KR960000654Y1 - Auto hold-cancel circuit using hold circuit and pulse - Google Patents

Abstract

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Description

Automatic hold release circuit using hold circuit and fill

1 is a conventional hold circuit diagram.

2 is a block diagram of an automatic hold release circuit according to the present invention.

3 is a detailed circuit diagram of the FIG. 2 block diagram.

* Explanation of symbols for main parts of the drawings

100: interface circuit portion 200: hold circuit portion

300: hold automatic release unit 400: dial circuit unit

500: call circuit 600: hold music circuit

CH1: Choke transformer R1 to R15: Resistance

C1 to C7: Capacitor SCR: Thyristor

Q1-Q5: transistors D1-D5: diodes

ZD1: Zener Diode HS1, HS2: Hook Switch

SW1: Hold switch LED1: Light emitting diode

The present invention relates to a hold circuit of a telephone and an automatic hold release circuit that releases a hold operation by using a pulse of a trunk line. Particularly, the hold operation of a telephone connected to a grounded trunk line during a hold operation is performed by holding a hand set. A hold circuit adapted to this automatic release function and an automatic hold release circuit using pulses of a trunk line.

1 is a conventional hold circuit, when the handset OA_DSET is lifted, the hook switch HS is brought into contact with each other, thereby forming a loop and making a call.

When the user presses the hold switch (SW) to hold a call during a call, the user enters the hold state, and when the handset is put in place, the hold is automatically released.

Referring to FIG. 1, the structure and operating state of a conventional circuit are described with reference to the interface circuit unit 100 of the bridge diode BD, the transistor [Ql + Q2), the light emitting diode (LED) zener diode ZDl, and the resistors R3 to R8. ) Hold circuit 200 of condenser (C1), auto hold section (300), hold switch (S, V) resistor (Rl, R2) capacitor (C2) thyristor (SCR) of hook switch (HS) The dial circuit section 400, the talk circuit section 500 of the transistors Q5 and Q6, the dial IC IC1, and the hold music circuit section 600 of the transistors Q3 and Q4 diodes D2 and D3.

When the operation state of the circuit is described, when the hold switch SW is pressed, current flows through the resistor Rl and is applied to the gate of the thyristor SCR to enable the thyristor SCR to operate and pass through the resistor R2. Is applied to the hold circuit unit 400.

As the current flows through the resistors R5 and R7, a potential difference is generated between the emitter and the base of the transistor Ql, and the transistor Ql is turned on, so that the current passes through the transistor. It flows to R6 and R8 and a potential difference is generated between the emitter and the base of the transistor Q2, and the transistor Q2 is turned "on" to a hold state.

In this state, when the handset is put in place, the hook switch HS is disconnected, so that the current flowing in the hold circuit unit 200 increases and the voltage charged in the capacitor C1 also increases.

At this time, when the user lifts the handset, the current flowing through the hold circuit 200 decreases again, and thus the transistor Ql is turned off because the base voltage of the transistor Ql charged in the capacitor C1 is higher than the emitter potential. As a result, the transistor Q2 and the thyristor SCR are “off” so that no current flows in the hold circuit unit 200, thereby releasing the hold state.

However, in the conventional circuit as described above, in order to release a hold during a call, another parallel telephone connected to the same trunk line is held by pressing a hold switch or setting a handset of a held telephone in place. If the handset is held, the hold is not released and the DC resistance of the CO line rises and the AC impedance is changed in the hold state.

In order to solve the above disadvantages, the present invention is devised as described in detail with reference to the accompanying drawings. First, briefly explaining the configuration of the present invention circuit in FIG. And a hold circuit unit 200 and hold auto release unit 300, a dial circuit unit 400, a call circuit unit 500 and a hold music circuit unit 600.

3, the interface circuit unit 100 always supplies power in a constant direction so as to connect the terminals of the trunk line L1 and L2 to which the 48V DC power is supplied and the terminals of the telephone without affecting the polarity. It consists of a bridge (BRlDGE) circuit to be supplied.

The hook switch HS1 connected to the “+” side of the interface circuit unit 100 serves to separate the hold circuit unit 200 and the dial circuit unit 400.

On the "+" side of the interface circuit part l00, the choke transformer CHl and the resistor Rl for AC impedance adjustment are connected in parallel with the anode of the thyristor SCR, the emitter of the transistor Ql, and the transistor Q3 for deholding. On the "+" side of the interface circuit section 100, a resistor Rl5 for stopping the operation of the call circuit section 500 and the dial circuit section 400 during the hold operation is connected to the collector of the transistor Q5.

The base terminal of the transistor Ql is connected to the resistor R2 connected in parallel to the series configuration of the resistor R3 and the capacitor C1, connected to the collector of the transistor Q4, and the emitter of the transistor Q4 is grounded. The base is connected to the cathode of the thyristor (SCR) through a resistor (R4).

The resistor R5 and the large capacitor C5 are grounded in parallel to the cathode of the thyristor SCR.

In the collector of the transistor Ql, a resistor R6 and a capacitor C2 are connected in parallel to the base of the transistor, and the zener diode ZDl is grounded through the resistor R.

Zener diode ZDl is connected to the base of transistor Q2 through resistor R8, and is connected to the emitter of transistor Q2 through diode D5, and to the emitter of transistor Q2. C4) is grounded.

In addition, the zener diode (ZDl) cathode is connected to the hook switch (HS2) through a resistor (R9) and connected to the base of the transistor (Q5) through the hook switch (HS2), and the emitter of the transistor (Q5) is grounded. The collector of transistor Q2 is connected to the base of transistor Q3 through the parallel connection of resistor R10 and capacitor C3, the emitter of transistor Q3 is grounded and the gate end of thyristor SCR. The capacitor (C7) and resistor (Rl2) for the ground pulse are grounded, and the large capacitor (C6) and resistor (R11) are connected in series with the hold switch (SW1), and one end of the hold switch (SW1) is hook switch (HS1). It is connected to the call circuit part of the) so that it can be held only during the call operation, and the light emitting diode (LEDl) is connected to the ground in series with the resistor (R14) at the cathode of the zener diode (ZDl) to operate during the hold. Display.

When described in detail with reference to the accompanying drawings the operation and effects of the present invention configured as follows.

When the call is in the hook state (HS1) is turned on (ON) state, the current is formed in the dial circuit unit 400 and the call circuit unit 500, the loop is formed to enable the call and dial, the hold switch for the call hold When (SW1) is pressed, current flows through the resistor R11 and the capacitor C6, and a trigger pulse is applied to the thyristor SCR gate to operate the thyristor SCR.

The capacitor C7 and the resistor R12 serve to safely apply the gate trigger signal of the thyristor SCR.

When a trigger signal is applied to the gate of the thyristor (SCR), the thyristor (SCR) conducts and a current flows, and a voltage drop occurs in the resistor (R5) by the current flowing through the transistor (Q4) through the resistor (R4). It operates to lower the base potential of the transistor Ql to make the transistor Ql operate to supply a voltage to the hold circuit 200 through the resistor Rl, and the voltage is supplied to the light emitting diode LEDl through the resistor R14. The light-emitting diode (LEDl) is turned on to indicate the hold state.

In addition, the voltage operates transistor Q5 through resistor R9 to stop communication circuitry 500 and dial circuitry 400 using resistor R15.

The hold music circuit unit 600 is operated using this voltage to send hold music sound to the other party when it is held. Here, the resistors R2 and R3 capacitor C1 stabilizes the operation of the transistor Ql according to the fluctuation of the line.

When the current flows in the hold state, the current flows through the choke transformer CHl and the resistor Rl in series and is grounded to the resistor R5 through the thyristor SCR, and the capacitor C5 is grounded in parallel to the resistor R5. In addition, a current flows through the transistor Ql through the resistor RD to the hold music circuit unit 600, and a current flows through the resistor R14 to the light emitting diode LEDl.

In the above circuit configuration, the choke transformer CH1 and the capacitor C5 maintain the AC impedance and the return loss R [rURN1⊃SS] in compliance with the requirements, and the choke transformer CHl and the resistor Rl. R5) shall be maintained in accordance with the DC resistance sound specification.

Now look at the process of the hold is released automatically.

If you hold the handset of the telephone held in the held state or lift the handset of any parallel phone connected to the same trunk line, a low pulse is applied to the trunk line, and this pulse is applied through the resistor Rl and transistor Ql. It is induced in (R6) and capacitor (C2) and applied to the base to transistor (Q2) through the layered time of the resistor (R6) and capacitor (C2).

When a pulse is applied to the base of the transistor Q2, the base potential of the transistor Q2 is much lower than the emitter voltage, so that the transistor Q2 is operated so that the trunk line voltage of the hold state is high (C3) and the resistor ( It is applied to the base of transistor Q3 via Rl0, at which time transistor Q3 is operated to momentarily ground the anodes of thyristor SCR.

Since the anode voltage of the thyristor SCR is lower than the voltage of the cathode, the thyristor SCR stops operation and is automatically released.

At this time, the voltage charged in the capacitor C5 keeps the gate voltage of the thyristor SCR higher than the anode voltage.

As described above, the automatic hold release circuit using the hold circuit and the pulse provide characteristics suitable to any of the world's regulations in the telephone regulations at the time of holding, and the holding is released automatically by using any telephone connected to the same trunk line. It has a strong point and has stable operation even when the trunk line current changes, so it is convenient to use and can be applied to any circuit.

Claims (2)

In the known hold circuit composed of the interface circuit section 100, the hold circuit section 200, the dial circuit section 400, the call circuit section 500, and the hold music circuit section 600, connected to a held telephone or the same trunk line A hold circuit and an automatic hold release circuit using a pulse, characterized in that it comprises a hold automatic release unit (300) for automatically releasing hold by operating by a pulse induced on a trunk line when lifting a handset of a parallel telephone. The hold auto-release unit 300 controls the transistor Q2 and the output of the transistor Q2 which are operated by a power source applied through the resistor Rl and the emitter-collector of the transistor Ql. A parallel connection is made between a transistor Q3, which is applied to the base through a parallel connection of a resistor R10 and a capacitor C3, turns off the thyristor SCR, and a base of the transistor Q2 and a collector of the transistor Ql. And a diode (D4) capacitor (C4) connected to the resistor (R2) and the emitter of the transistor (Q2).