JPS6152053A - Dial impulse transmission circuit - Google Patents

Abstract

PURPOSE:To eliminate completely the effect specific to an element by adopting electronic components such as semiconductors for a relay and a choke coil as electronic circuit so as to eliminate an inductive component. CONSTITUTION:A constant current circuit section 101 is designed to act like a choke coil when a photocupler PC0 is turned on and a photocupler PC1 is turned off and to act like a dial impulse transmission circuit when the photocoupler PC1 is turned on/off. A nonpolarizing circuit section 102 nonpolarizing a power supply voltage of a telephone line is a nonpolarizing circuit cancelling the voltage polarity of an N-P-N junction of a semiconductor such as a constant current transistor TR1 and supplies a voltage at which the titled circuit is operated always even if the line voltage polarity is changed. Since no inductive component exists, generation of surge, crosstalk or noise is eliminated and the noise figure is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is used in telephone switching equipment and terminal equipment. In particular, the present invention relates to a dial impulse transmission path using an electronic circuit in a circuit that generates an impulse such as a terminal device or an interoffice signal.

[Conventional technology]

2. Description of the Related Art Telephone switching equipment and terminal equipment transmit impulses and relay impulses using relays that can easily obtain voltage resistance characteristics for telephone lines. On the other hand, during calls or communications, cold current wires or relays that can provide high AC impedance are inserted into the line to provide the required DC,
Obtains AC characteristics.

FIG. 3 is a diagram showing an example of a conventional dial impulse sending circuit. In this example, the operation of receiving impulses from the slave station and relaying the impulses to the exchange will be explained.

Relay A is for forward monitoring and impulse reception, and switch a is its contact. The switch C is a contact point of a relay C which is not shown but operates during impulse transmission, and the cold flow coil RET has low impedance in direct current and high impedance in alternating current.

The dial impulse transmission is performed by operating relay C and operating/restoring relay A to follow the received impulse. After sending out the dial impulse, the electrical appliance A is activated and the relay C is put into the recovery state, thereby inserting the cold current line RET into the line and setting up a telephone call or communication line.

Here, the resistor R is for terminating the line during dialing, the resistor R1 is for removing the inductance of the cold current ring RET, and the resistor R2 is for protection.

[Problem that the invention seeks to solve]

However, such a conventional dial impulse sending circuit has a problem in that the shortcomings of the relay and the blocking wire constituting the circuit directly become the shortcomings of the circuit.

In other words, with regard to relays, ■ the shape of the element is large, ■ the driving or control power is large, ■ surge voltage is generated due to the inductance of the coil when driving, ■ there is a limit to the number of times it can operate mechanically and electrically. Blocked wire rings have the following disadvantages: ■ Due to inductance, crosstalk and noise are likely to occur due to energy radiation between telephone lines and electrical appliances; ■ The shape is large due to the superimposition of direct current. It has drawbacks such as being bulky and heavy.

These drawbacks are all due to the basic characteristics of the elements used, and as long as similar elements are used, these problems cannot be avoided even if the circuit configuration is changed.

The present invention has been made in view of these conventional problems, and provides a dial impulse output path that eliminates the element-specific effects of conventional elements.

The purpose is to provide.

[Means for solving problems]

The present invention is characterized in that in order to eliminate the element-specific effects of conventional elements, the selection of elements is reviewed and electronic components such as semiconductors are used.

That is, two Darlington-connected transistors, and the collector and emitter of a transistor subsequent to the two Darlington-connected transistors are connected to a two-wire line via a resistor at least on the emitter side,
The base of the first transistor of the two Darlington-connected transistors is connected to the midpoint of a resistor divider circuit connected between the two-wire lines, and a first photocoupler is connected in parallel between the collector and emitter of the first transistor. means to which the driven part of the second photocoupler is connected in series to the base current supply circuit of the preceding transistor, and to apply a switching current corresponding to the impulse to the driving part of the first photocoupler. and means for applying an open current to the driving section of the second photocoupler during the period of sending out the impulse.

[Effect]

In the present invention, the elements that constitute the dial impulse sending circuit, especially the electric appliances and the cold flow coil, are electronicized using electronic components such as semiconductors, thereby eliminating the inductance and reducing the inductance that the conventional elements had. Intrinsic effects can be completely eliminated.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram illustrating an embodiment of the present invention. In FIG. 1, there is a constant current circuit section 101 between the inside of the terminal and the subscriber's line, and a voltage and voltage non-polarization circuit section to ensure normal operation even when the polarity of the power supply voltage of the telephone line is reversed. 102 is connected to the constant current circuit section 101, and a driving section 103 for driving a control half-fidelity element is connected to the constant current circuit section 101.

FIG. 2 is an embodiment of the present invention specifically showing the block diagram shown in FIG. 1 as an actual circuit.

A transistor Tr forming the constant current circuit section 101.

and transistor Tr are Darlington-connected, and a resistor R0 is connected between the collector and base of the Darlington-connected front-stage transistor 7'ro, which constitutes a base bias circuit. A resistor R1, a resistor R2, and a capacitor C are connected in parallel between the base of the transistor Tro and the emitter of the transistor Tr. Furthermore, a photo SC is connected in series with the resistor R0 as a driven part of the photo coupler PCo.
A photo SCR is connected in parallel between the collector and emitter of the transistor Tr0 as a driven portion of the photo coupler PC1.

Diodes Do, D+, D2, and Dl constituting the power supply voltage non-polarization circuit section 102 are connected in a bridge configuration.

The drive section 103 is connected to the drive sections of the photocoupler PCO and the photocoupler PCI, that is, the photodiodes and their drive circuits.

Note that the control of this drive unit 103 is to turn the photocoupler PCo "off" when sending dial impulses, and to turn the photocoupler PC1 "on/off" for each dial impulse.
After sending out the dial impulse, the photocoupler PC is turned off and the photocoupler PC0 is turned on.

In this embodiment, a cold current circuit and a dial impulse sending circuit are combined, and the claw and toe coupler p of the drive unit 103 are combined.
The operation is switched depending on the combination of the operation state settings of c, , and pc.

In other words, the cold current circuit operates when the photocoupler PCo is "on" and the photocoupler PCI is "off," and the photocoupler PCo is "off" and the photocoupler PC+ is "on/off."
It is set to operate as a dial impulse sending circuit when set to "Off".

In the cold current circuit operation, the photocoupler PCO is "on", the photocoupler PC is "off", and the photocoupler PC1, which is connected in parallel with the Darlington-connected transistor Tro, is considered not to be connected. be considered. On the other hand, when the photocoupler PCO connected to the bias circuit is turned on, the constant current circuit section 10
1 control Darlington connection transistor Tr0, Tr
, is supplied with a bias voltage and a base current, and operates as a constant current circuit exhibiting constant current characteristics determined by resistor R2.

The characteristic of a constant current circuit is that the current does not change even when the voltage supplied to both ends changes (constant current), and the AC impedance defined as [voltage change / current change] is large. can get.

On the other hand, it exhibits low impedance in terms of direct current, and achieves the same function as conventional flow blocking wires.

As a dial impulse sending circuit, a photocoupler P is used.
, Co are "off", the bias voltage and base current to the Darlington connection transistors Tr0, TrI are not supplied, and the previous stage transistor Tro
becomes a cutoff, but the transistor T r + in the subsequent stage
When the photocoupler PCI is turned on, the base current is supplied and the switching operation region is turned on, and when the photocoupler PCI is turned off, the base current supply is stopped and the switching operation region is turned off. As a result, the “on/off” control of the photocoupler PCI
A dial impulse output path of electronic contacts switching at 411 can be realized.

Non-polarization circuit section 10 that non-polarizes the power supply voltage of the telephone line.
2 is the N of the semiconductor such as the constant current transistor Tr1.
- This is a non-polarizing circuit that cancels out the voltage polarity of the P-N junction, and can supply a voltage that can always operate even if the line voltage polarity changes.

Although this embodiment shows an example in which the dial impulse sending circuit is applied to the terminal device side, a similar circuit can also be applied to the exchange device side. Since transistors include, for example, N-P-N junction type and P-N-P junction type, this can be configured and realized regardless of the presence or absence of the non-polarization circuit of this embodiment.

〔Effect of the invention〕

By adopting the configuration described above, the present invention has the following advantages: 1. The circuit element is extremely small and lightweight; 2. The drive or control voltage is small; 2. There is no inductance, so surges and crosstalk are reduced. , the generation of noise is eliminated, and the noise tolerance can be increased; ■ The electronic switch has no mechanical parts, so it has a semi-permanent lifespan, so it is easy to maintain and is economical; ■ The contact current , the voltage withstand capacity can be set by selecting the final stage transistor, minimizing circuit constraints; ■ cold current and impulse output paths can be combined into one circuit, making it possible to reduce the number of circuit components, etc. The effect of this can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a diagram showing a specific example of the circuit of the present invention. FIG. 3 is a diagram showing an example of a conventional dial impulse sending circuit. 101: constant current circuit section, 102: non-polarizing circuit section for non-polarizing the power supply voltage of the telephone line, 103: driving section for driving the control semi-solid element.

Claims (1)

[Claims] (1) Two Darlington-connected transistors, and the collector and emitter of the transistor in the subsequent stage of these two Darlington-connected transistors are connected to the two-wire line through a resistor at least on the emitter side, and the Darlington connection is described above. The base of the transistor at the front stage of the two transistors is connected to the midpoint of the resistor divider circuit connected between the two-wire line, and a first photocoupler is connected in parallel between the collector and emitter of the transistor at the front stage. A driven part of the second photocoupler is connected in series to the base current supply circuit of the transistor in the preceding stage, and a switching current corresponding to the impulse is supplied to the driving part of the first photocoupler. and means for applying an open current to the drive section of the second photocoupler over a period during which the impulse is transmitted.