JPH0783411B2 - Interphone device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intercom apparatus for operating a lighting slave unit using a light emitting diode.

2. Description of the Related Art Conventionally, in this type of intercom device, in order to light the light emitting diode for illumination of the intercom slave unit, another wiring is provided in addition to the wiring for normal call communication.

Problems to be Solved by the Invention However, in the above-described conventional example, there is an inconvenience that a new wiring work variation is required when the interphone device is replaced with another one because of the large number of wires.

The present invention is to solve such a conventional problem, and to provide a circuit that does not require a change in wiring work, does not cause a malfunction of the calling circuit and does not deteriorate the characteristics of the communication circuit, and that can perform a stable operation with good quality. It is what constitutes.

Means for Solving the Problems In order to achieve the above object, the present invention oscillates a call loop connected between a master unit and a slave unit and an AC signal stored in the master unit and out of a call band. Then, an oscillation circuit for sending to the call loop, a bandpass filter housed in the slave unit, for inputting the signal of the call loop and extracting an AC signal outside the call band by a filter, and a bandpass filter of this bandpass filter. A matching transformer for inputting an output signal, matching the impedance of the communication loop, and lighting the lighting means by the output signal is provided.

Action The present invention has the following effects due to the above configuration.

(1) Simply attach the oscillator circuit to the base unit, and attach the bandpass filter and matching transformer to the handset unit.
Since it is not necessary to change the wiring work, it is possible to easily attach the lighting means to the child device.

(2) Since the matching transformer is attached to the slave unit, high-quality and stable operation can be performed without causing malfunction of the calling circuit or deterioration of characteristics with the calling circuit.

Embodiment FIG. 1 shows an embodiment of the present invention.

In the figure, 1 is a master unit, 2 is a slave unit, 3 is a communication circuit of the master unit, 4 is a calling circuit, and 5 is a communication circuit of the slave unit.

Next, the operation of the above embodiment will be described. In the above embodiment, when the calling switch CS ₁ of the handset 2 is closed now, the calling circuit 4 of the base unit 1 operates and the ringing tone sounds from the speaker SP ₁ . Base unit 1 picks up the handset and hook switch H.
When S ₁ and HS ₂ are switched, the call circuit 3 of the base unit 1 and the call circuit 5 of the handset 2 are connected to form a call loop between the base unit and the handset.

In these circuits, on the base unit 1 side, an oscillator OSC _{1 having} a frequency outside the communication band, which is constantly driven by a DC power supply, transmits a transmission signal through a matching transformer T ₁ and band pass filters L ₁ and C ₁ to the handset 2 side. Is transmitted to the light emitting diode LED ₁ through the band pass filters L ₂ and C _{2 of} the slave unit 2 and the matching transformer T ₂ and is detected and the LED ₁ is turned on.

Therefore, according to the present embodiment, since the signal for lighting the light emitting diode LED ₁ is an AC signal outside the call band, the calling signal and the call signal are reliably distinguished from each other and do not affect each other such as malfunction. .

EFFECTS OF THE INVENTION The present invention has the following effects, as is apparent from the above-described embodiments.

(1) Simply attach the oscillator circuit to the base unit, and attach the bandpass filter and matching transformer to the handset unit.
Since it is not necessary to change the wiring work, it is possible to easily attach the lighting means to the child device.

(2) Since the matching transformer is attached to the slave unit, high-quality and stable operation can be performed without malfunction of the calling circuit or deterioration of the characteristics of the calling circuit.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an intercom apparatus according to an embodiment of the present invention. 1 ... Parent unit, 2 ... Slave unit, 3,5 ... Call circuit, 4 ... Call circuit, OSC ₁ ... Out-of-band oscillator, T ₁ , T ₂ ...... Matching transformer, C ₁ , L ₁ and C ₂ , L ₂ …… Bandpass filter.

Claims (1)

[Claims] 1. A call loop connected between a master unit and a slave unit, an oscillating circuit which is housed in the master unit, oscillates an AC signal outside the call band, and sends out to the call loop, and the slave unit. A band-pass filter that is housed in a machine and that receives the call loop signal and extracts the AC signal outside the call band by a filter, and the output signal of this band pass filter that is input to match the call loop impedance. And an intercom device including a matching transformer that turns on the illumination means according to the output signal thereof.