KR100493588B1 - Apparatus and Method for Converting μ-law and A-law in Switch - Google Patents

Abstract

According to the present invention, when a serial voice signal of a first scheme is received, it is determined whether to convert a telephone scheme, and when it is determined that the telephone scheme is to be converted, a second scheme code value corresponding to the first scheme code value is extracted, By converting the serial speech signal of the first scheme to the serial speech signal of the second scheme using the extracted second scheme code value, since the u / A law conversion function is serially processed, the implementation is simple and digital. U / A law conversion is possible even if the simple exchange does not have a u / A law conversion part.

Description

Apparatus and Method for Converting μ-law and A-law in Switch}

The present invention relates to a serial voice signal On exchanges that perform / A law conversion / A law conversion method and apparatus.

The exchange detects the connection request coming from the incoming line of the switch network, selects the outgoing line, establishes the line between the incoming and outgoing lines, and forms a transfer path between two or more subjects who transmit and receive voice information and data information. Monitor, cut, and charge on-board status.

When the exchange is classified according to the format of the communication information, the voice format such as conversation is called the telephone exchange, the text format such as the full text is called the telegraph exchange, and the image information format is called the image exchange. In addition, information format suitable for machine processing, including telegraph exchange and image exchange, is called data exchange. On the other hand, if the subject of communication is heeded, it is classified into domestic public exchange, international exchange, premises exchange, and leased line exchange. The purpose of the exchange is to provide the means of information transfer and the efficient operation of the circuit.

1 is a diagram schematically showing a configuration of a conventional digital switchboard, and FIG. 2 is a diagram showing a structure of a digital voice channel on a conventional system highway.

Referring to FIG. 1, the digital simplified switch exchanges digital voice signals input from an external network connection unit 100 for connecting a trunk line, a system highway connection unit 140 for connection with a system highway, an external network or a highway inside the system. Memory 110, 150 for storing, in parallel -Law / A-law voice conversion, and the voice switching unit 120 for the call channel switching function, for transmitting parallel voice data to the external network connection 100 or the system highway connection 140 in the form of a serial signal The parallel converter 130 and 160 may include a counter 170 for designating a memory address for a parallel signal transmitted from the external network connection unit 100 or the system highway connection unit 140.

The voice switching unit 120 is for using the exchange in a different call method according to the country / A law conversion table 125 is built in.

remind / A law conversion table (125) -law voice code to A-law voice code or A-law voice code -law code value to be converted into a voice code.

Hereinafter, the operation of the digital simplified exchange configured as described above will be described.

The serial voice signal transmitted from the trunk line is converted into a parallel voice signal by the external network connection unit 100 and transmitted to the memory 110.

The memory 110 stores the transmitted parallel type voice signal and transmits the same to the voice switching unit 120. The voice switching unit 120 determines whether to change the communication method for the transmitted parallel voice signal. In this case, the voice signal is This is described as the -law method.

If it is determined that the call method is to be changed with respect to the voice signal as a result of the determination, the voice switching unit 120 is configured to Recall the A-law code value that corresponds to the -law code value. / A law to extract from the conversion table (125) -law converts speech codes to A-law speech codes.

Thereafter, the voice switching unit 120 transmits the converted A-law type voice code to the parallel / serial conversion unit 130. The parallel / serial converter 130 converts the parallel voice signal of the transmitted A-law type voice code into a serial signal and transmits the serial voice signal to the system highway access unit 140. The system highway access unit 140 transmits the transmitted serial type voice signal through the system highway.

The structure of the digital voice channel on the system highway is shown in FIG.

Referring to FIG. 2, one line has 32 voice signal channels, and each channel is used as a voice call path. That is, up to 32 calls can be supported simultaneously through one line.

Since the processing of the voice signal transmitted through the system highway is the reverse of the above process, a detailed description thereof will be omitted.

However, in the above conventional The implementation is complicated because the / A law conversion function is processed in parallel.

Also, in the exchange If there is no / A law conversion part The problem is that the / A law conversion itself is not possible.

Therefore, the object of the present invention / A law conversion function serially to digital simple exchange Even without the / A law conversion part On exchanges with A / A law conversion / A law to provide a conversion device and method.

According to an aspect of the present invention, in order to achieve the above objects, when a serial voice signal of the first method is received, it is determined whether to convert the call method, and if it is necessary to convert the call method to the first method code value, Extracting a corresponding second scheme code value, and converting the serial speech signal of the first scheme into a serial speech signal of a second scheme using the extracted second scheme code value; A / A law conversion method is provided.

The first method and the second method It is different from one of -law and A-law.

According to another aspect of the present invention, a memory for storing a parallel voice signal transmitted through an external network connection, a voice switching unit for switching the parallel voice signal stored in the memory, a parallel voice signal transmitted from the voice switching unit A parallel-to-serial converting unit for converting a serial voice signal to a serial voice signal, and determining whether or not to change the communication method with respect to the serial voice signal transmitted from the parallel-to-serial converting unit. A serial for extracting a second code value corresponding to the code value and converting the serial voice signal of the first scheme into a serial voice signal of the second scheme. / A law conversion unit, the serial And a system highway connection for transmitting a second type serial voice signal transmitted from a / A law converter through a system highway. A / A law conversion device is provided.

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

3 is a diagram schematically showing the configuration of a digital simplified exchange according to a preferred embodiment of the present invention.

Referring to FIG. 3, the digital simplified switch exchanges a digital voice signal input from an external network connection part 300 for connecting a trunk line, a system highway connection part 340 for connection with a system highway, an external network or a highway inside the system. Memory 310, 350 for storing, voice switching unit 320 having a call channel switching function, for converting a parallel voice signal into a serial voice signal for transmission to the external network connection unit 300 or the system highway connection unit 340 Counter unit 370 for designating a memory address for parallel voice signals transmitted from parallel to serial converters 330 and 360, external network connector 300, or system highway connector 340, in series Serial to perform the / A law conversion function / A law conversion unit 380 is included.

The serial The / A law converting unit 380 determines whether or not to change the communication method for the serial type voice signal transmitted through the parallel converting unit 330 or the system highway access unit 340. In this case, the voice signal is This is described as the -law method. If it is necessary to change the communication method with respect to the voice signal as a result of the determination, the serial / A law converting unit 380 is the transmission of the serial voice signal extract the A-law code value corresponding to the -law code value. -law type voice code is converted to A-law type voice code. Then the serial The / A law converter 380 transmits the converted a-law voice code to the system highway access unit 340 or the memory 350. The serial A detailed description of the operation of the / A law converter 380 is described with reference to FIGS. 4 and 5.

Hereinafter, the operation of the digital simplified exchange configured as described above will be described.

The serial voice signal transmitted from the trunk line is converted into a parallel voice signal by the external network connection unit 300 and transmitted to the memory 310.

The memory 310 stores the transmitted parallel voice signal and transmits the same to the voice switching unit 320. The voice switching unit 320 transmits the transmitted parallel type voice signal to the parallel / serial converter 330.

The parallel-to-serial converter 330 converts the transmitted parallel-type speech signal into a serial form and serially Transfer to the / A law conversion unit 380.

Then, the serial The / A law converting unit 380 determines whether or not to change the communication method for the transmitted serial voice signal. In this case, the voice signal is This is described as the -law method.

If it is necessary to change the call method with respect to the voice signal as a result of the determination, the serial / A law converting unit 380 is the transmission of the serial speech signal extract the A-law code value corresponding to the -law code value. -law type voice code is converted to A-law type voice code. Then the serial The / A law converter 380 transmits the converted A-law serial voice signal to the system highway connector 340.

The system highway access unit 340 transmits the transmitted serial type voice signal through a system highway.

According to another aspect of the present invention, since the processing of the voice signal transmitted through the system highway is the reverse of the above process, a detailed description thereof will be omitted.

4 illustrates a voice signal according to an embodiment of the present invention. The following figure shows how to convert / A law.

The exchange digitizes the incoming analog signal and compresses it into an 8-bit signal. At this time, the compressed signal is used by inverting only the even bits in the A-law method. In the -law method, all bits are inverted and used. Therefore, the A-law signal The even-numbered bits of the -law signal are identical and only the odd-numbered bits are opposite. In this case, the most significant bit is used as a signal bit and is not inverted.

4, the serial The / A law converter inverts only three odd bits of the input PCM signal. then, -law speech signal is converted to A-law speech signal and A-law speech signal is -law Can convert to speech signal.

For example, bit 7 is not inverted to a signal bit, and bit 5, bit 3, and bit 1 are inverted because they are odd bits. then, -law speech signal is converted to A-law speech signal and vice versa.

5 is a state diagram using a preferred embodiment of the present invention The following figure shows how to convert / A law.

Referring to FIG. 5, the transfer from each state to the next state is automatically made by an input clock. Initially, it waits for input of the frame sync signal, which is in the state 0, and is a synchronization signal. When the frame sync signal is input, it moves to the state of state 1, and state 1 transmits bit 7, so that the input bit is output as it is without conversion. Thereafter, the state 1 moves to the state 2, and the state 2 transmits the bit 6, so the input bit is output as it is. After that, state 2 moves to state 3, and state 3 transfers bit 5, thereby inverting the input bit and outputting the inverted bit. As above, state 4 outputs the input bits as they are, state 5 outputs the input bits by inverting them, state 6 outputs the input bits as they are, state 7 outputs the input bits by inverting them, and state 8 inputs them. Output the bits as they are. Then go back to state 1 and do the same for the next channel.

The present invention is not limited to the above embodiments, and many variations are possible by those skilled in the art within the spirit of the present invention.

As described above, according to the present invention, Simple implementation due to serial processing of the / A law conversion function. Even without the / A law conversion part On exchanges with A / A law conversion / A law conversion apparatus and method can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram schematically showing a configuration of a conventional digital simple exchange.

2 illustrates the structure of a digital voice channel on a conventional system highway.

Figure 3 is a schematic diagram showing the configuration of a digital simplified exchange according to an embodiment of the present invention.

4 illustrates a voice signal according to an embodiment of the present invention. A diagram showing the conversion method / A law.

5 is a state diagram using a preferred embodiment of the present invention A diagram showing the conversion method / A law.

<Explanation of symbols for the main parts of the drawings>

100, 300: external network connection 110, 150, 310, 350: memory

120, 320: voice switching unit 130, 160, 330, 360: parallel series conversion unit

140, 340: system highway connection 170, 370: counter

380 serial / A law converter

Claims (3)

Determining whether to convert a call type when a serial voice signal of a first type is received; Extracting a second method code value corresponding to the first method code value when the call method needs to be converted; and Converting the serial speech signal of the first scheme into a serial speech signal of a second scheme using the extracted second scheme code value In the exchanger comprising a How to convert / A law. The method of claim 1, The first method and the second method In an exchange characterized in that it is different from one of -law method and A-law method How to convert / A law. A memory for storing parallel voice signals transmitted through an external network connection unit; A voice switching unit for switching the parallel voice signal stored in the memory; A parallel to serial converter for converting the parallel voice signal transmitted from the voice switching unit into a serial voice signal; It is determined whether or not to change the call method with respect to the serial voice signal transmitted from the parallel-to-serial converter, and when the call method needs to be changed, a second code value corresponding to the first code value of the serial voice signal is extracted. Serial to convert the serial voice signal of the first scheme into the serial voice signal of the second scheme / A law conversion; and The serial System highway connection for transmitting a serial voice signal of a second type transmitted from a / A law converter through a system highway In the exchanger comprising a / A law converter.