JPS60226265A - Incoming and outgoing collision prevention system of interior equipment - Google Patents

Abstract

PURPOSE:To prevent a collision between outgoing and incoming by detecting a dial tone signal and an audible tone of the sound band such as speech and data through a band-pass filter. CONSTITUTION:When automatic origination is performed, a CPU8 places a connection detection relay 10 in the contact state according to an indication from a memory 9 to close the DC circuit of a circuit 11. Then, a dial tone sent from an exchange side is detected by the band-pass filter 13 and a circuit without being passed through the band-pass filter. If there happens to be an incoming call, a signal arriving from an input port 16 through the filter 13 and a signal arriving from an input port 20 without being passed through the filter are different from each other because there is an input containing a different frequency component such as the speech signal. Therefore, the CPU8 detects the outgoing and incoming collision, and then interrupts originating and starts terminating.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a system for preventing collisions between calls and incoming calls for in-house equipment that has a means for connecting to a private branch exchange facility and a means for automatically transmitting text, voice, etc. be.

(Prior art) When automatically transmitting a selection signal to a public corporation's line in order to control the connection operation of switching equipment such as subscriber telephones, the transmission of the selection signal is started at least 3 seconds after the DC circuit is closed. The selection signal must be started to be sent after confirming the dial tone. Conventionally, when making an automatic call, most of the time the call is connected to a public corporation's switching equipment via a line, so polarity reversal detection is used to prevent collisions between incoming and outgoing calls.

This utilizes the fact that when a call arrives at your location, the polarity of the switched line in the standby state is reversed, and it detects whether or not there is a polarity reversal during the 3-second period, and if there is no polarity reversal, the call is received. This method determines that there is no call and starts transmitting a selection signal. However, many private branch exchanges and residential equipment do not perform this polarity reversal, so when making an automatic call from a residential equipment connected to a private branch exchange, the other party is connected to a public company line. , even if they are connected to the same private branch exchange, there is no effective way to prevent calls from colliding with each other, so this has to be done manually. Furthermore, when trying to automatically send data to Mr. A, if by chance there is a call from Mr. 8, a problem occurs in which the data addressed to Mr. A is sent to Mr. 8.

(Object of the invention) The present invention eliminates the conventional drawbacks as described above.
The purpose of this invention is to provide a method that prevents collisions between incoming and outgoing calls and allows a selection signal to be sent when making automatic calls.

(Structure of the Invention) For the above purpose, the present invention does not use polarity reversal, but uses a given audible sound signal to block the DC circuit, and then converts the audible sound signal and voice, data, etc. A selection signal is sent when the detection result of the auditory sound changes in the same period.

(Example) An embodiment of the present invention will be explained below with reference to the drawings.

Figure 1 shows a given audible sound signal after a home device connected to a private branch exchange goes off-hook, connects to a central office line (external line), sends out a selection signal, and calls the other party until the other party answers. FIG. As this audible sound signal, a central office line signal is used so that no matter which telephone is connected to the private branch exchange, there will be no mishearing. 400 Hz is generally used as this frequency. An example using this frequency will be described below, but the frequency is not limited to this.

If the in-home equipment that makes automatic calls is housed directly in the central office line, this continuous 400 Hz detection will cause
It is possible to confirm the dial tone, prevent collisions between incoming and outgoing calls, and send a selection signal. In the case of in-home equipment housed in a private branch exchange facility, it is necessary to detect the extension tone shown in Figure 1, but this signal tone depends on each private branch exchange facility. This signal tone interval,
Transmission frequencies are not standardized nationwide.

FIG. 2 is an example of a signal detection circuit for implementing the call collision method of the present invention. In the figure, 1 is an input terminal, 2 is a band filter that detects a 400 Hz signal,
3 is a 400 Hz signal output terminal, 4 is an amplifier for detecting the input level, 5 is an audio output terminal of the amplifier 4, 6 is an output example of the signal output terminal 3, and 7 is an output example of the audio output terminal 5. Therefore, when a 400 Hz signal or voice is input to the input terminal 1, the Pantone Yass filter 2
The amplifier 4 outputs only the Hz part to the signal output terminal 3, and the amplifier 4 outputs the part with a high input level to the audio output terminal 5.

Therefore, when changing to audio input after a 400 Hz signal input, the output 6,2 will be the original 40 Hz as shown in the figure.
In the case of intermittent signal input of 0 Hz, signals are outputted in the same format from both the output 6 and the output cuff, but when it comes to voice input, the two signals are detected asynchronously.

By comparing both signals, only the 400 Hz signal portion can be determined.

Therefore, if you go off-hook and there is a collision between incoming and outgoing calls, the other party's voice will be input, and if there is no incoming call, the other party's voice will be input.
An extension dial tone or a general dial tone is input. Therefore, by comparing the outputs of the signal output terminal 3 of FIG. 2 and the output of the audio output terminal 5 of the amplifier 4, it is possible to know whether there is a collision between outgoing and incoming calls.

The specific detection range of the pantono 4-sphere filter is as follows:
It's not that steep, and the mathematicians have no choice but to accept it. The main issue here is the extension dial tone, as mentioned above.
Although it cannot be limited to 400Hz, it is almost 400Hz.
The above objective can be achieved with a bandpass filter at Hz.

Next, an embodiment of the method of the present invention is shown in FIG.

When making an automatic call, the CPU 8 uses the program memory 9
According to the instructions, connect the connection detection relay 10 and connect the line 1.
Block the DC circuit No. 1. This line 11 is connected to a private branch exchange line or telephone line, and if the direct current circuit is blocked, the private branch exchange equipment or telephone exchange equipment sends out a dial tone when a call request is received. This dial tone is 400
The oscillation frequency is around 400 Hz, such as Hz alone or a combination of 350 Hz and 450 Hz, but the make/break period varies as described above.

This signal tone is passed through the bandpass filter 1 through the level adjustment circuit 12 corresponding to the bandpass filter 2 in FIG.
3, the rectifier circuit 14 and the level converter circuit 1
5, it is converted to TTL level and input port 1
The CPU 8 is notified via the CPU 6. Further, this signal tone is transmitted to the level adjustment circuit 17 corresponding to the amplifier 4 in FIG.
It is similarly detected by the rectifier circuit 18 and the level converter circuit 19 and is notified to the CPU 8 via the input port 20. When it is recognized that the signals notified from the input port 16 and the input port 20 are the same, the selection signal generation circuit 22 sends a selection signal to the line 11 via the output port 2. After waiting for a response from the other party, information can be exchanged with the other party via the input/output port 23 and the modulation/demodulation circuit 24. Hiko, the switch 25 does not disconnect the selection signal generation circuit 22 from the line 11 during communication;
This is for connecting to the modulation/demodulation circuit 24.

Therefore, when the DC circuit of the line 11 is blocked in order to make a call, if an incoming call happens to occur, there is an input with a different frequency component such as voice, so the input port that has passed through the bandpass filter 13 The notification from the input port 16 and the notification from the input port 20 that has not passed through the bandpass filter are different. In this case, it is assumed that there has been a collision between outgoing and incoming calls, and the automatic calling operation is stopped and incoming call operations, such as ringing a bell, are started.

(Effects of the Invention) As explained in detail above, the present invention is capable of preventing collisions between incoming and outgoing calls using audible sound signals, and has the advantage that automatic outgoing operations are possible regardless of the connection point of the in-home device. There is.

[Brief explanation of drawings]

FIG. 3 is a block diagram showing an embodiment of the incoming and outgoing call collision system of the present invention. 2... Pantone filter, 4... Amplifier, 8...
... CPU, 9... Program memory, 1o... Connection detection relay, 11... Line, 12... Level adjustment circuit, 13... Band pass filter, 14... Rectifier circuit, 15...・Level conversion circuit, 16... Input port, 17... Level adjustment circuit, 18... Rectifier circuit, 1
9... Level conversion circuit, 20... Input port, 21
...output port, 22, ...selection signal generation circuit, 23
...Input/output port, 24...Modulation/demodulation circuit Patent applicant Nippon Telegraph and Telephone Public Corporation Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In a call/receive collision prevention method for in-house equipment that has means that can be connected to private branch exchange equipment and means that automatically transmit text, voice, etc., there is It has means for detecting audible sounds in the voice band such as, means for transmitting a selection signal, and means for blocking a DC circuit for making a call, and after blocking the DC circuit,
A call collision method for in-house equipment, characterized in that a selection signal is sent when detection results of the audible sound signal and the audible sound change in the same cycle.