the change in the environment of the external line connected to the system before the call signal is transmitted and received has the advantage of significantly improving the noise characteristics of the call signal accordingly.

In addition, according to the present invention. It does not need to add extra complicated circuit configuration to check the outside line, so it checks the state of the outside line through the codec and improves the noise of the incoming and outgoing call signal, thus improving the voice quality of the VOIP system.

Claims (3)

In VOIP system that subscriber terminal is connected through external line, A codec that transmits a loopback testing signal before transmitting or receiving a call signal to the outside line, processes the loopbacked external state testing signal, and digitally filters or compresses a call signal transmitted and received by applying a variable digital filter value. And a voice processor for analyzing the loopback external state testing signal recovered through the codec unit and then variably setting the digital filter value of the codec unit by using the resultant value. VIOAP system. 2. The loopback external state testing signal executed by the codec unit includes: talk current, leakage current (between TIP and earth, between RING and earth, between TIP and RING), and capacitance (TIP and BIP system with subscriber line status checking function, including checking between ground, RING and ground), external inrush current. In the VOIP system, when the terminal is in the hook-off state or the incoming call is input, the signal input checking step confirms whether the terminal is in the hook-off state or the incoming call is input. An external testing step for transmitting a status testing signal to the outside line and reporting the loopback testing signal to the voice processor, and after analyzing the outside testing signal recovered by the codec unit after the outside testing step, use the result value. A variable digital filter value calculating step of calculating and outputting a digital filter value of the codec unit; and applying the variable digital filter value calculated by the voice processor to the digital filter after the variable digital filter value calculating step is applied to the digital filter. Digitize call signal sent and received through The subscriber line status checking function, characterized in that consisting of a digital filter value applying step of filtering comprising V method of controlling a five Bahia system.

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