KR960001113B1 - Hook switch circuit of wired telephone - Google Patents

Abstract

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Description

Hook switch circuit of wired telephone

1 is a circuit diagram showing a hook switch circuit of a conventional landline telephone.

2 is a circuit diagram showing a hook switch circuit of the landline telephone of the present invention.

Figure 3 is a flow chart showing a call control process of the landline telephone of the present invention.

* Explanation of symbols for main parts of the drawings

11: Bell signal line part 12: Bridge rectification part

13: piezo sound generating unit 14: transmitting and receiving circuit unit

15: microcomputer RL1: first switching means

RL2: second switching means Q1, Q2: switching transistor

The present invention relates to a hook switch mounted on a landline telephone and capable of switching a ring signal and a telephone circuit of a telephone line. In particular, a telephone switch is provided inside the telephone to control the switching means by a microcomputer. It is to facilitate switching between the call circuit and the reception standby state.

A conventional landline telephone is a telephone line consisting of a balanced two-wire system (TIP, RING), as shown in FIG. 1, with a bell signal line unit 1 for receiving a bell signal (AC signal), and a call with a bell signal. Hook switch SW1 (SW2) for switching the circuit, bridge rectifier (2) for impedance matching and telephone line DC low voltage rectification between the telephone line and the telephone line, and the bell signal received through the bell signal line unit (1) Piezo sound generating unit (3) for amplifying and generating a sound, and a transmission and reception circuit (4) for generating a corresponding communication (call, dial signal) sound between the telephone presses. C1 is a capacitor, R1 is a resistor, and D1-D4 is a diode.

As shown in FIG. 1, the conventional landline telephone configured as described above has the primary hook switch SW1 turned off and the secondary hook switch SW2 connected to the contact point a when the user receives the telephone. When switched to the on state, the telephone exchange receives the signal through the TIP line, that is, the signal line unit 1 composed of the resistor R1 and the capacitor C1.

At this time, the signal signal is rectified by the bridge rectifying unit 2 and the DC voltage of the telephone line is rectified and input to the piezoelectric sound generating unit 3, so that the signal of the impedance matching DC rectified is amplified to generate piezo sounds.

Therefore, the telephone receiver can know that the call is received from the outside when the telephone is received. Then, when the user lifts the handset to send and receive a telephone, the primary hook switch SW1 is turned on and the secondary hook switch SW2 is connected to the contact point b to turn the fraud hook switch to the off state. (The hook switches SW1 and SW2 are interlocked.)

Therefore, the TIP line, that is, the resistor R1 and the condenser C1 in the bell signal line unit 1 receiving the bell signal are short-circuited and constitute a call circuit, so that telephone subscribers communicate with each other through the transmission and reception circuit unit 4. Can be done.

However, the conventional wired telephone switches the ring signal reception possible state and the call enabled state (transmission / reception function state) by using hook switches SW1 (SW2) interlocked with each other. Since the on / off operation is performed by the weight of the handset, the handset becomes incapable of communication when the handset is out of position and the hook switch knob is exposed to the outside of the wireline telephone. There was a problem that a malfunction of SW1) (SW2) occurs.

The present invention is provided with a switching means for switching the call and the reception standby state in order to solve such a conventional problem and to control the switching means by the microcomputer to perform the switching of the telephone call circuit and the reception standby state accurately, The purpose and purpose of the present invention are to prevent a malfunction due to the use of a hook switch.

First, as shown in FIG. 2, the landline telephone of the present invention has a ring signal line section 11 for receiving a bell signal (AC signal) in a telephone in which a telephone line is configured with a balanced two-wire type (TIP, RING). And a first switching means RL1 for switching the call circuit with the bridge rectifier 12 for the impedance matching between the telephone line and the inside of the telephone and the CD voltage rectification of the telephone line, and the bell signal generator 11. A piezo sound generator 13 for amplifying and generating a ring signal, a song and sign circuit unit 14 for conducting a call between telephone subscribers, the piezo sound generator 13, a song and a sign circuit circuit 14 The second switching means RL2 for switching the switch, the switching transistors Q1 and Q2 for driving the switching means RL1 and RL2, and the microcomputer 15 for switching and controlling the switching means in accordance with the determination of the key input. ) Corresponding to the key signal pressed by the telephone key unit 17 It consists of the DTMF myth generation unit 16 which generates a frequency, where reference numeral R2 is a resistor, C2 is a capacitor, and D5-D8 is a diode.

In addition, as an embodiment of the present invention, the switching means RL1 and RL2 are constituted by a relay or an electronic switching element.

When the switching means RL1 and RL2 are implemented as relays, as shown in FIG. 2 and FIG. 3, the microcomputer 15 first detects whether the user is currently using a telephone. If not, the piezo sound generator 13 determines whether a bell signal is generated through the input terminal P4 of the microcomputer 15.

As a result of the determination, when the bell signal is generated, it is detected whether the user presses the special key # (which is a predetermined key value for the hook-off) of the telephone key unit 17.

This can be seen by searching the interfacing lines D0-D3 between the DTMF signal generator 16 and the microcomputer 15 for generating a unique signal corresponding to the key input.

If the special key (#) is pressed as a result of the detection, the microcomputer 15 determines that the user is currently in a call and outputs a high signal at the output P5 of the microcomputer 15 to output the high signal to the base of the switching transistor Q2. By turning on and turning on, the common terminal f of the relay RL2 is connected to the contact g, so that the piezo sound generator 13 is switched to the transmission and reception circuit 14 so that the user can make a telephone call. have. In this case, since the transistor Q1 is turned on, the common terminal c of the relay RL1 is connected to the contact point d to block the bell signal of the bell signal line unit 11 so that the user can make a phone call. .

After that, when the user completes the telephone call, the microcomputer 15 detects whether the special key # (which is a predetermined key for hook-on) of the telephone key unit 17 is pressed and then presses the microcomputer 15 of the microcomputer 15. The output terminal P5 outputs a low signal so that the switching transistor Q2 is turned off so that the common terminal f connected to the contact g of the relay RL2 is connected to the contact e. (14) is switched to the piezo sound initiation unit 13 to maintain the reception standby state.

At this time, since the transistor Q1 is also turned off, the common terminal c of the relay RL1 is also switched to open with the contact d, so that a bell signal input through the TIP line, that is, the bell signal line part 11, is generated. It is to maintain the state.

As described above, a switching element for switching the transmission and reception circuits is provided inside the wired telephone, and the telephone communication circuit and the reception standby state can be easily switched by the control signal of the microcomputer. There is an effect that can prevent branch malfunction.

Claims (2)

DTMF signal generation unit 16 for generating a frequency corresponding to the key signal pressed by the telephone key unit 17, and microcomputer 15 for switching and controlling the switching means in accordance with the output signal of the DTMF signal generation unit 16; And the switching transistors Q1 and Q2 that are turned on and off by the control signal of the microcomputer 15, and the bell signal line section 11 for receiving the bell signal by the switching transistor Q1. A wired line consisting of a first switching means RL1 for switching the circuit, a piezo sound generator 13 by the switching transistor Q2, and a second switching means RL2 for switching the transmission and reception circuit unit 14. Hook switch circuit of telephone. The hookswitch circuit of claim 1, wherein the first switching means (RL1) and the second switching means (RL2) comprise a relay.