JPS61142832A - Transmission system of telephone signal - Google Patents

Abstract

PURPOSE:To improve the overall efficiency for transmission of telephone signals by switching the connection mode with addition of a specific bit pattern. CONSTITUTION:The dial pulses are led to a mode switch 10 and a dial pulse signal tone coder 20. The switch 10 sets a connection mode when the dial pulse signal is not active and transmits the dial pulse signal and the signal tone information through a multiplexer 40. Then the output of a voice coder 30 is transmitted in a call mode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a telephone signal transmission system for telephone terminal equipment applied to a telephone network using a digital communication channel.

[Prior art]

The PCM-24B system, which uses the PCM encoding system, is currently mainly used in Japan as a telephone network using digital communication channels. In this case, the dial pulse is created by removing information from the audio signal by one bit every six samples, and is sent accordingly. In other words, the transmission speed of the transmission line is 6
4 bits per second divided into 62-g k bits of audio and 62-g k bits of dial pulse.

Each is transmitted independently. However, recently, with the aim of reducing communication costs, CODECs of about 2.4 to 4.8 bits/second have appeared. These C0D
In EC, if the dial pulse is assigned 11 bits, the voice quality will be significantly degraded, so it seems that other means 2, such as a punctured word channel of a modem, are used for transmission.

In this way, in the audio COD EC with a focus time of 7 seconds on 2.4, although the audio signal achieves extremely high efficiency, the dial pulse signal cannot be made that slow (
In the case of a 20 pulse/second dial and pulse, the limit is 200 focus/second when considering waveform reproduction), so there was a drawback that the overall efficiency was not improved. This drawback, to varying degrees, remained a major problem as the amount of bits in Gurus became relatively large.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an overall efficient telephone signal transmission system by performing dial signal transmission and voice transmission, which are essential for configuring a dial network, over the same communication channel.

[Structure of the invention]

The telephone signal transmission system according to the present invention receives a frame signal consisting of a specific bit pattern followed by a dial pulse and signal tone information, and includes a first encoding means for encoding the dial pulse and signal tone information. , a second encoding means that receives audio information and encodes the audio information; a multi-blephr that receives the output of the first encoding means and the output of the second encoding means, respectively; mode switching means for receiving a bit quturn and deriving an output corresponding to either a connection mode or a call mode distinguished by the specific bit zeturn; the output of the mode switching means causes the multiplexer to The encoded dial pulse and either signal tone information or voice information are selected from the multiplexer and sent to the same transmission path.

Ru.

[Principle and operation of the invention] The present invention eliminates the need to transmit only a signal tone such as a busy tone or a ring tone while a dial pulse is being sent in a dial network, and nine calls are made. It was conceived by focusing on the fact that there is no need to send Dial/Zorus while the system is in use. When the above two states are named connection mode and call mode, since the two modes are exclusive, there is no need to independently allocate the amount of transmitted information. Therefore, the C0DE in bits/second is 2.4
Even with C, dial pulses can be transmitted without reducing the amount of voice information.

Switching between the two modes described above is performed at specific bit turns within the frame. For example, it may be possible to allocate a billeter exclusively for switching one bit.

In order to further prevent audio quality deterioration, 5 bits are everything.”
1", it does not affect the connection mode. Also, the mode switching of the terminal station depends on the mode of the other party (which can be determined by the bits and mother turn of the received frame) and the state of the dial pulse of the own station. It can be determined from

[Embodiments of the invention]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In this figure, the signal input from the dial base signal input terminal 100 is as follows.

Mode switch 10 and dial/base signal tone encoder 20
be guided by. The mode switch 10 sets the connection mode when the dial pulse signal is not active (the value for making a call is active).

Mode switching is performed so that the call mode is set when the device is active. The purpose of this mode switching is to
Second dial tJ? Since the data is to be transmitted using the e-connection mode l', it is sufficient if it is sufficiently faster than that speed. Rather, in order to prevent unnecessary mode switching, it is effective to perform delay control such that the connection mode remains for about 100 milliseconds even when the dial pulse signal becomes active.

The mode switching signal is guided to multiplexer 40.

In the connection mode, dial/zoom signals and signal tone information are sent to transmission line 500. Also.

In the call mode, the output of the voice encoder 30 is controlled to be transmitted. On the other side, the demultiplexer 7'
At step 50, it is first checked whether the received frame is in connection mode or call mode by looking at the bit pattern, and if it is in connection mode, the information of the frame is sent to the dial/signal tone decoder 60, and the dial iE pulse and signal tone are decrypt to In the talk mode, the frame is sent to the voice decoder 70 and at the same time the dial pulse signal is interpreted as active.

FIG. 2 shows an example of the frame structure of two modes output from the multiplexer 40 in terms of format. In this figure, (a) is a frame in connection mode, and (b) is a frame in call mode. In case (a), the first 4 bits are mode identification bits, and when these 4 bits are all 1'', it indicates the connection mode.Other bits are used for dial noise and signal tone. It is used to transmit information. In the call mode (b), the first 4 bits take a combination other than 6 all 1" and are used to transmit voice information. All bits other than 4 pits are audio information. If the length of the frame mentioned here is 48 bits and 20 milliseconds (that is, 2400 bits/second on the transmission path), the number of bits of audio information reduced to pass the diamond is 20 m5/4
Bit x upper = L bit. this is.

It's only 0.5 cents or 1 cent out of a total of 48 pits.

There is almost no audio deterioration.

The effect obtained with the above minimum sacrifice is 20 mSS Kuji 484 = 44 for dial pulse and signal tone.
The advantage is that it can use bits and achieve the same accuracy as the dial and pulse in the PCM-24B system.

For example, if it is assigned to a 27-bit I-i dial pulse, the same accuracy will be obtained, so 17 pits will remain as signal tones. This makes it possible to send periodic signal tones and improves the ease of use of the network.

FIG. 3 shows operational waveforms when connected to an actual telephone network in the embodiment of FIG. 1. (
(a) is a dial pulse signal, and (b) is an operation waveform showing mode switching. When a call is not in progress, the dial pulse signal is inactive. At this time, the mode becomes connection mode.

Inactive waveforms are transmitted as is. When a call is made, it becomes active and enters 2-call mode. The diamond pulse is sent at 10 to 20 A pulse seconds, but at that time it is in connection mode and a fine pulse waveform is transmitted.

Note that although Figure 2 shows an example of 4 pits to represent a specific bit/group, this means that any number of bits greater than or equal to 1 can essentially achieve the same effect, although there may be differences in efficiency. That is clear.

In the above embodiment, for convenience of explanation, it is assumed that the audio C0DECi is 2.4 bits, but it is obvious that the two-way system is applicable to any digital audio terminal station having a frame structure, regardless of the binotrate. Also.

When the speed reaches 16 bits/second or 9.6 bits/second, it is possible to easily fulfill this role by lowering the number of quantization bits of the speech encoder without creating a separate signal tone encoder.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a telephone signal transmission system using a frame consisting of a plurality of bits, a mode in which dial noggles and signal tone information are transmitted by specific bit numbers or turns within the frame is provided. By providing a switching means that separates the mode into the mode for transmitting voice and voice, it becomes possible to exclusively send one mode to the transmission line, which has a great effect on efficiently transmitting telephone signals to the same transmission line. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment according to the present invention;
FIG. 2 is a format showing an example of the structure of a frame on a transmission line in the embodiment, and FIG. 3 is a time chart for explaining the operation of the embodiment. In the figure, 10 is a mode switcher, 20 is a dial pulse signal tone encoder, and 30 is a voice encoder. 40 is a multiplexer, and 50 is a demultiplexer. 60 is a dial pulse signal tone decoder, 70 is an audio decoder, 80 is an adder, and 500 is a transmission line. Figure 1 Figure 2 (α) (b) - Figure 3

Claims (1)

[Claims] 1. Inputting a frame signal consisting of a specific bit pattern followed by dial pulse and signal tone information;
Of these, a first encoding means encodes the dial pulse and signal tone information, a second encoding means receives voice information and encodes the voice information, and a second encoder encodes the output of the first encoder and the signal tone information. a multiplexer receiving the outputs of the two coding means, respectively, and receiving a specific bit pattern of the frame signal, and deriving an output corresponding to either a connection mode or a call mode distinguished by the specific bit pattern. and a mode switching means for controlling the multiplexer by the output of the mode switching means, and selecting from the multiplexer the encoded dial pulse and either signal tone information or voice information and transmitting the same. A telephone signal transmission method characterized by transmitting signals over the Internet. 2. The telephone signal transmission system according to claim 1, wherein periodic information of the signal tone is included as the signal tone information in the frame.