JPS5952862B2 - intercom device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called parent-child type intercom device that is composed of one base unit and two slave units.

In all commonly used parent-child intercom devices, when a call is received from each handset to the base unit, there is an indicator lamp indicating this, and based on the display of this indicator lamp, the caller receives a call from each handset. This device is equipped with a selection changeover switch to form a communication path between the parent and child, and when forming a communication path between the parent and child, the display lamp indicates which handset received the call each time. After confirming this, it was necessary to operate the selection changeover switch to the side of the handset that received the call, and to form a communication path between the parent and child.

Therefore, in this type of intercom device, as the number of handsets increases and the number of display lamps and selection switches increases accordingly, it becomes extremely difficult to check which handset received a call. There was a problem that it became complicated and the operation of the selection changeover switch became troublesome. The present invention eliminates the above-mentioned conventional drawbacks, and has a simple configuration. When a call is received from a slave unit, the call is accurately transmitted to the base unit, and the base unit simply makes a call and switches the call. It is an object of the present invention to provide an excellent intercom device capable of forming a communication path between the base unit and the called slave unit simply by switching the switch to the call side.

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

The figure is an electrical connection diagram of one embodiment of the intercom device of the present invention. In the figure, 1 is a calling circuit that constitutes the base unit, 2 is a channel selection circuit that also constitutes the base unit, and 3 and 4 are They are the first and second slave devices, respectively. In addition, the calling circuit 1
, E is the power supply, SPI is the speaker for ringing sound emission,
OSC is an oscillation circuit for ringing tone generation, SW is an oscillation circuit O
A switching control circuit that controls the SC, M is a microphone for talking, A is an amplifier circuit that amplifies the signal from the microphone M, R is a speaker for talking, HYB is a hybrid circuit, and 5 is a switching circuit for calling and calling. This is a call/call switching switch.

In the channel selection circuit, T, -T4 are respective transistors forming a switching circuit which is controlled on/off by the calling signals from the handsets 3 and 4, and RRY is the transistor T forming the switching circuit.

,T. Windings CL, CL connected in series to each of
. RS is a changeover switch for switching communication paths driven by latching relay RRY, and Dl and D2 are each winding CLl of latching relay RRY.
, CL2 are respectively connected in parallel, R1 to R8 are resistors, Cl and C2 are bypass capacitors, and D3 is a diode. Further, in handsets 3 and 4, M is a miter for telephone calls, HYB2 and HYB3 are hybrid circuits, and S2 and S3 are call switches.

In the above embodiment, in the steady state, the bases of the transistors Tl and T4 constituting the channel selection circuit 2 are connected to the resistors Rl, R2,
A predetermined bias voltage is applied via R5 and R6, and the transistors Tl and T4 are in an on state.

Therefore, in this state, the transistors T2 and T3 are in an off state, and no current flows through the first and second windings CL1 and CL2 constituting the latching relay RRY. Now, assume that the call switch S2 in the first handset 3 is turned on. When the calling switch S2 is turned on, the calling switch S2 substantially short-circuits the terminals 1L1 and IL2, and the base potential of the transistor T4 becomes substantially equal to the emitter potential. Therefore, in this state, transistor T4 is turned off and transistor T3 is turned on. When the transistor T3 is turned on, one winding C constituting the latching relay RRY is connected through the transistor T3.
A predetermined current flows through L2, and the changeover switch RS switches to the terminal Ra.
It is thrown into the side. Then, the changeover switch RS is connected to the terminal Ra.
When the switch is turned on, the call switch S2 and the changeover switch R are activated.
A predetermined calling signal (negative signal) is applied to the switching control circuit SW via the calling changeover switch S1, and the switching control circuit SWl drives the oscillation circuit 0SC for generating a ringing tone. Therefore, in this state, the oscillation circuit 0SC generates a predetermined ring tone, and the speaker SPl outputs the predetermined ring tone. Note that when the output switch S2 is turned off, a predetermined ringing signal (negative signal) is no longer applied to the switching control circuit SWl, and no ringing tone is output from the speaker SPl.

That is, the ring tone is output from the speaker SP1 only while the ring switch S2 is turned on. Furthermore, when the calling switch S2 is turned off, the transistor T4 is turned on and the transistor T3 is turned off, but the latching relay RRY itself remains in its previous state.

That is, when the call switch S2 is turned off, the current flowing through one winding CL2 of the latching relay RRY is cut off by the action of the transistor T3, but the latching relay RRY itself does not turn off the changeover switch RS in this state. The switch RS is configured not to be driven, and therefore the changeover switch RS remains connected to the terminal Ra side. In this way, when the call switch S2 is turned on,
The changeover switch RS is turned on to the terminal Ra side, and the speaker S
Since the ring tone is emitted from Pl, the speaker S on the main unit side
Hear the ringing tone from Pl, and turn the call switch S1.
By simply inserting the
A conversation can be started between the calling handset 3 and the base unit via the RS.

Next, a case will be described in which a call is received from the second handset 4 while the base unit is communicating with the first handset 3.

In this case, a positive voltage proportional to the input/output impedance of the hybrid circuit HYBl is applied to the base of the transistor T1, which should be turned off when the calling switch S3 of the handset 4 is turned on, via the diode D3 and the resistor R7. Therefore, even if the call switch S3 is turned on, the transistor T1 is not turned off. Therefore, the transistor T2 is turned on, current flows through the other winding CLl of the latch relay RRY, and the changeover switch RS is never switched to the terminal Rb side, and no interrupts from the slave unit 4 are allowed. Become. Note that when the call between the base unit and the slave unit ends and the calling call changeover switch S1 is turned on to the calling side terminal a, the positive voltage applied to the base of the transistor T1 changes to the switching control circuit SWl. It becomes substantially lower in proportion to the input impedance of the second handset 4, and a call from the second handset 4 can be responded to in the same way as a call from the first handset 3.

As is clear from the above embodiments, according to the present invention, when there is a call from the handset and a ring tone is emitted from the base unit, all that is required is to hear the call and simply turn the call switch to the terminal on the calling side. You can start a call with the handset that made the call, and there is no need to check which handset made the call each time and operate the selection button corresponding to that handset. has the advantage of being extremely simple.

Although not specifically explained in the embodiment, the calling/calling switch S1 is automatically switched to the calling side and the calling side in conjunction with lifting and lifting of the handset equipped with the calling microphone M1 and the speaker R, respectively. In this case, the base unit can now respond to calls from the handset by simply lifting the handset, and no other operations are required. has advantages.

[Brief explanation of the drawing]

The figure is an electrical wiring diagram of one embodiment of the intercom device of the present invention. 1... Calling circuit of base unit, 2...
Tuning circuit of main unit, 3, 4...Slave unit.

Claims (1)

[Claims] 1 Equipped with one base unit and two slave units, and when the respective call switches on each slave unit are operated, there are multiple switching circuits that operate in response to the operation, and the output of these switching circuits. a latch relay that is driven by the above, and switches a changeover switch that switches the communication path between the base unit and the slave unit to the slave unit that receives the call;
An intercom device comprising a call/call changeover switch that switches and transmits a call signal and a call signal from a handset transmitted via the call path to a call circuit and a call circuit, respectively.