JPS61218252A - Display circuit for telephone set - Google Patents

Abstract

PURPOSE:To allow one display element to display reception of a ringer signal, transmission of a dial pulse signal and the operating state of a telephone line by connecting a transistor (TR) turned on/off by a detection signal from a ringer signal detection circuit and a TR turned on/off by a signal from a dial pulse signal generating circuit to the display element. CONSTITUTION:When a ringer signal is received from an opposite party, a detection signal detected by a ringer signal detection circuit 4 turns on/off the 1st display TR 11. Thus, the display element 10 blinks. The 2nd display TR 12 is turned on/off by a dial pulse signal at the transmission of the dial pulse signal to blink the display element 10. When a handset is lifted from a hook base or a function button is depressed to cause hook-off state and close the telephone line, the 2nd display TR 12 is turned on normally by a signal from a dial pulse signal generating circuit, and since a DC voltage obtained from a signal fed from the telephone line rectified by a rectifier circuit is fed to the display element 10, the display element lights up continuously.

Description

[Detailed Description of the Invention] (a) Industrial Application Field The present invention enables a single display element to display ringer signal reception, dial pulse signal transmission, and call status. Related to display circuits for telephones.

(b) Prior art Recently, for example, as described in Japanese Patent Laid-Open No. 59-30347, an electronic telephone uses an integrated circuit to electronically generate a dial pulse signal and transmit it to the other party via a telephone line. is often used. As described in Japanese Unexamined Patent Publication No. 59-75750, such electronic telephones are equipped with a lamp that is turned on to indicate when the telephone is in use.

(c) Problems to be solved by the invention However, with electronic telephones, dialing pulse signals are transmitted to the other party by simply pressing key buttons on the keyboard, so the owner of the telephone is certain that the dialing pulse signals are being transmitted. I'm worried because I can't confirm whether it's being done or not. Therefore, it is an object of the display circuit for a telephone set of the present invention to be able to display the transmission of a dial pulse signal, the reception of a ringer signal, and the display that the telephone line is in use using a single display element. .

B) Means for Solving the Problems The display circuit of the telephone of the present invention includes a ringer signal detection circuit for detecting a ringer signal from a telephone line, and a rectifying circuit for the ringer signal or a signal from the telephone line at one end. a first display transistor connected to the other end of the display element and turned on and off by a detection signal from a ringer signal detection circuit; 1 display transistor and a second display transistor connected to the other end of the display element and turned on and off by a signal from a dial pulse signal generation circuit.

(E) Function Since the display circuit of the telephone of the present invention has the above-described configuration, when a ringer signal is received from the other party, it is detected by the ringer signal detection circuit; The first display transistor is turned on and off by the detection signal. Therefore, when the first display transistor is turned on or off, the display element blinks to indicate that a ringer signal is being received, and when a dial pulse signal is transmitted, the second display transistor is turned on or off by the dial pulse signal. The display element blinks to indicate that the dial pulse signal is being transmitted. When the handset is hooked off or the telephone line is closed by lifting the handset from the hook stand or by operating a function button, the second display transistor is always turned on by a signal from the dial pulse signal generation circuit, and the display element Since a DC voltage obtained by rectifying the signal supplied from the telephone line with a rectifier circuit is applied to the display element, the display element lights up continuously to indicate that the telephone line is in use.

(f) Example An example of the telephone according to the present invention will be described with reference to the drawings.
1) is a first rectifier circuit connected to the telephone port s(Lt)(Lt) via the first and second changeover switches (2) and (3);
(4) is the first rectifier circuit (1) K-connected ringer;
A signal detection circuit whose output is a matching transformer (5)
and is applied to the speaker (7) via the third changeover switch (6). (8) is a second rectifier circuit for obtaining a DC voltage for operation from an AC signal supplied from the telephone line (Lt) (Ll) via the first and second changeover switches (2) and (3); 9) is a display circuit in which the positive electrode at one end is connected to the first
A light emitting diode (1)) connected to the rectifier circuit (1) and the second rectifier circuit (8) has a collector connected to the negative electrode of the light emitting diode α1, and an emitter connected to the first rectifier circuit + IJK. On the other hand, a first display transistor I is turned on and off by a detection signal from the ringer detection circuit (4) supplied to its base, and a light emitting diode a whose collector is connected to the collector of the first display transistor αυ.
The negative electrode of 8 is connected, and the emitter is connected to the second rectifier circuit (8
) and a second display transistor α2 connected to the second display transistor α2. Country 0 is a dial pulse signal generation circuit that generates a number of dial pulse signals corresponding to the number of pressed key buttons when a key button on the keyboard α is pressed. It has a DP terminal that generates a muting signal, and an MT terminal that outputs a muting signal that changes from high level to low level when the key button is pressed, and the DP terminal and MT terminal are connected to the 2 display transistor a
Connected to pace 3. The wholesaler is the second rectifier circuit (
8) A K-connected dial transistor generates a dial signal by intermittent DC voltage of the second rectifier circuit (8) every time the dial pulse signal generated from the dial signal generating circuit a3 is applied, and connects the telephone line. (Lt) (L
t) to the other party. A speech circuit is connected to the second rectifier circuit (1) via a fourth changeover switch a9, and a telephone receiver (2) is connected thereto. (21) is a line transformer that is selectively connected to the second rectifier circuit (8) through the speech circuit 08 and the fourth changeover switch (IIK), and its output is applied to the amplifier circuit @. The on/off transistor connected between the 2nd rectifier circuit (8) and the 4th changeover switch 0!J is turned on and off by the muting signal generated from the dial pulse signal generation circuit (13) and connected to the telephone line (Lt) (Lt). When transmitting the dial signal, the DC voltage rectified by the second rectifier circuit (8) is not supplied to the amplifier circuit @ by 5Kt.■ is turned on and off by the dial pulse signal from the dial pulse generation circuit a3. It is a muting transistor.

Note that the first and second changeover switches (2) and (3) are positioned in the state shown in the figure when in a standby state where they are waiting for a call from the other party. When the function button of the generator circuit α is switched to the hook-off state, it is switched to a state different from that shown in the figure, and the third switch (6) is in the state shown when the function button is hooked-on, and the fourth switch The switch a-yu is in the state shown in the figure when the handset (2) is on the hook stand, and when the handset (2) is lifted from the hook stand, it is switched to the side opposite to that shown in the figure.

Also, the audio circuit that transmits the audio signal to the speech circuit α frame or the line transformer 121) is omitted because it is not the gist of the present invention.

Next, to explain the operation of the display circuit of the telephone of the present invention, the handset and receiver ■ is placed on a hook stand (not shown), and the handset is hooked on without operating the function button (not shown) and placed in a standby state as shown. At a certain time, when a ringer signal is transmitted from the other party, the ringer signal is applied to the first rectifier circuit (1) via the first and second changeover switches (2) and (3) and is rectified. The signal is supplied to a ring signal detection circuit (4) and converted into a ring signal of a predetermined period. The call signal is transmitted through the matching transformer (5) and the third changeover switch (6).
) is applied to the speaker (7), and a ringing tone is emitted from the speaker (power).Along with this, the detection signal converted into a pulse signal with a predetermined period by the ringer signal detection circuit (4) is displayed on a second display. Joins the base of transistor 02,
The first display transistor αυ is intermittently turned on and off.

On the other hand, since a smoothed current obtained by smoothing the ringer signal with a capacitor (5) flows through the positive electrode of the light emitting diode Ql, a smoothed current flows through the light emitting diode Q (etc.) every time the first display transistor αυ is turned on. Since the light emitting diode (10) lights up to indicate that a ringer signal has been received, even a telephone without a speaker (7) can know that a ringer signal is being received.

When the owner hears the ringing tone and picks up the handset (a) from the hook stand, the first, second and fourth changeover switches (2)
(3) (1) is switched to the side opposite to that shown in the figure and becomes hook-off state. Then, the polarity of the voltage supplied from the telephone line (Lt) is determined by the second rectifier circuit (8), and the voltage is applied to the positive electrode of the light emitting diode a. On the other hand, at this time, the signal at the terminal MT of the dial pulse signal generation circuit α is at a high level, and this signal is applied to the base of the second display transistor 020 and turns on the @2 transistor 0, so that the DC voltage is light emitting diode Ql
The signal flows through the first display transistor QB and lights up the light emitting diode (II) to indicate that a call is in progress.

The foregoing is a case in which a ringer signal transmitted from the other party is received, but a display is also made when the owner transmits a dial pulse signal. That is, in the standby state shown in the figure, the second rectifier circuit (8) is disconnected from the telephone line (L,) (L,) and does not generate a DC voltage, so the dial pulse signal generating circuit α3+ is deactivated and no signal is generated. Does not occur. Therefore, the second display transistor a is turned off and the light emitting diode α1 does not emit light.

Next, when making a call to the other party, press the function button provided in the dial pulse signal generation circuit (The above-mentioned changeover switches may be changed by lifting the handset from the hook base.) Then, as before, the voltage flowing through the telephone line (Ll) (LK) is the second rectifier circuit (8)K.
, resulting in a polarized voltage. The voltage is supplied to the dial pulse signal generating circuit α3, which operates the dial pulse signal generating circuit αJ, and connects the terminal MT as described above.
The signal is set to high level, the second display transistor 02 is turned on, and the light emitting diode αl is lit. When the key buttons of the keyboard (14) are pressed in order to call the other party in such a state, a number of dial pulse signals corresponding to the pressed key buttons are generated from the terminal DP, and a negative muting signal is generated from the terminal MT. generate a signal.

The dial pulse signal is applied to the dial transistor 0η, and the dial transistor αη is turned on every time the dial pulse signal is applied, thereby intermittent the DC voltage of the second rectifier circuit (8). Thereby, the telephone line (Lt) (Lt
) is also intermittent and becomes a dial signal that is transmitted to the other party via the exchange. The dial pulse signal is passed through a diode (formerly) to the second display transistor α
He will also join the 3rd pace. At this time, since the signal at the terminal MT of the dial pulse signal generation circuit a3 is at low level,
The second display transistor α2 is turned on when the dial pulse signal is applied, causing the light emitting diode αυ to blink, indicating that the dial pulse signal is being transmitted. Since this dial pulse signal has a different period from the ringer signal, the blinking interval of the light emitting diode α is also different when receiving the ringer signal and when transmitting the dial pulse signal, so it is easy to determine which state it is in. We can separate.

Furthermore, when transmitting the dial pulse signal, the muting signal from the terminal MT becomes low level, which turns off the switching transistor (c).
This is to prevent the DC voltage output from the amplifier circuit (c) from being applied to the amplifier circuit K through the switching transistor (c) and being unnecessarily lowered. At this time, the noise signal generated by the amplifier circuit @ is suppressed by the muting transistor (c).

When the transmission of the dial pulse signal to the other party is completed, the signal at the terminal MT of the dial pulse signal generating circuit 0 becomes high level again, so the signal passes through the diode α and is applied to the base of the second display transistor α. , the M2 display transistor (Iz is turned on. Also, the light emitting diode a
As described above, since the DC voltage rectified by the second rectifier circuit (8) is applied to [, the light emitting diode ti
[ lights up continuously to indicate that the telephone line (Ll) is in use.

After the transmission of the dial pulse signal is completed, a calling signal for calling the other party is sent from the telephone line 1)1(I+)(Lt) through an audio circuit (not shown) to the line transformer (21) and to the amplifier circuit (c). At this time, the DC voltage rectified by the second rectifier circuit (8) is supplied to the amplifier circuit (2) via the switching transistor (c).
is in operation and the ringing signal is amplified and applied to the speaker (7).Therefore, the speaker (7) emits a sound so that the owner can hear the ringing tone without lifting the handset. When it is confirmed that the telephone line (L+) (Ly) has been closed by listening to the ring tone and lifting the handset, etc., when the handset is lifted, the fourth changeover switch 0 changes to the opposite direction as shown. The switch is switched and the speech circuit α is activated.The handset (A) is then connected to the telephone line (Ll) (Lx), so the owner's message is transmitted from the handset to the speech circuit α. circuit and first
and the telephone line (through the second changeover switch (2>(3))
L, )(L,)K is added and transmitted to the other party. Also, messages from the other party can be heard through the handset (A) via the reverse route to the handset (A).

(g) Effects of the invention As described above, the display circuit of the telephone of the present invention has a display element K.
Since the first display transistor, which is turned on and off by the detection signal from the IJ ringer signal detection circuit, and the second display transistor, which is turned on and off by the signal from the dial pulse signal generation circuit, are connected, one display element can handle the ringer signal. It is possible to display the reception of a signal, the transmission of a dial pulse signal, or the use of a telephone line, and has the advantage of being able to confirm the transmission of a dial pulse signal, especially in electronic telephones.

[Brief explanation of the drawing]

The figure is a display circuit diagram of a telephone according to the present invention. (4)... Ringer signal detection circuit, (8)... Second rectifier circuit, (9)... Display circuit, (II...
Light emitting diode, αυ...first display transistor,
α2...Second display transistor, 03...Dial pulse signal generation circuit.

Claims (1)

[Claims] (1) A ringer signal detection circuit that detects a ringer signal from a telephone line; a display element to which one end is supplied with DC direct pressure obtained by rectifying the ringer signal or the signal from the telephone line with a rectifier circuit; The first one is connected to the other end of the display element and is turned on and off by the detection signal from the ringer signal detection circuit.
The ringer signal detection circuit comprises a display transistor, and a second display transistor that is connected to the other end of the display element together with the first display transistor and is turned on and off by a signal from a dial pulse signal generation circuit, and when a ringer signal arrives, the ringer signal detection circuit When a dial pulse signal is transmitted, the second display transistor is turned on and off to cause the display element to blink, and when the telephone line is closed, the first display transistor is turned on and off to blink the display element. A display circuit for a telephone, characterized in that a second display transistor is always turned on by a signal, and a display element is continuously lit.