JPH02280558A - Parent-child telephone device - Google Patents

Abstract

PURPOSE:To attain changeover between a master set and a slave set, holding and transfer via a line between the master set and the slave set by controlling a changeover switch of the master set and a slave set so that the line is connected to the master set in the standby state, controlling a DC voltage to be outputted to a slave set during talking and controlling the sets so as to hold the line when a holding key is operated during the talking. CONSTITUTION:When a hold key 52 is depressed during the talking of the master set 32, a CPU 51 brings a DP terminal to a high level and brings a level of an HC terminal to a low level to start a hold tone circuit 49. Thus, when the DP terminal reaches a high level, even when a hook switch 38 is turned off, transistors(TRs) 46, 46 are consecutively turned on and no trunk line is opened. When a call key of the master set 32 is depressed, the CPU 51 brings a level of an OSC terminal to a low level to start an oscillator 54, and the oscillator 54 generates a pulse wave with a DC voltage from an A/D converter 53 and the pulse wave is supplied to a slave set 33 via a voltage detection circuit 55 and the trunk line 36 and a ringer 60 of the slave set 33 drives a buzzer 61 to generate a call tone.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a parent-child telephone device having a private conversation function.

BACKGROUND OF THE INVENTION Since the liberalization of conventional technology communications, it has become common for ordinary households to share one line with multiple telephones; for example, in a two-story home, telephones are installed on the first and second floors, respectively.

In this case, two telephones share one line, so
Calls can be transferred and calls can be made between telephones, but calls to outside lines can be overheard by other telephones, so a secret call function has been put into practical use to prevent this.

FIG. 2 shows the configuration of a conventional parent-child telephone device.

In FIG. 2, reference numeral 21 denotes a central office exchange in which a base unit 22 and a slave unit 23 are connected in parallel via a two-wire central office line 24, and a two-wire control line 25 connects the base unit 22 and slave unit 23 in parallel. connected via. Note that power to the base unit 22 and slave unit 23 is supplied from the exchange 21 via the central office line 24.

In the above configuration, for example, a call is sent from the base unit 22 to the slave unit 23.
If you want to transfer to , press the transfer button (
(not shown) is operated, a calling signal is sent from the base unit 22 to the handset 23 via the control line 25, and the handset 23 generates a ringing tone in response to this calling signal.

Further, for example, when the base unit 22 is in a call, a signal indicating that the office line 24 is in use is sent from the base unit 22 to the slave unit 23 via the control line 25, and the slave unit 23 receives this signal. ,
The central office line 24 is configured not to be closed even when off-hook, and therefore, the telephone call between the base unit 22 and the outside line is not heard by the handset 23.

Problems to be Solved by the Invention However, in the above conventional parent-child telephone device, the control line 2
In addition to the central office line 24, a control line 25 must be installed within the dwelling unit, and therefore, wiring work for the control line 25 is required.

SUMMARY OF THE INVENTION In view of the above conventional problems, it is an object of the present invention to provide a parent-child telephone device that can simplify wiring work.

Means for Solving the Problems In order to achieve the above object, the present invention provides a hold key for placing a line on hold, a call key for calling a slave unit, a circuit for holding the line, and a circuit for placing the line on hold between the base unit and the base unit. A selector switch that selectively connects to the slave unit, a circuit that detects the voltage of the line between the base unit and the slave unit, and a DC voltage that is generated from a commercial power source and output to the line between the base unit and the slave unit. The base unit includes a circuit that generates a pulse wave using the DC voltage and outputs it to a line between the base unit and the slave unit, and a light emitting element that emits light using the DC voltage from the base unit, and a light emitting element that emits light using the DC voltage from the base unit. The slave unit is equipped with a circuit that generates a ringing tone using pulse waves from the base unit.
Controls the changeover switch so that the line is connected to the base unit during standby, controls the output of DC voltage to the handset during a call, and puts the line on hold if the hold key is operated during a call. control so that if the call key is operated while on hold, a pulse wave is output to the slave unit, and if a voltage drop in the line between the base unit and the slave unit is detected, the line is output to the slave unit. The changeover switch is controlled so that the connection is made.

Effects With the above configuration, the present invention can switch, hold, and transfer between the base unit and the slave unit via the line between the base unit and the slave unit,
Therefore, there is no need to install a separate control line between the parent device and the slave device.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the parent-child telephone device according to the present invention, and FIG. 2 is a flowchart for explaining the operation of the parent-child telephone device shown in FIG.

In FIG. 1, numeral 31 is a central office exchange to which this parent-child telephone device is connected, 32 is a base unit connected to the central office exchange 31 via two-wire central office lines 34 and 35, and 33 is a two-wire central office line. 36.
This is a slave device connected to the master device 33 via 37.

In the base unit 32, 38 is a hook switch that turns on and off when the handset of the base unit 32 is off-hook and on-hook, and 38a is a switch that is linked to the hook switch 38. The off-hook and on-hook are connected to the central processing unit (C) via an interlocking switch 38a.
PU) 51.

39.40 is a changeover switch for connecting the office line 34.35 from the central office exchange 31 to the base unit 32 side, and 41.42 is a switch for connecting the office line 34.35 to the slave unit 32 via the office line 36.37. These selector switches 39 to 42 are used as selector switches 39 to 42 when in standby mode.
0 is turned on, and the changeover switches 41 and 42 are turned off.

The changeover switches 39 and 40 are also connected to a calling ringer 43 and a buzzer 44 via a full-wave rectifier circuit, and are also connected to a PNP type transistor 4 via another full-wave rectifier circuit.
The base of the transistor 45 is connected to the collector of an NPN transistor 46,
The collector is connected to a communication circuit 47.

The emitter of transistor 45 is connected to hook switch 3.
8, and the other terminal of the hook switch 38 is connected to a transistor 46 via a diode 48a.
0 base, and is grounded via a reverse Zener diode 48b. Note that the emitter of the transistor 46 is grounded, and the cathode of the diode 48a is connected to the DP terminal of the CPU 51.

49 is a holding tone circuit which outputs a holding tone to the receiver via the telephone call circuit 47 from the control (HC terminal) K of the CPU 51;
50 is a speaker for reproducing the voice of the other party based on the voice signal from the telephone call circuit 47, and 52 is a key provided with a dial key, a hold key, a call key, etc.

53 is A for converting the AC voltage of the commercial power supply into DC voltage from the control (A/D terminal) K of the CPU 51 and supplying it to the slave unit 33 via the oscillator 54, the voltage detection circuit 55, and the office line 36. The oscillator 54 generates a pulse wave 72 for calling the handset using the control of the CPU 51 (OS C terminal) and the DC voltage from the A/D converter 53, and sends it to the voltage detection circuit 55 and the office line. The voltage detection circuit 55 detects the DC voltage between the A/D converter 53 and the slave unit 33 and outputs the detection signal to the CPU 51 .

The slave unit 33 has almost the same configuration as the base unit 32, but a light emitting diode 67 is newly connected to the central office line 36.
Changeover switches 39 to 42 of main unit 32 and A/D converter 53
, oscillator 54, and voltage detection circuit 55 are not provided.

Therefore, the ringer 60, the buzzer 61. Hook switch 62, etc., transistors 63, 64, talking circuit 65, diodes 66a, 66b, hold music circuit 67, speaker 6
8, a central processing unit (CPU) 69, and a key 70 are circuits equivalent to the above-mentioned circuits of the base unit 32, respectively. Furthermore, C.P.
The software of U69 is different as explained below.
Further, the key 70 is provided with a monitor key instead of a call key.

Next, the operation of the above embodiment will be explained with reference to FIGS. 1 and 2.

During standby, the 16Hz incoming signal (calling signal) 71 sent from the station changer 31 via the station line 34.35 is as follows:
input to the ringer 43 via the changeover switches 39 and 40,
The ringer 43 drives the buzzer 44 to generate a ringing tone (steps 101 and 102 in FIG. 2).

In response to this ringing tone, the handset of base unit 32 is taken off-hook and hook switch 38 is turned on, transistor 46 is turned on, transistor 45 is turned on, and the DC voltage from central office exchange 31 is transferred to communication circuit 47. is applied, and the state becomes ready for communication (steps 104 to 3).
106).

In this case, the switch 38 linked to the hook switch 38
a is turned on, the CPU 51 sets the A/D terminal to a low level, so that the AC voltage from the commercial power source is converted to a DC voltage by the A/D converter 53, and this DC voltage is sent to the oscillator 54 and the voltage detector. The light is supplied to the handset 33 via the circuit 55 and the central line 36, and therefore the light emitting diode 67 of the handset 33 lights up (steps 107 to 110).
The user of the handset 33 can know from this lighting that the base unit 32 is in the middle of a call.

When the hold key of the keys 52 is pressed during a call on the base unit 32, the CPU 51 sets the DP terminal to high level and the HC terminal to low level to activate the hold sound circuit 49. Therefore, when the DP terminal becomes high level, even if the hook switch 38 is turned off, the transistor 4
5.46 is on continuously and the central office line is not released (
Steps 111-114).

Next, when the call key of the base unit 32 is pressed, the CPU
51 starts the oscillator 54 by setting the O8C terminal to low level, and the oscillator 54 generates a pulse wave by the DC voltage from the A/D converter 53, and this pulse wave is transmitted to the voltage detection circuit 5.
5. The signal is supplied to the handset 33 via the central office line 36, and the ringer 60 of the handset 33 drives the buzzer 61 to generate a ringing tone (steps 115 to 118).

When the handset of handset 33 is taken off-hook in response to the ringing tone, and hook switch 62 is turned on, transistor 64 is turned on, and therefore transistor 63 is turned on. As a result, the voltage of the office line 36 decreases and the main unit 3
2, the CPU 51 controls the changeover switches 39 to 41 so that the office line 34.35 is connected to the slave unit 33 via the office line 36.37, and The driving of the A/D converter 53 and oscillator 54 is stopped.

Therefore, the main unit 32 is disconnected from the central office lines 34 and 35, and the direct current voltage from the one-office exchange 31 is transferred to the communication circuit 4.
7 is applied, and a call becomes possible (step 11).
9-122).

Therefore, according to the above embodiment, the changeover switches 39 to
41 and the light emitting diode 67, it is possible to maintain the confidentiality of the base unit 32, and the pulse wave from the oscillator 53 of the base unit 32 is sent to the ringer 60 of the slave unit 33 via the central line 36.
By supplying the buzzer 61, calls from the main unit 32 are transferred to the slave unit 33, so there is no need to install a control line inside the dwelling unit in addition to the central office lines 36 and 37, which simplifies wiring work. be able to.

As described in detail, the present invention includes a hold key for placing a line on hold, a call key for calling a handset, a circuit for holding the line, and a circuit for selectively placing the line on a base or handset. a circuit that detects the voltage of the line between the base unit and slave unit, a circuit that generates DC voltage from a commercial power source and outputs it to the line between the base unit and slave unit, and a circuit that detects the voltage of the line between the base unit and slave unit, The base unit is equipped with a circuit that generates pulse waves using voltage and outputs them to the line between the base unit and the slave unit, and also includes a light emitting element that emits light using the DC voltage from the base unit, and a circuit that generates pulse waves from the base unit. The handset is equipped with a circuit that generates a ringing tone, and the base unit controls a changeover switch so that the line is connected to the base unit during standby, and outputs DC voltage to the slave unit during a call. , controls to put the line on hold if the hold key is operated during a call, outputs a pulse wave to the handset when the call key is operated while on hold, and controls the connection between the base unit and handset. The changeover switch is controlled so that the line is connected to the slave unit when a voltage drop is detected in the line between the base unit and the slave unit. Switching, holding, and transferring can be performed.Therefore, there is no need to install a separate control line between the agricultural machine and the slave machine, which simplifies the wiring work.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the parent-child telephone device according to the present invention, FIG. 2 is a flowchart for explaining the operation of the parent-child telephone device of FIG. 1, and FIG. 3 is a conventional parent-child telephone device. FIG. 2 is a block diagram showing a telephone device. 32...Base unit, 33...Slave unit, 34-37...Station line, 39-42...Selector switch, 43.60...
Ringer, 44.65... Buzzer 45, 46... Transistor (holding circuit), 51... Central processing unit (CP
U), 52... Key, 53... A/D converter (DC voltage generation circuit), 54... Oscillator (pulse generation circuit)
, 55... Voltage detection circuit, 67... Light emitting diode. Figure 81

Claims (1)

[Claims] A hold key for putting the line on hold, a call key for calling the handset, a circuit for holding the line, a changeover switch for selectively connecting the line to the base unit or the handset, and a switch for connecting the line to the base unit or the handset. A circuit that detects the voltage of the line between the base unit and the slave unit, a circuit that generates a DC voltage from a commercial power source and outputs it to the line between the base unit and the slave unit, and a circuit that generates a pulse wave from the DC voltage and connects the base unit and the slave unit. The base unit is equipped with a circuit that outputs to a line between the base unit, and the slave unit is equipped with a light emitting element that emits light based on the DC voltage from the base unit, and a circuit that generates a ring tone using the pulse wave from the base unit, The base unit controls the changeover switch so that the line is connected to the base unit during standby, and controls the DC voltage to be output to the slave unit during a call, and when a hold button is operated during a call. control to put the line on hold, control to output a pulse wave to the handset when the call key is operated while on hold, and detect voltage drop in the line between the base unit and the handset. 1. A parent-child telephone device, characterized in that the changeover switch is controlled so that the line is connected to the handset when the telephone line is connected to the handset.