JPH11313131A - Telephone set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a telephone set capable of being applied to various kinds of TAs(terminal adapters) and normally terminating a call (sounding a ringer) while suppressing the generation of a resonance phenomenon. SOLUTION: In this telephone set, the voltage of a telephone line 1 is monitored in a level detection circuit 6, and when it is more than a threshold value set beforehand, detection signals are outputted to a ringer circuit 7 and the ringer circuit is provided with a function for operating a buzzer 8 and sounding the ringer. A changeover switch 11 linked with a line kind changeover switch 10 for switching a pulse line and a push line is provided. The changeover switch 11 is for changing the threshold value and is operated so as to lower the threshold value when the line kind changeover switch is a tone. In the case of the pulse line, since the threshold value is high, the resonance phenomenon is not generated by a principle similar to before. At the time of the tone, the threshold value is set to a voltage level lower than a normal threshold value, and even in the case that the voltage level of calling signals is low like the TA, the ringer is sounded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone.

[0002]

2. Description of the Related Art As is well known, a telephone (button type) has a built-in ringer circuit which detects a voltage (for example, 70 V) applied to the telephone at the time of an incoming call and sounds the ringer. . By the way, recently, a plurality of telephones are often connected in parallel to the same line, and the telephones are often used in a form of wired connection in a parent-child telephone format in which calls can be made and received from either telephone.

In this case, when the type of the connected line is a pulse line, if one of the telephones dials to make a call, a dial pulse signal generated accompanying the dialing causes the on-hook unused telephone to receive 35V. Voltage is applied. The ringer circuit of the telephone in the on-hook state may erroneously detect the voltage based on the dial pulse signal as a voltage based on the ringing signal when an incoming call is received, and may cause a resonance phenomenon that the ringer operates.

Therefore, conventionally, in order to suppress the occurrence of such a resonance phenomenon, the threshold voltage of the ringer circuit is increased by four.
It is set to about 0V. As a result, in the case of a voltage (70 V) applied to the telephone at the time of a regular incoming call, the voltage exceeds the threshold value, so that it is determined that the incoming call has been made and the ringer rings, and another telephone of the parent and child telephones makes a call. In the case of a voltage (35 V) based on the dial pulse signal when the ringing is being performed, the voltage is less than the threshold value, so that it is determined that a call is made (dial) and the ringer is not sounded, so that the ringer is not generated by mistake. The ringer circuit is formed of a one-chip IC.

[0005]

However, with the recent spread of the ISDN network, general telephones may be connected via a terminal adapter (TA). In such a case, when the TA receives the incoming call signal, it sends a call signal to the telephone, and determines that the telephone receiving the call has received a call, and rings the ringer.

[0006] However, some TAs have a low calling voltage of 35 V or less.
Then, in the case of a telephone provided with the above-described resonance prevention function, the ringing signal from the TA is determined as a dial pulse signal from another telephone of the parent and child telephones, and the ringer may not be formed. In other words, when such a TA is used, there is a problem that an incoming call cannot be received by the telephone.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has as its object to solve the above-described problems and to suppress the occurrence of resonance phenomena while maintaining various types of T type.
The present invention provides a telephone which can be applied to A and can receive a call normally (ring a ringer).

[0008]

In order to achieve the above-mentioned object, a telephone according to the present invention detects the voltage of a ringing signal at the time of an incoming call, and when the detected voltage level is equal to or higher than a threshold value, a ringer. It is assumed that the telephone has a ringer function for ringing. A means for switching the operating conditions of the ringer function is provided in conjunction with a line type changeover switch provided in the telephone main body (the method of linking mechanically and electrically is optional). The switching means is configured to have a function of lowering the threshold value, which is a criterion for determining whether to sound the ringer when the line type switch is in a tone (claim 1).

With this configuration, when the line type changeover switch is set to a mode other than tone, that is, when the line is set to a pulse line, the threshold value is set to a voltage higher than a voltage based on a normal dial pulse signal. Therefore, in a case where a plurality of telephones are connected in parallel to a pulse line and used as a so-called parent-child telephone, dialing to make a call from one telephone causes a voltage based on the dial pulse signal to the other telephone in an on-hook state. It takes. However, since the voltage is sufficiently lower than the voltage based on the ringing signal based on a normal incoming call, the voltage becomes lower than the threshold value, and the ringer function does not judge the ringing signal and does not ring the ringer. Therefore,
Resonance is prevented.

On the other hand, when the switch is a tone, the operating condition is switched by the switching means, and the threshold value is lowered. Therefore, even if a call signal of a low voltage level is sent from the terminal adapter, there is no ringer prohibition processing based on the voltage level as in the above-described pulse line, so that the call of the low voltage level is not performed. It can judge the signal and sound the ringer.

[0011] Further, when a plurality of telephones are connected in parallel to form a parent / child telephone on a general push line (line type changeover switch is tone) instead of a terminal adapter, when one of the telephones makes a call. Will only output a tone signal from the phone,
Since no dial pulse signal is generated and there is no erroneous determination as the voltage of the ringing signal based on the incoming call, the ringer does not ring.

In the present invention, "the line type changeover switch is a tone" means that a switch is set for selecting a push line regardless of its name. In recent telephones, even if the telephone is set to a pulse line, it is possible to receive various services by generating pseudo tone signals after connecting to the other party by operating various switch buttons. Although the present invention is not limited to such a switch for generating a pseudo tone signal, the present invention has no relation to the switch and the change of the threshold value of the criterion is interlocked with the switch or interlocked. You don't have to.

[0013]

FIG. 1 shows a main part of an embodiment of a telephone according to the present invention. As shown in FIG. 1, the telephone line 1 is connected to the telephone line 1 via the hook switch 2 so as to allow communication. After the hook switch 2 (on the side of the telephone body), a rectifying circuit 3 for adjusting the polarity of the telephone line is supplied to a two-core / four-core converter and a communication circuit 4 for adjusting the level of transmission and reception. The communication circuit 4 is connected to a handset 5 having a microphone and a speaker. Thereby, the voice transmitted from the telephone line 1 is output from the speaker of the handset 5. Conversely, handset 5
The voice signal of the user input from the microphone is transmitted to the telephone line 1 via the communication circuit 4 → the rectifier circuit 3 and the hook switch 2. Since such a configuration is the same as that of a generally used telephone, a detailed description thereof will be omitted.

On the other hand, the telephone has a function of ringing a ringer upon receiving a call signal at the time of an incoming call. Specifically, the level detection circuit 6 and the ringer circuit 7 which are connected so as to be branched from the telephone line 1 before the hook switch 2
And a buzzer 8. That is, the voltage of the telephone line 1 is monitored by the level detection circuit 6, and when the voltage is equal to or higher than a preset level (voltage value), a detection signal is output to the ringer circuit 7. The ringer circuit 7 which receives this,
A ringer sounds when an AC voltage having a predetermined frequency is applied to the buzzer 8 made of a piezoelectric element. Note that a speaker may be used instead of the buzzer 8. The level detection circuit 6 and the ringer circuit 7
Is realized by, for example, one IC chip (TA31002P or the like).

Further, as is well known, a telephone line includes a pulse line and a push line, and generates a pulse signal accompanying dialing for the former line, and generates a tone signal for the latter line. Is caused to occur. And, of course, in the case of a button-type phone,
In order to be applicable to both lines, the telephone body is provided with a line type changeover switch 10 composed of a slide switch for changing the type of the line, and the user has contracted himself. The line type changeover switch 10 is set at a predetermined position according to the type of line. Thus, when the dial button is pressed (dialed) to make a call, a pulse signal or a tone signal is generated according to the position of the switch.

Here, in the present invention, there is provided a changeover switch 11 for changing the operating condition of the ringer function, that is, the threshold value used as a criterion for judging whether or not the signal is a calling signal in the level detection circuit 6. The changeover switch 11 is mechanically linked to the line type changeover switch 10, and changes the threshold value depending on whether or not the line type changeover switch 10 is a tone. Specifically, it is as follows.

In the case of a normal threshold value, the threshold value is set to a predetermined value equal to or higher than the voltage level of the dial pulse signal and equal to or lower than the voltage level of the ringing signal at the time of incoming call. As a result, the ringer can be sounded only at the time of a true incoming call without causing a resonance phenomenon even in the case of using the parent-child telephone format on a pulse line.

When the line type changeover switch 10 is set to tone, the changeover switch 11 switches to a threshold having a voltage level lower than the above-mentioned normal threshold. Thus, even when the voltage level of the call signal is low, such as TA, the call signal can be reliably recognized and the ringer can be sounded.

[0019]

As described above, in the telephone according to the present invention,
The threshold value of the voltage level serving as a criterion for determining whether to ring the ringer is changed according to the state of the line type switch (tone or not). Can recognize and ring the ringer. Therefore, the present invention can be applied to various types of TAs, and a call can be normally received (ringer rings). Also, when used for pulse lines, setting the threshold value to a normal high value allows the call to be made even if the dial pulse signal voltage generated when another telephone constituting the parent-child telephone makes a call is applied. The occurrence of the resonance phenomenon can be suppressed without being erroneously recognized as a signal.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a preferred embodiment of a telephone according to the present invention.

[Explanation of symbols]

 1 telephone line 6 level detection circuit (ringer function) 7 ringer circuit (ringer function) 8 buzzer (ringer function) 10 line type changeover switch 11 changeover switch

Claims (1)

[Claims] 1. A telephone equipped with a ringer function for detecting a voltage of a ringing signal at the time of an incoming call and ringing a ringer when the level of the detected voltage is equal to or higher than a threshold value. Means for switching the operating conditions of the ringer function in conjunction with a switch, wherein the switching means lowers the threshold value as a criterion for determining whether to sound the ringer when the line type switch is in tone. A telephone having a function.