JPS62180644A - Communication equipment - Google Patents

Abstract

PURPOSE:To prevent malfunction of an exchange of a line by providing a changeover means for connecting selectively a sending means and a holding means and making the impedance of the sending means equivalent to the impedance of the holding means. CONSTITUTION:A current corresponding to a sent dial pulse flows to a light emitting section of a photocoupler T2 when collision supervision is finished and a transistor (TR) of a photodetection section of the photocoupler T2 is turned on/off depending on the light emission of the light emitting section, a TR T1 is turned on/off according to turning-on and -off of the photodetection TR of the photocoupler T2 to send a dial pulse, a relay 2 is turned off and a line L is connected to a communication equipment. In this case, the impedance of the TR T1 and a resistor R2' of the dial pulse circuit 5 is made equivalent to the impedance of a choke coil RET so as not to change the current when the relay 2 is turned off and the current of the line flows to the choke coil RET.

Description

[Detailed description of the invention] 〔Technical field〕 .

Zero Hatsumeki's invention relates to a communication device that performs communication via a line.

[Conventional technology]

Conventionally, this type of equipment, for example, has been used to connect
In a communication device having an automatic calling function that dynamically sends dial pulses and performs communication by forming a line loop, the calling circuit is constructed as shown in FIG.

In FIG. 2, D is a dial pulse sending circuit, L is a telephone line, Z is a load of an exchange, and RET is a blockage line.

When sending dial pulses to the circuit shown in FIG. 2, the pulses are generated by turning on and off the pulse generation relay P. In this case, in order to shape the waveform of the dial pulse generated in the dial pulse generation line, the switch S is turned on and the contact is made, and the line is closed when the dial pulse is sent out by the resistor R whose resistance value is sufficiently smaller than that of the blocked wire ring RET. .

Therefore, when the sending of the dial pulse is completed and the switch S is turned off and the contact is released, a current flows through the blocking wire RET, resulting in a large change in the current from when sending out the pulse.

On the other hand, since a large conductive load is connected to the line or line exchange, there is a drawback in that the above-mentioned current change may generate a back electromotive force, which may cause the exchange to malfunction.

(Objective) The object of the present invention is to provide a communication device capable of eliminating the above-mentioned drawbacks of the conventional example and preventing malfunctions of exchanges on the same line.

[Embodiment] An embodiment of the uninvented invention will be explained in detail with reference to the drawings 1-
Ru.

FIG. 1 is a circuit diagram that does not show the configuration of this embodiment.

In Fig. 1, 1 is a telephone, 2 is a relay for connecting the line to the tire valve circuit side or the communication device side, and 3
is a line state detection unit for detecting the line state.

"Line status detection 1" (section 3 is a circuit section that detects the presence or absence of an output signal from the line, detects the reversal of the line pole +'l-, and monitors collisions before sending out tire pulses.

4 is the line! This is a switching relay for switching the connection between - to the telephone 1 side or the 0 dialing device side.

5 is a dial pulse circuit, and RET is a blockage wire ring for holding a current line loop.

6 is a communication unit that performs communication via line I.

+Ht, switching control of the relays 2.4, and control of dial pulse transmission are all performed by an unillustrated control section of the device.

This embodiment will be explained based on the above configuration.

First, when generating dial pulses, the line is connected to the dial pulse circuit 5 by turning on relay 2 and then turning on relay 4.

Then, before sending out the dial pulse, the line status detection unit 3
Collision monitoring is performed for a predetermined period of time.At this time, the resistance value of R1 is sufficiently large, so the switch for the second line does not operate. Then, when the collision monitoring is completed, the current is determined according to the iX output tire pulse under the control of the control unit of the communication device (not shown).
It flows to the light emitting part of Kabra T2. This talented guy] Kabra T2
According to the light emitting operation of the light emitting part of the photocoupler T2, the transistor of the light receiving part of the photocoupler T2 is turned on and off, and according to the on and off of the light receiving transistor of the first photocoupler T2, the transistors 1 to T1 are turned on and off.
Or on/off and dial pulses are sent out. When the transmission of dial pulses is completed, relay 2h) is turned off and line I- is connected to the communication device side. The feature of this embodiment is that the impedance of the resistor R2' of the dial pulse circuit 5 and the transistor D is set to the blocking line Ni so that the current value does not change when the relay 2 is turned off and the line current or the cold current line RET flows. The purpose is to set it to be equivalent to the impedance of RET.

Is this possible to prevent changes in the current? In the conventional case, the resistance R2 was set to a sufficiently smaller resistance value than the blockage ring RET in order to shape the waveform of the dial pulse. In this embodiment, the dial pulse circuit 5 and the communication device (blocking wire) are selectively connected to the line by turning on the relay 2, so that the resistance value R2'
(including +-runcisor T) can be equivalent to the blockage line RET.

FIG. 3 is a circuit diagram showing another embodiment of this embodiment.

The difference between Fig. 3 and Fig. 1 is that the line status detection section 3 is provided before the relay 4, which allows only the line to be connected to the normal telephone 1.
It is important that the line state detection section 3 detects a paging signal etc. even when the line is connected to the network.

As described above, according to this embodiment, the dial pulse circuit 5 and the blockage line RET (the cold line ring RET maintains the line loop when a communication device is connected to the line) are selectively switched by the switching relay 2. Change the impedance of dial pulse circuit 5 (R2'
By making TI) equivalent to the impedance of the cold flow line RET, it is possible to prevent changes in current that occur when the line is connected to the communication device side.

Note that the dial pulse circuit 5 of this embodiment is an example,
Any dial pulse generating circuit may be used as long as the impedance of the dial pulse circuit is set to be equivalent to the impedance of the obstructing wire.

In addition, this embodiment automatically generates a dial pulse, sends the dial pulse to the line, forms a loop, and performs lI!
A communication device that performs I-communications, such as a telephone with an automatic calling function,
This can be applied to all communication devices such as facsimile machines and telex machines.

(Effects) As explained above, the present invention can prevent malfunctions of line exchanges.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the structure of a tree embodiment, FIG. 2 is a diagram showing a conventional example, and FIG. 3 is a circuit diagram showing a structure of another embodiment. 1 is a telephone, 2.4 is a relay, 3 is a line status detector, 5
is the Atial pulse circuit, and RET is the blockage line.

Claims (1)

[Scope of Claims] Sending means for automatically sending a dial signal to a line, holding means for holding a line loop, switching means for selectively connecting the sending means and the holding means to the line. A communication device characterized in that the impedance of the sending means and the impedance of the holding means are made equal.