JP2581790B2 - Switching device for off-talk communication service demonstration - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a switching device for off-talk communication service demonstration.

There is known a so-called off-talk communication service in which a signal such as music is transmitted from a center device on the station side to a subscriber using a telephone line to provide a service when the telephone line is not used for a call (at the time of off-talk). To sell such an off-talk communication service device to a customer (subscriber),
Some demonstrations may be needed.

The present invention relates to an off-talk communication service / demonstration switching device that enables a customer (subscriber) to easily perform such a demonstration.

[Conventional technology]

FIG. 3 is a diagram showing a system configuration of an off-talk communication service. In the figure, 1 is a subscriber's home, 2 is a telephone office, 3 is an information providing center, 4 is a telephone line, 5 is a center line, 11 is a home telephone, 13 is a speaker, and 12 is a signal for off-talk to a speaker or the like. An in-home connecting device for outputting, 22 is a telephone exchange, 21 is an intra-office connecting device for controlling connection between the center line 5 and the telephone line 4, and 31 is a center device such as a broadcasting facility.

In a state where the telephone 11 of the subscriber home 1 is not used for a call (off-talk state), since the center line 5 and the telephone line 4 are connected by the intra-office connecting device 21, the center device 31 of the information providing center 3 Is transmitted to the telephone line 4 and output to the speaker 13 via the home connection device 12 of the subscriber home 1. When the telephone 11 at the subscriber's home makes a call by going off-hook, or the telephone 11
When the incoming call signal is transmitted to the office, the intra-office connecting device 21 releases the connection between the center line 5 and the telephone line 4 and enables the telephone 11 to talk.

Thus, the off-talk communication service is provided from the station side to the subscriber.

[Problems to be solved by the invention]

In order to sell the off-talk communication service device to a customer (subscriber), the customer (subscriber)
As shown in Fig. 3, if the demonstration is performed, the telephone office is involved and it is necessary to cooperate with the telephone office at the subscriber's house, so the procedure is complicated, and the service for the demonstration is also required. Since the communication contents are determined depending on the center device prepared at the central office, there is a drawback that a demonstration of the communication contents suitable for the customer cannot be performed.

An object of the present invention is to provide a demonstration of an off-talk communication service device at a subscriber's house without having to cooperate with a central office, and the contents of service communication used for the demonstration are not related to the central office. Another object of the present invention is to provide an off-talk communication service / demonstration switching device that can freely select an appropriate one for the customer and easily realize a demonstration effective for achieving a purpose such as sales.

[Means for solving the problem]

To achieve the above object, according to the present invention, a first terminal connected to a telephone line, a second terminal connected to a home connection device, a third terminal connected to a pseudo center device,
A photocoupler that detects when a call current flows in a circuit between the first terminal and the second terminal and operates when the current flows;
A low-pass filter connected in series to a circuit through which a call current flows between the second terminal and the second terminal and the second terminal and the second terminal; Disconnecting the connection between the second terminal and the third terminal when the photocoupler is not operating, opening the bypass circuit of the low-pass filter to enable the low-pass filter. And a switching circuit for off-talk communication service demonstration.

[Action]

Such a switching device is brought into a subscriber's home as a consumer, a first terminal is connected to a telephone line, a second terminal is connected to a home connection device, and a third terminal is arbitrarily set to be a pseudo center device. Connect to a cassette tape recorder etc. that you have selected and brought. Then, during a call, a call current flows through a circuit between the first terminal and the second terminal, whereby the photocoupler operates and the relay circuit operates. Therefore, the low-pass filter is bypassed and invalidated, and the second terminal and the second terminal are connected to each other. Since the circuit connecting to the third terminal is disconnected, the call is performed normally.

On the other hand, when a call is not being made, a call current does not flow in a circuit between the first terminal and the second terminal, so that the photocoupler becomes inoperative and the bypass circuit of the low-pass filter is opened to enable the low-pass filter. Along with
A connection is made between the second terminal and the third terminal. Therefore, a demonstration signal from the pseudo center device is sent from the third terminal to the home connection device through the second terminal, and is further output to the speaker, thereby realizing a demonstration of the off-talk service. In addition, at this time, the high-frequency signal included in the demonstration signal from the pseudo center device is blocked by the low-pass filter and is not transmitted to the exchange.

〔Example〕

FIG. 1 is an explanatory diagram showing a method of using a switching device for off-talk communication service demonstration as one embodiment of the present invention.

3, the same components as those in FIG. 3 are denoted by the same reference numerals. 310 is a switching device for off-talk communication service demonstration according to the present invention,
320 is a pseudo center device such as a tape recorder, 111 is a terminal terminal connected to the home connection device 12 side of the demonstration switching device 310, 112 is a center input terminal connected to the pseudo center device side of the demonstration switching device 310, 113 is a line terminal connected to the telephone line side of the demonstration switching device 310.

FIG. 2 is a circuit diagram showing a switching device for off-talk communication service demonstration as one embodiment of the present invention.

In the figure, R1, R2, R3, R4 are resistors, C1, C2, C3, C4
Is a capacitor, Tr1 and Tr2 are transistors, L1 is a coil, 1
An A relay 21 controls opening and closing of the switches a1 and a2. The capacitors C2 and C3 form a low-pass filter 151 in combination with the coil L1, and cut a high-frequency signal included in the off-talk service signal from the pseudo center device 320. Also, PC is a photocoupler, 14 is a limiter, 131 is a power terminal,
It is.

 The circuit operation will be described with reference to FIGS.

When the telephone 11 at the subscriber's home is not being used for a call (off-talk state), the telephone exchange 22
Photocoupler PC is off because no current flows through
The DC voltage supplied from the DC power supply terminal 131 includes resistors R1, R
2, the voltage is divided by R3, R4 to a potential sufficient to operate the transistor Tr1, and is input to the base terminal of the transistor Tr1.

When the transistor Tr1 is turned on by this potential, the transistor Tr2 is also turned on next, and as a result, the power supply terminal 1
A current flows from 31 to the ground on the emitter side of the transistor Tr2 through the relay 121 and the transistors Tr1 and Tr2, and the relay 121 operates.

Therefore, the switch a1 in the relay 121 is released (turned off), and the switch a2 is closed and becomes conductive. Thereby, the pseudo center device connected to the center input terminal 112 is connected to the terminal terminal 111.
And an off-talk service signal for demonstration of music or the like transmitted from the pseudo center device is transmitted from the terminal terminal 111 and output from the speaker 13 via the home connection device 12.

The limiter 141 is for preventing a high voltage from being applied to the telephone line. In addition, the demonstration off-talk service signal transmitted from the pseudo center device, the high-frequency component contained therein is cut by the low-pass filter 151 configured by the coil L1, the capacitors C2 and C3, and therefore, via the line terminal 113. No high-frequency signal flows to the exchange 22. In order to satisfy the specified value in the telephone line, this low-pass filter 15
Although it is necessary to cut at least the high-frequency component of 4 kHz or more in step 1, a filter having a characteristic of passing only the DC component may be used.

Next, when the telephone 11 of the subscriber's home 1 is used for a call (off-hook state), a DC current flows from the telephone exchange 22 to the telephone line 4, and this DC current passes through a low-pass filter, so that the photocoupler PC is switched off. And the DC voltage from the power supply terminal 131 drops because a current flows to the ground through the resistor R1 and the photocoupler PC, and the resistors R1, R2, R
3. The voltage is divided by R4 to a voltage at which the transistor Tr1 cannot operate, and is input to the base terminal of the transistor Tr1.

As a result, the transistor Tr1 is turned off and then Tr2 is also turned off, so that no current flows from the DC power supply terminal 131 to the relay 121, and the relay 121 does not operate. Therefore, the switch a1 in the relay 121 is turned on and a2 is opened. This allows the terminal side terminal
The terminal 111 is disconnected from the center input terminal 112 and is connected only to the line terminal 113, so that the telephone 11 is connected only to the telephone exchange 22 to enable a telephone call. When the switch a1 is turned on, the call signal can reach the telephone by bypassing the low-pass filter 151.

As described above, in the present invention, since the telephone line and the on / off control unit of the relay 121 are connected using the photocoupler, the on / off control unit of the relay 121 is electrically connected to the telephone line. It is separated and the off-talk service can be easily demonstrated without lowering the impedance of the telephone line.

〔The invention's effect〕

As described above, according to the present invention, a simple demonstration switching circuit including two transistors, a photocoupler, and a relay can easily perform a demonstration of off-talk service communication at a subscriber's house regardless of a telephone station. There is an advantage.

In addition, since a tape recorder or the like to be a pseudo center device can be selected on the subscriber side and connected at the subscriber's house, there is an effect that a demonstration of appropriate service contents can be performed.

Further, since a relay control unit as a control unit of a switch for switching between a line leading to the pseudo center device and a telephone line is electrically separated from the telephone line by a photocoupler, off-talk can be performed without lowering the impedance of the telephone line. There is also an advantage that a service communication demonstration can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a demonstration using one embodiment of the present invention, FIG. 2 is a circuit diagram showing one embodiment of the present invention, and FIG. 3 is a system configuration diagram of an off-talk communication service. EXPLANATION OF SYMBOLS 310: Switching device for off-talk communication service demonstration, 111: Terminal side terminal, 112: Center input terminal, 113: Line terminal, 121: Relay, 151: Low-pass filter

Claims (1)

(57) [Claims] A first terminal connected to a telephone line, a second terminal connected to a home connection device, a third terminal connected to a pseudo center device, and a first terminal connected to the first terminal and a second terminal. A photocoupler which detects and operates when a call current flows through the circuit of the above, and which is deactivated when it does not flow, and a circuit through which the call current flows between the first terminal and the second terminal A low-pass filter connected in series to
When the photocoupler operates, the low-pass filter bypass circuit is closed by closing the low-pass filter, and the connection between the second terminal and the third terminal is disconnected. A switching circuit for off-talk communication service demonstration, comprising: a relay circuit for opening the bypass circuit to enable the low-pass filter and connecting between the second terminal and the third terminal.