JPH06237238A - In channel signaling transmission method - Google Patents

Abstract

PURPOSE:To eliminate a click sound being offensive to the ear, and also, to prevent disconnection of a signal in the course of speech by squelching a decoded sound signal, when signaling is in busy state and an idle state on a transmitting side and a receiving side, respectively. CONSTITUTION:When a first synchronization frame is detected by a synchronization frame detecting part 41, a synchronization frame output line 46a is asserted. When the necessary number of synchronization frames goes in, a synchronization defining output line 46b is asserted. In this case, when a signaling detecting output line 47 of a signaling detecting part 43 of a receiving side is an idle state and a transmitting signaling line 45c contained in an internal signaling line of a transmitting side is in a busy state, a selector 42 selects the output line 46a, and outputs it to an output line 46c. A squelching part 72 inserts a squelching signal to a decoded sound signal of a decoded sound signal line 45a when the output line 46c is asserted, and eliminates immediately a click sound of a squelch 42 and a signal output line 48a when an in-channel signaling frame is received, and prevents disconnection of a signal in the course of speech.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-channel signaling transmission method for inserting and transmitting an in-channel signaling frame in a coded voice signal.

[0002]

2. Description of the Related Art FIG. 11 is a block diagram showing a voice compression apparatus using a conventional in-channel signaling transmission method. In the figure, 1 is an encoder for encoding an audio signal,
2 is a decoder for decoding the encoded voice signal, and 3
Generates an in-channel signaling frame and inserts it into the voice signal encoded by the encoder 1. In-channel signaling transmitter 4 detects signaling from the in-channel signaling frame inserted into the encoded voice signal. In-channel signaling receiver.
Reference numeral 5 is a sync signal circuit for supplying a sync signal to them.

Further, 6a is a code synchronization signal line for transmitting a synchronization signal supplied from the synchronization signal circuit 5 to the encoder 1 and the in-channel signaling transmitter 3, and 6b is also the decoder 2 and the in-channel signaling reception. It is a decoding synchronization signal line through which the synchronization signal supplied to the device 4 is transmitted. Reference numeral 7a is a voice signal line for transmitting encoded voice signals, 7b is a signaling line for transmitting signaling, and 7c is a control signal line for transmitting control signals.

FIG. 9 is an explanatory diagram showing a format of a signal transmitted on the voice signal line 7a in the present invention and the conventional in-channel signaling transmission method, and FIG. 10 is a format of the in-channel signaling frame thereof. FIG. In FIG. 9, 2
1 is an in-channel signaling frame inserted by the in-channel signaling transmitter 3, and 22a ...
Reference numeral 22d is an audio signal encoded by the encoder 1 and band-compressed. Further, in FIG. 10, 31 is a synchronization frame of the in-channel signaling frame, 32 is also a signaling frame, and this in-channel signaling frame 21 is a synchronization frame 3 of 1 frame.
1 and the n-frame structure of the m-frame signaling frame.

Next, the operation will be described. Normally, the in-channel signaling transmitter 3 sends the compressed audio signals 22a to 22d from the encoder 1 to the audio signal line.
Here, when a change in the signaling signal line 7b is detected,
The in-channel signaling transmitter 3 generates the in-channel signaling frame 21 shown in FIG. 10, inserts it as shown in FIG. 2 in place of the compressed audio signals 22a to 22d generated by the encoder 1, and outputs the audio signal. Send to line 7a. When the in-channel signaling receiver 4 detects the in-channel signaling frame 21 inserted in the voice signals 22a to 22d in this way, it detects signaling from the signaling frame 32 and outputs it to the signaling signal line 7b.

The in-channel signaling frame 21 is a voice signal 2 which has been band-compressed by about 10 bits conventionally.
2a to 22d are provided with a synchronization frame 31 composed of a code that is unlikely to appear, and a plurality of frames (l frame in the illustrated example) are continuously provided for the purpose of preventing erroneous detection. For the purpose of transmitting information even if there is any, a plurality of signaling frames 32 (m frames in the illustrated example) are continuously provided.

Note that, as a document in which a technique related to such a conventional in-channel signaling transmission method is described, there is, for example, JP-A-1-261941.

[0008]

Since the conventional in-channel signaling system is configured as described above, the in-channel signaling frame 21 has no correlation with the band-compressed voice signals 22a to 22d and can be decoded as it is. The function of squelching the decoded audio signals 22a to 22d when appearing as an audible click sound and detecting the in-channel signaling frame 21 must also receive at least 5 or more synchronization frames 31 to prevent erroneous detection. Instead, a click sound appears, which causes problems such as a change in signaling that the other party goes off-hook, and a difficulty during on-hook or idle retransmission.

The present invention has been made in order to solve the above problems, and provides an in-channel signaling system that effectively eliminates a click sound that is audible to the ear and does not cause disconnection of a signal during a call. With the goal.

[0010]

According to a first aspect of the present invention, there is provided an in-channel signaling transmission method, wherein a synchronization frame is detected at least once when signaling is in a busy state on a transmitting side and idle on a receiving side. In addition, the squelch of the decoded audio signal is performed.

Further, in the in-channel signaling transmission method according to the present invention, the function of idle retransmission (off-hook retransmission) is stopped when the signaling is busy on the receiving side and idle on the transmitting side. .

The in-channel signaling transmission method according to the third aspect of the present invention further performs busy retransmission (on-hook retransmission) when the signaling is idle on the receiving side and busy on the transmitting side.

The in-channel signaling transmission method according to the invention of claim 4 squelches the decoded audio signal using the decoded audio signal of one frame before.

Further, the in-channel signaling transmission method according to the invention of claim 5 is predetermined as the decoded voice signal of the preceding frame based on the level of the decoded voice signal of the preceding frame. The squelch signal is switched and the decoded audio signal is squelched.

Further, in the in-channel signaling transmission method according to the invention of claim 6, squelch is performed using the decoded voice signal of one frame before from the first detection of the synchronization frame to the detection of a predetermined number. Then, squelch is performed using a predetermined squelch signal.

Further, the in-channel signaling transmission method according to the invention of claim 7 is the in-channel signaling transmission method, when the level of the transmission voice signal changes beyond a predetermined boundary level when the reception signaling is in a busy state. The frame is inserted.

[0017]

According to the in-channel signaling transmission method of the invention described in claim 1, a call is made by squelching voice when the first synchronization frame is detected in a state where the transmission signaling is busy and the reception signaling is idle. This prevents generation of a click sound that occurs after the called party goes off-hook or after the called party goes off-hook or an in-channel signaling frame is inserted by idle retransmission.

Further, in the in-channel signaling transmission method according to the second aspect of the present invention, when the reception signaling is busy and the transmission signaling is idle, idle retransmission is stopped, so that a click sound due to the insertion of the in-channel signaling frame is generated. Prevent occurrence.

Further, in the in-channel signaling transmission method according to the present invention as set forth in claim 3, busy retransmission is performed in a state where the received signaling is idle and the transmission side signaling is busy, and at that time, a busy retransmission request is issued. By doing so, it is possible to prevent idle retransmission that occurs when the receiving signaling on the called side remains idle due to a transmission error, and prevent the generation of a click sound.

In the in-channel signaling transmission method according to the present invention, the decoded speech signal is squelched by using the speech signal one frame before, thereby mitigating unnaturalness during squelch. To do.

Further, in the in-channel signaling transmission method according to the invention of claim 5, squelch is performed by switching between the decoded voice signal of one frame before and the predetermined squelch signal based on the level of the voice signal. This reduces unnaturalness during squelch.

Further, in the in-channel signaling transmission method according to the present invention, when the first sync frame is detected, squelch is performed on the decoded voice signal one frame before, and a predetermined number of sync frames are detected. By squelching with a predetermined squelch signal, unnaturalness during squelch is mitigated.

Further, in the in-channel signaling transmission method according to the present invention, when the reception signaling is busy and the level exceeds the predetermined boundary level and the transmission voice signal changes, the in-channel signaling frame is inserted. By doing so, the unnaturalness at the time of squelch is alleviated.

[0024]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a voice compression apparatus using an in-channel signaling transmission method according to the present invention. In the figure, 1 is an encoder, 2 is a decoder, 5 is a sync signal circuit, 6a is a code sync signal line, 6b is a decode sync signal line, 7a is a voice signal line, 7b is a signaling line, and 7c is a control signal line. 11 and is the same as or equivalent to those of the related art denoted by the same reference numerals in FIG. 11, and detailed description thereof will be omitted. Reference numerals 11 and 12 are in-channel signaling transmitters and in-channel signaling receivers different from those denoted by reference numerals 3 or 4 in FIG. 11 in that they have a click sound preventing function. Reference numeral 13 is an internal signaling line for transmitting and receiving a signaling state between the in-channel signaling transmitter 11 and the in-channel signaling receiver 12.

FIG. 2 is a block diagram showing the configuration of the in-channel signaling receiver 12 in the embodiment of the invention described in claim 1. In the figure, reference numeral 41 is a sync frame detection unit for detecting the sync frame 31 in the in-channel signaling frame 21, and 42 is two types of detection of the sync frame detection unit 41 according to the signaling states of the transmission side and the reception side. It is a selector that selects one of the outputs. Reference numeral 43 denotes a signaling detector that detects the signaling state of the receiving side and sends it to the selector 42.
Reference numeral 4 denotes the sync frame detection unit 4 selected by the selector 42.
It is a squelch unit that squelches a decoded audio signal according to the detection output of 1.

Further, 45a is a decoded voice signal line for inputting the decoded voice signal from the decoder 2, 45b is a code voice signal line for inputting the received coded voice signal, and 45c is a transmission signaling line. It is a transmission signaling line included in the internal signaling line 13 indicating the state. Four
6a indicates that the sync frame detector 41 detects the first sync frame 3
1 is a sync frame output line for detecting and outputting 1, and 46b is a sync confirmation output line for detecting and outputting sync confirmation by the sync frame detecting unit which has detected the necessary number of "l" sync frames 31.
6c is a selector output line of which one is selectively output by the selector 42. Reference numeral 47 is a signaling detection output line for outputting the signaling state of the receiving side detected by the signaling detection unit 43, and 48a is the audio signal line 7a.
A voice output line for outputting the voice of the squelch unit 44 to the
Is a signal output line for outputting the signaling of the signaling detector 43 to the signaling signal line 7b.

Next, the operation will be described. In FIG. 4, the first synchronization frame 31
Is detected, the sync frame output line 46a is asserted, and when the required number of sync frames is "l", the sync confirmation output line 46b is asserted. The signaling detection output line 47 of the signaling detection unit 43 is in the idle state, and the transmission signaling line 45c included in the internal signaling line 13
Is busy, the selector 42 selects the synchronous frame output line 46a and outputs it to the selector output line 46c. When the selector output line 46c is asserted, the squelch unit 44 inserts the squelch signal into the decoded audio signal of the decoded audio signal line 45a, and immediately after the in-channel signaling frame 21 is received, the squelch 1 and the signal output line 48a are inserted. It works so as not to output the click sound.

If the signaling detection output line 47 and the transmission signaling line 45c are both busy,
The selector 42 selects the synchronization confirmation output line 46b, and the squelch unit 44 does not squelch until the selector output line 46c is asserted. That is, since the squelch does not occur until the synchronization is established, the pseudo synchronization, that is, the synchronization frame in which several frames are consecutive is not squelched. Here, the signaling detection output line 47 is idle, and the transmission signaling line 45 is
When c is busy, the called side is on-hook (calling), and when the signaling detection output line 47 and the transmission signaling line 45c are both busy, conversation is in progress.
Clicking sounds caused by off-hook or idle retransmission during a call are immediately squelched, and the conversation is not interrupted by pseudo synchronization during the conversation.

Example 2. FIG. 3 shows an in-channel signaling transmitter 1 according to an embodiment of the invention described in claim 2.
2 is a block diagram showing a configuration of No. 1. In the figure, reference numeral 51 is a signaling insertion unit that inserts the in-channel signaling frame 21 into the audio signals 22a to 22d to be transmitted. Reference numeral 52a is a signaling transmission request unit for requesting the insertion of the in-channel signaling frame 21 to the signaling insertion unit 51, and 52b is a stop of the idle retransmission request transmission function which is periodically performed by the signaling transmission request unit 52a. It is an idle retransmission control unit for controlling the.

Further, 53a is the audio signals 22a to 22a to be transmitted.
Coded voice signal line for inputting 22d from the encoder 1, 53b
Is a signal input line for inputting signaling from the signaling signal line 7b, and 54 is a reception signaling line included in the internal signaling line 13 indicating the state of reception signaling. Reference numeral 55 is a signaling request line for transmitting the request signal from the signaling transmission request unit 52a to the signaling insertion unit, and 56 outputs the audio signals 22a to 22d encoded into the audio signal 7a and the in-channel signaling frame 21 inserted therein. It is a compressed signal output line.

Next, the operation will be described. When the state of the signal input line 53b changes, the signaling retransmission request unit 52a sends an insertion request for the in-channel signaling frame 21 to the signaling request line 55. The signaling insertion unit 51 that has received it inserts the in-channel signaling frame 21 into the encoded audio signals 22a to 22d from the encoded audio signal line 53a, and the compressed signal output line 5
6 to the audio signal line 7a. On the other hand, when the signal input line 53b is in the idle state, the signaling transmission request unit 52a determines that the signaling request line 55 is set for a certain period of time, for example, every 16S even if the signal input line 53b is not changed.
Then, the signaling inserter 51 is requested to idle-retransmit. However, when the reception signaling line 54 is busy, the idle retransmission control unit 52b controls the idle retransmission function of the signaling transmission requesting unit 52a.

When the signal input line 53b is idle and the reception signaling line 54 is busy, a click sound due to the in-channel signaling frame 21 is prevented, and both the signal input line 53b and the reception signaling line 54 are idle. The state is no call set up,
The signaling state of the opposite station is always matched by the idle retransmission function of the signaling transmission request unit 52a.

Example 3. FIG. 4 shows an in-channel signaling transmitter 1 according to an embodiment of the invention described in claim 3.
2 is a block diagram showing the configuration of No. 1, and the corresponding portions are given the same reference numerals as those in FIG. In the figure, 6
1 indicates the signaling state of the signaling line 7b input from the signal input line 53b, and the internal signaling line 1
3 is a busy retransmission unit that performs busy retransmission based on the signaling state of the reception side input from the reception signaling line 54 included in No. 3, and 62 indicates the busy retransmission request from this busy retransmission unit 61 to the signaling insertion unit 51. It is a busy re-send request line to convey.

As described above, by providing the busy retransmission unit 61 and the busy retransmission request line 62, before the called side becomes idle due to a transmission error and starts idle retransmission, the busy retransmission unit 61 makes a busy request. By performing retransmission, it is possible to artificially prevent idle retransmission due to no call setup. In this embodiment, the busy retransmission time is 2S.
~ 4S.

Example 4. FIG. 5 shows an in-channel signaling receiver 1 according to an embodiment of the invention described in claim 4.
2 is a block diagram showing the configuration of FIG. 2, corresponding parts are assigned the same reference numerals as in FIG. 2, and description thereof is omitted. In the figure, 7
Reference numeral 1 is a reception PCM register that stores and holds the decoded audio signal of one frame before, and 72 is a reception PCM register 71 built-in, and the audio signal decoded using the audio signal held therein is This is a squelch portion different from that denoted by reference numeral 44 in FIG. 2 in that squelch is performed.

By thus providing the squelch portion 72 including the reception PCM register 71, the reception PCM register 7
By squelching with the signal of one frame before stored in 1, the sound becomes more natural even if the squelch state occurs when the ringback tone is heard. It should be noted that the reception PCM register 71 newly stores the decoded audio signal from the decoded audio signal line 45a while the selector output line 46c is asserted and the squelch unit 72 inserts the decoded audio signal one frame before. Instead, keep the data.

Example 5. FIG. 6 is a block diagram showing the configuration of the squelch portion in one embodiment of the invention described in claim 5, and the corresponding portions are denoted by the same reference numerals as those in FIG. 5 and their explanations are omitted. In the figure, reference numeral 81 is a squelch signal register in which a predetermined squelch signal is stored. 82 is a 1 held in the reception PCM register 71
Reference numeral 83 is a level comparator for comparing the level of the decoded audio signal before the frame with a reference level, and 83 is a comparison output line from which the comparison result of this level comparator is output. Reference numeral 84 represents the decoded audio signal of one frame before held in the reception PCM register 71 and the squelch signal register 81 according to the comparison result of the level comparator 82.
Is a squelch selector for squelching a decoded audio signal by selecting one of the squelch signals stored in.

The level comparator 82 compares the level of the decoded audio signal one frame before stored and held in the reception PCM register 71 with the reference level, and the comparison result is compared with the squelch selector 84 by the comparison output line 83. I am sending it to. Here, when the signaling detection output line 47 is in the idle state and the transmission signaling line 46c is in the busy state, the squelch selector 84 receives the reception PCM register 71 when the comparison result by the level comparator 82 is smaller than the reference level. The decoded audio signal of one frame before, which is held in, is selected and output, and when the reference level is higher, the squelch signal previously stored in the squelch signal register 81 is selected and output. Squelch by doing. Therefore, when the level is high, the sound is not muted, and when the level is low, the sound is muted, and a more natural sound can be obtained.

Example 6. FIG. 7 is a block diagram showing the configuration of the squelch portion in one embodiment of the invention described in claim 6, and is the comparison output line 83 from the level comparator 82 and the selector 4 input to the squelch selector 84.
6 only in that the selector output line 46c from 2 is replaced by the synchronous frame output line 46a and the synchronous confirmation output line 46b from the synchronous frame detector 41.
It is different from the squelch part.

When the sync frame detector 41 detects the sync frame 31 of the in-channel signaling frame 21, the sync frame output line 46a is asserted when the first sync frame 31 is detected. When the synchronous frame output line 46a is asserted, the squelch selector 84 selects and outputs the decoded audio signal of one frame before stored and held in the reception PCM register 71. After that, when the required number "1" of the synchronization frames 31 are detected by the synchronization frame detection unit 41, the synchronization confirmation output line 46b is asserted. When the synchronization confirmation output line 46b is asserted, the squelch selector 84 selects and outputs the squelch signal previously stored in the squelch signal register 81. In this way, in the case of squelch in pseudo synchronization, the original level is held and the sound is not muted until the synchronization is established, whereby a more natural sound can be obtained.

Example 7. FIG. 8 shows an in-channel signaling transmitter 1 according to an embodiment of the invention described in claim 7.
2 is a block diagram showing the configuration of FIG. 1, and corresponding portions are assigned the same reference numerals as those in FIG. 3 and their explanations are omitted. In the figure, 9
1a is a transmission level comparator for comparing the level of the transmission voice signal from the coded voice signal line 53a with a predetermined level, and 91b has this transmission level comparator 91a built-in so that the level of the transmission voice signal is below a predetermined boundary level. This is a signaling transmission requesting unit different from the one denoted by reference numeral 52a in FIG. 3 in that it requests the signaling inserting unit 51 to insert the in-channel signaling frame 21 when it changes beyond.

In this case, the signaling transmission request unit 91b
When the transmission level comparator 91a detects that the level of the transmission voice signal on the coded voice signal line 53a exceeds "0", that is, when the code of the transmission voice signal is changed, the signaling insertion request 51 is issued. Output to. If the functions described in the first, fourth, fifth and sixth embodiments are not provided, the in-channel signaling frame 21
Since the sync frame 31 is a code having a relatively small level fluctuation, it has an effect of minimizing the click sound. Also, since the voice is over 300 Hz, 1.67
Since the code always changes once every ms, the transmission delay can be ignored.

[0043]

As described above, according to the invention described in claim 1, when the signaling is busy on the transmitting side and idle on the receiving side, the synchronization frame is decoded when it is detected at least once. Since it is configured to squelch the audio signal, the click sound generated by the insertion of the in-channel signaling frame due to off-hook or idle retransmission is immediately squelched by the detection of the synchronization frame, and the conversation is not interrupted by pseudo synchronization. There is.

According to the second aspect of the invention, when the signaling is busy on the receiving side and idle on the transmitting side, the periodic idle retransmission is stopped, so that the in-channel signaling frame is It is possible to prevent the generation of a click sound due to the insertion of, and there is an effect that the signaling states of opposite stations can always be matched.

Further, according to the invention described in claim 3, when the signaling is idle on the receiving side and busy on the transmitting side, the busy retransmission is further performed. Busy retransmission is performed before the idle transmission starts in the idle state, and pseudo idle retransmission due to no call setup can be prevented, and click noise can be prevented. .

According to the invention described in claim 4, 1
Since it is configured to squelch the decoded audio signal using the decoded audio signal before the frame, it is possible to alleviate the unnaturalness at the time of squelch, and to obtain a more natural sound. There is.

According to the invention described in claim 5, 1
Based on the level of the decoded speech signal before the frame,
Since the decoded audio signal of the preceding frame and the predetermined squelch signal are switched to squelch the decoded audio signal, the sound is muted when the level is low, and is muted when the level is high. There is an effect that it can disappear and become a more natural sound.

According to the sixth aspect of the invention, squelch is performed using the decoded voice signal of one frame before from the first detection of the synchronization frame to the detection of the predetermined number, and thereafter, in advance. Since the squelch signal is used to perform squelch, the original level is held and the sound is not erased until the synchronization is established, and a more natural sound can be produced.

According to the seventh aspect of the invention, when the level of the transmission voice signal changes beyond a predetermined boundary level when the reception signaling is busy, the in-channel signaling frame is inserted. With this configuration, the click sound due to the insertion of the in-channel signaling frame is prevented, and it is possible to alleviate the unnaturalness at the time of squelch.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a voice compression apparatus using the in-channel signaling transmission method of the present invention.

FIG. 2 is a block diagram showing an in-channel signaling receiver in Embodiment 1 of the present invention.

FIG. 3 is a block diagram showing an in-channel signaling transmitter according to the second embodiment of the present invention.

FIG. 4 is a block diagram showing an in-channel signaling transmitter according to the third embodiment of the present invention.

FIG. 5 is a block diagram showing an in-channel signaling receiver in Embodiment 4 of the present invention.

FIG. 6 is a block diagram showing a squelch portion in Embodiment 5 of the present invention.

FIG. 7 is a block diagram showing a squelch portion in Embodiment 6 of the present invention.

FIG. 8 is a block diagram showing an in-channel signaling transmitter in Embodiment 7 of the present invention.

FIG. 9 is an explanatory diagram showing a format of a signal transmitted on a voice signal line in the present invention and the conventional in-channel signaling transmission method.

FIG. 10 is an explanatory diagram showing a format of an in-channel signaling frame inserted in the signal.

FIG. 11 is a block diagram showing a voice compression device using a conventional in-channel signaling transmission method.

[Explanation of symbols]

 21 in-channel signaling frame 22a to 22d audio signal 31 synchronization frame 32 signaling frame

Claims (7)

[Claims] 1. A coded voice signal includes a plurality of synchronization frames formed of codes that are unlikely to appear in the coded voice signal, and a plurality of signaling frames carrying signaling. In an in-channel signaling transmission method of inserting and transmitting an in-channel signaling frame, when the signaling on the transmitting side is in a busy state and the signaling on the receiving side is in an idle state, when the synchronization frame is detected one or more times, An in-channel signaling transmission method comprising squelching the decoded voice signal. 2. A coded voice signal is composed of a plurality of synchronization frames formed by a code that is unlikely to appear in the coded voice signal, and a plurality of signaling frames carrying signaling. In an in-channel signaling transmission method for inserting and transmitting an in-channel signaling frame, when the signaling on the receiving side is in a busy state and the signaling on the transmitting side is in an idle state, idle retransmission requested in a predetermined cycle is stopped. An in-channel signaling transmission method characterized by the above. 3. The signaling of the receiving side is idle and the signaling of the transmitting side is busy,
The in-channel signaling transmission method according to claim 2, wherein busy retransmission is performed. 4. The squelch of the decoded speech signal,
The in-channel signaling transmission method according to claim 1, wherein the decoding is performed using a decoded voice signal of one frame before. 5. The squelch of the decoded audio signal,
When the level of the decoded audio signal of one frame before is higher than the reference level, the decoded audio signal of the one frame before is used, and when it is small, a predetermined squelch signal is used. The in-channel signaling transmission method according to claim 1. 6. The squelch of the decoded speech signal,
Characteristic that the decoded audio signal of one frame before is used from the detection of the first synchronization frame to the detection of a predetermined number of synchronization frames, and thereafter the predetermined squelch signal is used. The in-channel signaling transmission method according to claim 1. 7. The encoded voice signal comprises a plurality of synchronization frames formed of codes that are unlikely to appear in the encoded voice signal, and a plurality of signaling frames carrying signaling. In an in-channel signaling transmission method for inserting and transmitting an in-channel signaling frame, when the signaling on the receiving side is busy and the level of a transmission voice signal changes beyond a predetermined boundary level, the in-channel signaling frame A method for transmitting in-channel signaling, which is characterized by inserting a channel.