KR920000081B1 - Displayer of telephone calling - Google Patents

Abstract

The apparatus displays a busy line state during a telephone communication, when two telephone sets are connected to a single telephone line in a branched state. The apparatus includes: an oscillating section for generating a micro wave frequency; capacitors (CA1,CA2) for blocking audio frequencies; another capacitor (CA3) for blocking the audio frequency of the capacitor (CA1); a detecting section for generating pulse signals of a certain width in accordance with the output of the oscillating section; a driving section for varying its own output in accordance with the output of the detecting section; and a displaying section for being energized in accordance with the inputted signals.

Description

Phone busy indicator

1 is a block diagram of a telephone line configured with a busy indicator of the telephone according to the present invention.

2 is a block diagram of a telephone busy indicator connected according to the present invention;

3 is a detailed circuit diagram of FIG.

* Explanation of symbols for the main parts of the drawings

1: Phone station 2 and 2 ′: Phone busy indicator

3: Phone B 4: Phone A

5 and 6: oscillator A and oscillator B 7 and 8: detector A and detector B

9 and 10: drive unit A and drive unit B 11 and 12: display unit A and display unit B

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phone busy display, and more particularly, to a phone busy display for displaying busy display when two phones are connected to one trunk line in parallel.

In general, when two phones on a trunk line are connected in parallel, when one phone is in a call and you do not know it and pick up the other phone's handset, the communication sensitivity is reduced and the contents of the call are leaked.

Accordingly, the present invention solves the above-mentioned drawbacks when using parallel connection of two phones on a trunk line, so as not only to induce a smooth call but also to recognize the busy display of both phones in order to prevent two phones from being used at the same time. The purpose is to provide a configured busy indicator.

According to the present invention, whenever a telephone handset is picked up or released, a constant signal is generated to be received by another telephone and displayed on the display unit, thereby preventing an interruption during a call.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

FIG. 1 is a block diagram of a telephone line in which a telephone busy indicator according to the present invention is constructed, wherein trunk lines L1 and L2 of telephone station 1 are connected to existing telephones A4 and B3. Telephone busy indicators 2 and 2 'according to the invention are respectively connected in parallel to the telephones A 4 and B 3, for example, a handset of the telephone A 4 (not shown in the drawing). For example, a telephone busy indicator 2 'connected in parallel to the telephone A 4 is operated so that each of the busy indicators 2 and 2' is configured with LEDs (not shown). At the same time, the phone B 3 is informed that the telephone B 3 is busy. If the handset of the phone B 3 is lifted, the LED is turned off and the phone A 3 is on the phone B 3 side. It was configured to recognize.

FIG. 2 is a block diagram (block A of FIG. 1) in which the phone busy indicators 2 and 2 'according to the present invention are interconnected. The left and right configurations are the same. The operation will be described.

The oscillator A (5) VDDA for power supply operates in conjunction with the telephone hook switch (not shown), and is connected to the oscillator A (5) via a switch SWA which is turned on only as long as the hook switch is turned ON or OFF. The output terminals of the oscillator A (5) are connected to the telephone trunk lines L2 and L1 via the capacitors CA1 and CA2, respectively, while the connection point of the oscillator A (5) and the capacitor CA2 is directly and the capacitors CA1 and CA2. The connection point of the telephone trunk line L2 is connected to the detection unit A (7) via the capacitor CA3, respectively, and the detection unit A (7) is operated by receiving the operating power from the VCCA terminal, and its output terminal is connected to the driving unit A (9). It is connected to the display portion A11.

The telephone busy indicator configured as described above is interconnected to the telephone company trunk lines L1 and L2 as shown in the figure. The operation is as follows.

For example, if the switch SW1 is attached to and detached by a hook switch (not shown), at the moment of attachment, the supply power supply VDDA operates the oscillation unit A (5) so that its high frequency output passes through the capacitors CA1 and CA3. When the detection unit A (7) is reached, the detection unit (7) detects the frequency and then drives the drive unit (A) 9 to operate the display unit (A11), while the high frequency output is connected to the capacitors CA1 and CB3. After detection by the detection unit B (8) via, the driving unit B (10) is driven by the output signal of the detection unit B (8) to cause the display unit (12) to emit light.

That is, since the display unit A (11) and the display unit B (12) operate simultaneously when the switch SWA is attached and detached once, the display unit displays a busy state (even if only the switch SWB operates). Since the A 11 and the display unit B 12 are turned off so that the state of another telephone can be recognized during a call, it is possible to know whether the wiretap is performed. A detailed description will be made with reference to FIG.

3 is a detailed circuit diagram of FIG. 2 to describe the present invention in more detail.

First, the configuration of the oscillator A (5) is such that the power supply VDD terminal is connected to the connection points of the resistors R1, R2, R3 and R4 via the switch SWA, and one terminal of the crystal X1 is the base terminal of the oscillation transistor Q1, the resistor R1 and The other terminal of the crystal X1 is grounded while connected to the R5 terminal connection point. A capacitor C7 is connected to the emitter terminal and the base terminal of the transistor Q1, and the transistor Q1 is connected to the connection point of the resistor R7 and the resistor R5 at the emitter terminal via the capacitor C5 and grounded.

Further, at the connection point of the collector terminal of the transistor Q1 and the resistor R2, it is grounded through the capacitor C1, and the emitter terminal of the transistor Q1 is connected to the base terminal of the buffer transistor Q2, the connection point of the resistor R3 and the resistor R2 via the coupling capacitor C2. The collector terminal of transistor Q2 is connected to resistor R4 while the emitter terminal is grounded via resistor R8 and then telephone trunk line L2 is connected to emitter terminal of transistor Q2 via capacitor CA1 and L1; The terminal is grounded via capacitor CA2.

Referring to the operation of the configuration, when the switch SWA is turned on, the oscillation transistor Q1 is turned on and oscillated by the crystal X1, and the oscillation frequency is applied to the base terminal of the amplifying transistor Q2 by a coupling capacitor C2 to perform a buffer function. Will be done.

Next, the detection unit A (7) is connected to the TR terminal of the timer IC1 at the connection point of the capacitor CA1 and the L2 via the capacitor CA3, which is grounded via the variable resistor R9 at the TR terminal, and an operating power source for operating the timer IC1. The VCC terminal is connected to the TR terminal of the IC1 via the resistor R10, and is connected via the capacitors C4 and C5 at the connection point between the CV terminal and the DIS terminal of the IC1 and the THR terminal, respectively, while the DIS and THR terminals of the timer IC1 are connected. At the connection point, it is connected to the R terminal of the IC1 via the resistor R11 and then grounded via the capacitor C3 at this terminal, and the high frequency output of the oscillator A (5) via the capacitor CA3 is connected to the TR terminal of the timer IC1. When triggered, one pulse is generated at the Q terminal of this IC1. At this time, the width of the generated pulse is determined by the resistor R11 and the capacitor C5.

Next, the driving unit A 9 has the R terminal of the timer IC1 connected to the PR terminal of the D flip-flop IC2, the D terminal and the Q terminal of the D flip-flop IC2 connected to each other, and the CL terminal via the capacitor C6. After the grounding, the Q terminal of the timer IC1 is connected to the CLK terminal of the D flip-flop IC2. When a pulse is applied from the Q terminal of the timer IC1, a constant voltage is applied at the Q2 terminal of the D flip-flop. Is generated, and when a pulse is applied to the CLK terminal of the D flip-flop IC2 again, the Q terminal of the IC2 falls to the ″ 0 ″ potential. That is, once the pulse is applied to the CLK terminal of the IC2, the Q terminal of the IC2 generates a constant voltage, and if the second terminal is applied twice, the constant voltage is generated again when the ″ 0 ″ potential is added three times.

Finally, the display portion A (11) described above is connected from the Q terminal of the IC2 to the base terminal of the switching transistor TR3 via the resistor R12, and the collector terminal of the transistor TR3 is connected to the IC2 via the light emitting diode LED1. The emitter terminal of the transistor TR3 is connected to the PR terminal and is directly grounded. When the constant voltage at the Q terminal of the IC2 triggers the base terminal of the transistor Q3, the light emitting diode LED1 is turned on. When the potential of the Q terminal becomes ″ 0 ″ potential, the transistor TR3 is turned off and the light emitting diode LED1 is turned off.

Looking at the operation of the two telephone busy indicators of the above-described structure interconnected to the telephone line trunk line, for example, they were attached by a hook switch (not shown). If the VDD voltage is supplied to the oscillator A 5 when the falling switch SWA is applied, the oscillating output of the transistor Q2 triggers the TR terminal of the timer IC1 via the capacitors CA1 and CA3, as described above. At the same time the LED LED1 is turned on, the oscillation frequency triggers the TR terminal of the timer IC3 of the detector B8 via the capacitors CA1 and CB3 to emit the light emitting diode LED2 of the display B12.

에 의해)된 것으로 볼 수 있으므로, 송수신 감도에는 아무런 영향을 미치지 않는다.It should be noted that since the capacitors CA2 and CA3 connected to the trunk lines L1 and L2 are DC off, they are independent of the DC voltage (usually about 18V) applied to the trunk lines L1 and L2. Has no effect. In addition, since the oscillation frequency is very high compared to the voice signal, the capacitors CA2 and CA3 are turned off when viewed from the voice signal side.

As it can be seen, the transmission and reception sensitivity has no effect.

In other words, it can be seen that there is no abnormality even when the telephone busy display 2 of the present invention is connected to an existing telephone.

With the built-in indicators of telephone conversations as described above, two telephones are connected to the Korean line in parallel to prevent accidental interception or eavesdropping during the call, and to prevent two telephones from being used at the same time. By displaying, there is an excellent effect of reducing unnecessary consumption of 2 currents.

Claims (3)

In order to use two or more telephones connected in parallel to the Korean line, a telephone busy indicator that is configured on the corresponding number of telephones to receive a call signal and indicates that the telephone is busy by a light emitting diode or the like when another telephone is busy. An oscillator A (or oscillator B) 5 or 6, which is connected from a power supply VDDA (or VDDB) via a switch SWA (or SWB) and outputs a high frequency in accordance with the ON operation of the switch SWA (or SWA); From the capacitors CA1 and CA2 (or B1 and B2) for interrupting voice capacitors, which are respectively connected from the oscillator A (or oscillator B) (5 or 6) to block the voice frequency, and from the voice frequency blocking capacitor CA1 (or CB1). Capacitor CA3 (or CB3) for interrupting the speech frequency, the oscillator A (or oscillator B) (5 or 6) and the capacitor for interrupting the speech frequency Detector A (or detector B) 7 and 8, which are connected from CA3 (or CB3) and generate one pulse signal of a predetermined width in accordance with the operation of oscillator A (or oscillator B) 5 or 6, A drive unit A (or drive unit B) 9 or 10 whose output state is transitioned in accordance with a signal input from the detector unit A (or detector unit B) 7 or 8, and the drive unit A (or drive unit B) And a display unit A (or display unit B) (11 or 12), which is lit in accordance with a signal input connected from (9 or 10). The telephone busy display of claim 1, wherein the switch (SWA or SWB) is configured to interlock with a hook switch of the telephone. 2. The telephone busy display as claimed in claim 1, wherein the driving unit A (or driving unit B) (9 or 11) includes a D flip-flop IC2 (or IC3).

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