JPS61136347A - Busy tone detecting system - Google Patents

Abstract

PURPOSE:To make an external detecting device unnecessary, and to simplify a system constituting apparatus by providing a busy tone detecting function on a packet switchboard itself. CONSTITUTION:When a data frame of a connecting mode sent out of a vocoder 4 through a telephone set 1 and a private branch exchange 2 is received by a packet switchboard 5, pitch information in the data frame is extracted by an extracting means 50. Also, whether this pitch information is a frequency component of a busy tone or a silent component is checked and counted by a detecting means 51. When one period of a voiced state of a busy tone and a silent state is received by an optional number of times, a call is cut off by an informing means 52 and also its fact is informed to a packet network 6. In this way, it is necessary to install externally a busy tone detecting device, therefore, a system constituting apparatus is simplified, and also the cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a busy tone detection method, and more particularly to a busy tone detection method for detecting a busy tone transmitted from a vocoder in a packet switch.

[Conventional technology]

FIG. 4 is a diagram showing an example of connecting a regular telephone to a conventional packet network.

In the figure, a private branch exchange (hereinafter referred to as PKNW) is connected from a packet network (hereinafter referred to as PKNW) 6 via a packet switch (hereinafter referred to as PKSW) 5'.
The operation will be explained below by taking as an example the case where a call is received to the general telephone 1 housed in the PBX 2.

If the general telephone 1 is busy at the time of this incoming call, a busy tone is sent back from the PBX 2 to the PKSW 5' via g:xf (hereinafter referred to as VCR) 4. VCR, 4 is the busy tone!
When it receives a message, it converts it into a connection mode data frame with a frequency component set as pitch information and sends it to the PKNW 6 via the PKSW 5', but it does not have a busy tone detection function. On the other hand, since the PKSW 5' does not monitor the busy tone, it cannot disconnect the call due to the incoming call being busy. Therefore, conventionally, the busy tone is detected and p K
A busy tone detection device (hereinafter referred to as BTD) 3 was provided to notify the S W s' of this fact and cause the call to be disconnected.

[Problem that the invention seeks to solve]

The above-mentioned conventional busy tone detection method has the drawback that the number of components of the packet switching system increases and the cost increases by attaching the PKSW5' compatible KBTD3 externally to the PBX2.

[Means for solving problems]

The busy tone detection method of the present invention includes, in a packet switch,
Extracting means for extracting pitch information in a data frame of a connection mode sent from a vocoder when the data frame is received; a detecting means for checking and counting frequency components and silent components of a busy sound; and a notification means for disconnecting the call and notifying the packet network of this fact when the call is detected.

〔Example〕

Next, the present invention will be explained with reference to FIGS. 81 to 3.

FIG. 1 is a block diagram showing an embodiment of the busy tone detection method of the present invention, FIG. 2 is a diagram showing an example of the configuration of an audio data frame, and FIG. 3 shows the busy tone detection procedure in FIG. 1. It is a flowchart.

In FIG. 1, the same components as in the conventional example are denoted by the same reference numerals as in FIG.
(shown in FIG. 4) and extracts pitch information from seven frames of audio data when receiving a connection mode audio data frame (shown in the second cause) sent from the VCR 5; , a detecting means 51 for checking and counting the frequency component of the busy tone and the silent component;
The PKSWS is provided with a notification means 52 for notifying the PKSWS.

Next, in Fig. 2, the pitch information in the audio data frame is expressed by the general formula pitch (frequency x 125μS)XI
O”-10, it contains frequency components, and since the busy sound is expressed by repeating the sound state and silence state of a certain specific frequency, the values of the frequency components and silence components and their durations Busy tone can be detected from

This busy tone detection procedure is shown in FIG. This task shall be performed when a connected mode data frame is received during normal packet switch processing. First, flow 30
Pitch information P is extracted from the seven frames of audio data received in step 1, and it is checked in step 70-302 whether or not this pitch information P is a frequency component of a busy tone. If it is not a busy tone, (N.

) 70-310, it is checked whether or not there is a silent component. On the other hand, if the call is due to a busy tone (indicated by YES), the number tan of consecutive receptions of a busy tone is checked in 70-303. t4fi) indicates that the silent state has changed to the busy tone state, and therefore the silent state has ended. Then, at 70-304, the next time is silence.
) For processing at the time of death, the number of consecutive silent component receptions tb of the silent state that has just ended is converted to the number of consecutive silent component receptions in the previous cycle i'
After copying to ba, 71:f-305 and 7! ff
When Mi acknowledges that a normal silent state and a normal busy tone active state have been received at -306, processing at the time of busy tone detection is performed at 70-307, and the process returns to normal packet switching equipment processing. Further, when the check of 70-303, 305.306 is 1NO', the number of continuous busy tone receptions is incremented at 71:l-308. On the other hand, if it is a silent component in flow 310, the silent component is detected in 71:l-311, to 317. In the procedural theory, the busy tone is active and the silent condition is 1.
The call is disconnected when the cycle is received an arbitrary number of times.

In FIG. 3, symbol P represents pitch information within the audio data frame, α1. α is the minimum and maximum value that can be considered as the busy sound frequency component, tan is the number of consecutive receptions of the busy sound frequency component frame, and t'. is the number of continuous receptions of busy sound frequency component frames in the previous cycle, β ward, β spirit are the minimum and maximum values that can be considered as silence components, tbfl is the number of consecutive receptions of silence component frames, and t'bs is the silence component in the previous cycle The number of consecutive frame receptions, "1*11111", indicates the minimum and maximum number of consecutive receptions that can be considered as a normal busy tone state, and abIznbl indicates the minimum and maximum number of consecutive receptions that can be considered as a normal silent state, respectively.

The above-mentioned busy tone detection procedure includes an extraction means 50 in the PKSWs.
．． Although this can be realized by providing hardware for the detection means 51 and the notification means 52, it is generally very easily executed by software.

〔Effect of the invention〕

As explained above, the present invention eliminates the need for an external detection device because the packet switch itself has a busy tone detection function, which not only simplifies system configuration equipment but also reduces costs. There is also the effect of

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the busy tone detection method of the present invention, FIG. 2 is a diagram showing an example of the configuration of an audio data frame, and FIG. 3 shows the busy tone detection procedure in FIG. 1. Flowchart FIG. 4 is a block diagram showing an example of connecting a regular telephone to a conventional packet switching network. 1... General telephone, 2... Private branch exchange (
PBX), 3...busy tone detection device (BTD),
4...Bo;-da (VCR), 5.5'...
・Bakey) Exchange (PKSW), 6...Packet network (PKNW), 50...Extraction means, 5
1...detection means, 52...notification means. 4 half times!

Claims (1)

[Claims] In the packet switching equipment, an extraction means for extracting pitch information in the data frame when receiving the data frame in the connection mode transmitted from the vocoder, and a detection means for checking and counting the frequency component of the busy tone and the silent component. A busy tone detection method characterized by comprising: a notification means for disconnecting a call when a busy tone is detected and notifying a packet network to that effect.