JPH0255450A - Pb signal transmission method for telephone system - Google Patents

Abstract

PURPOSE:To reduce a click noise by sending a PB signal while increasing a resistance of a speech circuit when an operation interval of a dial button is shorter than a preset time measuring time. CONSTITUTION:When a dial button 6 is depressed, a PB signal generating circuit 5 sends a PB signal and brings a level of a mute signal MUTE to an L level simultaneously. A control circuit 7 receives it to bring the level of a mute signal MUTE' to an L level. As soon as a speech circuit 4 reaches a state, where its DC resistance is increased, the circuit 4 allows a PB signal from the PB signal generating circuit 5 to send a PB signal to telephone lines L1, L2 via a diode bridge 3. A click noise is generated in the speech circuit 4 through the change in the DC resistance. The control circuit 7 brings the mute signal MUTE' to an H level through the reception of a time count end signal CT.OUT, the DC resistance of the speech circuit 4 is decreased, that is, restored to the resistance during talking and the state is restored to the speech state. In this case, the DC resistance is changed to cause a click noise in the speech circuit 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a PB signal transmission method for a telephone device, and particularly to a PB signal transmission method for a telephone device.
The present invention relates to a method for reducing click noise when transmitting a signal.

(Prior Art) FIG. 2 is a block diagram showing an example of a PB signal sending circuit of a conventional telephone device, and FIG. 3 is a timing chart showing an example of its operation.

In the same figure, 1 is a handset, 2A and 2B are handsets 1
Hook switch that turns on when raised, 3 is telephone line L
1 is a diode bridge that rectifies the current of L2, and 4 is a communication circuit. 5 is a PB signal generation circuit, and when hook switches 2A and 2B are on (off hook), the telephone line LL is
When the dial button 6 is operated (pressed), the dial button 6 is operated (pressed), and while the dial button 6 is being pressed, a PB signal of a frequency specific to each dialed number, etc., and a PB signal from the voice communication circuit 4 are transmitted. A mute signal MUTE for switching to the response is generated and applied to the communication circuit 4. The mute signal MUTE remains at a low level during the period including the pressing of the dial button 6 and the subsequent predetermined minimum pause tm.
The communication circuit 4 corresponds to the PB signal during the "L" period.

During the period in which the PB signal generation circuit 5 sends out the PB multiplied signal, the current consumption of the circuit 5 increases and the voltage of the circuit 5 decreases, which adversely affects its stable operation. This effect is particularly large when the losses in the telephone lines LL and L2 are large. To deal with this, generally the mute signal MUTE is set to “L”.
A method is used in which the direct current resistance of the communication circuit 4 is increased during the period ``, thereby increasing the resistance of the communication circuit 4 during transmission of the PB double signal.

When the resistance is increased or decreased, a clicking sound is generated as shown in FIG. Figure 3 shows each operation when the dial button 6 is operated at normal speed, and shows the minimum pose t.
Since m is generally set to 50 to 100 m5, each operation of the dial button 6 produces two click sounds corresponding to its depression and release. That is, since the handset 1 is configured to allow confirmation of the PBB tone, this click sound can be heard.

(Problem to be Solved by the Invention) However, in the above-mentioned PBB signal transmission method, the click sound occurs frequently, which is unpleasant to the ears, and removing this sound by hardware requires a complicated circuit, resulting in a decrease in reliability. There was a problem that it led to an increase in costs.

An object of the present invention is to provide a PBB signal transmission method that reduces click noise by simple means.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a PBB number sending method for a telephone device in which a PB signal of a period corresponding to the operation period is generated every time a dial button is operated. A predetermined clock time is set that is longer than the normal button operation interval, and the clock starts every time it detects that the dial button has been operated, and the clock starts counting when the predetermined clock time elapses from the latest time measurement start. A PBB signal transmission method was adopted in which the communication circuit resistance was increased during the entire time measurement and the communication circuit was switched to output for the PB signal.

(Function) According to the present invention, when a dial button is operated, a PB multiplication signal is generated every time the dial button is operated, and time measurement is started every time the dial button is operated. When the normal operation interval is short, the time measurement does not end before the next operation, and the time measurement continues with the next operation, and when the dial button is finally operated, the time measurement continues. The time measurement ends when the predetermined time period has elapsed, and during the entire time measurement, the communication circuit resistance is increased and the communication circuit is switched to be used for the PB signal.

(Embodiment) FIG. 1 is a block diagram of a PBB signal sending circuit of a telephone device as an embodiment of the present invention, and FIG. 4 is a timing chart showing an example of the operation of the circuit of FIG. 1.

In FIG. 1, the same parts as in FIG. 2 are denoted by the same reference numerals, and hereinafter, the different parts will be mainly explained.

7 is a control circuit which receives the mute signal MUTE sent from the PBB signal generating circuit 5 and generates the mute signal MUTE'.
and sends it to the communication circuit 4.

Reference numeral 8 designates a timer circuit, which sets an operation interval that is longer than the operation interval when the dial button 6 is operated at a normal speed, for example, a clocking time of about 10100O, and each of the mute signals M and U T E At the time of rising, the control circuit 7
When the start signal 5TART is received from the start signal 5TART, timing is started, and when the next mute signal falls within the set clocking time, the clocking time is reset and timing is interrupted, and when the next rising edge occurs, the timing is restarted. Start timing. Then, when the above-mentioned predetermined time period has elapsed since the most recent start of time measurement, the time measurement is ended and a time measurement end signal CT is generated.

OUT is sent to the control circuit 7. The control circuit 7 is.

The mute signal MUTE' is set to L during the period from the time when the mute signal MUTE is first received at "L" until the timing end signals CT and OUT are received, and the communication circuit 4 is operated in the same manner as in the circuit shown in FIG. Thus, the DC resistance is increased during the period when the mute signal MUTE' is "L".

Next, the operation of the circuit shown in FIG. 1 will be explained.

First, at time t1, when the handset 1 is picked up and off-hook, the PB signal generation circuit 5 is transmitted from the telephone lines Ll and L2.
Powered by PB signal generation circuit 5 is hook switch 2
Off-hook is detected by the operation of B, and mute signal MU is sent.
Set TE to high level "H". Mute signal MUTE
When becomes "H", the mute signal MUTE' of the control circuit 7 becomes "H", and the telephone communication circuit 4 is activated to become ready for telephone communication.

Next, in order to send out a PB double signal, for example, when a button ■ by the dial button 6 is pressed at time t2, the PB signal generation circuit 5 detects the button information, sends out a PB double signal corresponding to the button, and mutes at the same time. Set the signal MUTE to "L".

In response to this, the control circuit 7 outputs the mute signal MUTE'.
The telephone circuit 4 accepts the PB double signal from the PB signal generating circuit 5 at the same time as the direct current resistance increases, and passes it through the diode bridge 3 to the telephone line LL.

Sends PB double signal to L2. Due to the change in the DC resistance, a click sound is generated in the communication circuit 4 at the time t2. When the button (2) is released at time t3, the PB double signal transmission is stopped, and at time t4 after the minimum pause tm (for example, 60 m5), the mute signal MUTE changes from "L" to "H". In response to this, the control circuit 7 sends out a start signal 5TART to start the timer circuit 8.

Next, when the button ■ is pressed at time t5 while the timer circuit 8 is not counting 10100O, the mute signal MU
TE changes from "H" to "L", the control circuit 7 resets the timer circuit 8, and the mute signal MUTE' remains at "L".

Next, when the button ■ is pressed at time t6, the PB double signal is sent out, and at time t7, the PB double signal sending ends, and at time t8, when 60 m5 has elapsed, the mute signal MUTE changes from "L" to "H". Timer circuit 8 is activated. When 10100O has elapsed since the start-up due to no button operation thereafter, the timer circuit 8 sends time-counting end signals CT and OUT to the control circuit 7 at time t9.

The control circuit 7 receives the time measurement end signals CT and OUT and sets the mute signal MUTE' to "H", and the DC resistance of the communication circuit 4 is restored to the reduced value, that is, the resistance value during communication, and the communication state is returned. When the dial button 6 is operated for the first time, the handset 1 generates a click sound in the communication circuit 5 due to the change in the DC resistance. A total of two click sounds are generated at time t9 when the click sound is generated.

In the circuit shown in Fig. 1, the operation interval of the dial button 6 is 10
If it is 100O or more, a click sound will be generated for each operation as in the conventional circuit, but if the caller remembers the dial number, the operation is often within 500m5, so There is little chance that a click sound will occur during each operation of the dial button 6.

In the above embodiment, a case has been described in which the control circuit 7 generates a new mute signal MUTE' using the mute signal MUTE shown in FIG. 4 generated by the PB signal generation circuit 5. If the circuit 5 is replaced by a central control unit (CPU) that also performs other controls such as programmable control to generate the PB double signal, the mute signal MUT is directly transmitted from the control unit.
E' may also be generated. In that case, add a timer function to measure approximately 10100O inside the control device, and when the measured time elapses after the PB double signal ends, the mute signal MUTE' changes from "H" to "L". You can configure it to do so.

(Effects of the Invention) As explained above, according to the present invention, if the operation interval of the dial button is shorter than the preset clock time, the PB double signal is sent out while the communication circuit resistance remains increased. By setting the clock time to an appropriate time that is longer than the normal operation interval, there are fewer chances of clicking sounds occurring while operating the dial button, and the discomfort caused by clicking sounds is reduced. Reduced. This can be implemented by adding a simple electronic circuit or a program, making it possible to provide a highly reliable telephone device at low cost.

[Brief explanation of the drawing]

Fig. 1 is a PB signal sending circuit diagram of a telephone device as an embodiment of the present invention, Fig. 2 is a PB signal sending circuit diagram of a conventional telephone device, and Fig. 3 is a timing chart showing the operation of the circuit of Fig. 2. , FIG. 4 is a timing chart showing the operation of the circuit of FIG. 1. DESCRIPTION OF SYMBOLS 1... Handset, 4... Call circuit, 5... PB signal generation circuit, 6... Dial button, 7... Control circuit,
8...Timer circuit. Patent Applicant Oki Electric Industry Co., Ltd. Agent Patent Attorney Yoshi 1) Takashi Sei

Claims (1)

[Claims] Each time a dial button is operated, the period P corresponding to the operation period is
In the PB signal transmission method of a telephone device that generates a B signal, a predetermined clocking time that is longer than the normal operation interval of the dial button is set, and timing is started every time it is detected that the dial button is operated, A telephone device characterized in that timekeeping is stopped when the predetermined time has elapsed from the start of the latest timekeeping, and the click sound when a dial button is pressed is reduced by increasing the communication circuit resistance during the entire timekeeping. PB signal sending method.