JPH0537592Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a circuit for supplying power for internal telephone calls used in a button telephone device.

[Conventional technology]

A button telephone device is composed of a main device and a plurality of button telephones (hereinafter referred to as handsets), and generally the main device and each handset are connected by a pair of speech lines and a signal line, and the signal line is connected to the main device and each handset. In addition to transmitting and receiving control data from the main unit and operation data from each slave unit through the main unit, various controls necessary for exchange connections are performed, and power is supplied from the main unit to the telephone line for internal telephone calls. This allows extension calls to be made between handsets.

In addition, in each handset, a transformer is connected as a bridge in order to amplify the audio signal from the telephone line and emit it from the speaker when in the on-hook state.
Through this, the ring tone, hold tone, or voice signal at the time of a voice call sent from the main device to the telephone line is picked up and emitted from the speaker.

An example of such a button telephone device is disclosed in Japanese Patent Application Laid-Open No. 59-158191, which was filed separately by the present applicant.
Details are disclosed in the publication.

[Problem that the invention attempts to solve]

However, in the past, power for internal calls was always supplied from the main unit, and in each slave unit, the transformer was connected to the call line as a bridge even in the on-hook state, and a relay contact for private calls was connected to the call line. Even if a
Since direct current flows to the next winding, current flows from the power supply circuit for talking even when there is no call, and especially when calling all at once, current flows to each handset at the same time. Impedance elements such as transformers provided in the supply circuit generate heat, causing a rise in temperature within the main device, and also cause problems such as excessive power consumption and uneconomical use.

[Means for solving problems]

In order to solve the above-mentioned problem, the present invention is constructed by the following means.

That is, in the above-mentioned button telephone device, an impedance element connected to a common communication line and exhibiting high impedance to voice signals from the common communication line, and a switching element connected in series with this impedance element are connected to the main device. The extension line power supply circuit is equipped with a switching device that turns on a switching element when at least one of the above-mentioned button telephones is set to transmit an extension voice signal to a common communication line, and connects the extension line to the common communication line via an impedance element. The main unit is equipped with a control unit that supplies power for internal calls.

[Effect]

Therefore, when one of the handsets sends an audio signal to the communication line during a call or a voice call, the switching element is turned on, and power for the call is supplied via the impedance element, so it is not possible to use it under unnecessary conditions. Power will not be supplied.

〔Example〕

Hereinafter, details of the present invention will be explained with reference to figures showing embodiments.

Figure 2 shows the main device of the button telephone device (hereinafter referred to as
KSU) 1, which accommodates a telephone line from a central office line or a private branch exchange as an outside line 2, a signal sending circuit (hereinafter referred to as SSC) 3, and a switching relay L between the outside line circuit and the extension circuit. It is connected to a communication line 4 with a button telephone (hereinafter referred to as a slave unit), which is omitted in the figure, via a contact point L, and a switching relay L is housed in a monitoring circuit (hereinafter referred to as SUP) 5, and it is possible to make a call by operation. Connect line 4 to the internal power supply circuit (hereinafter referred to as IPC)
On the other hand, depending on restoration, the communication line 4 may be connected to the circuit on the outside line 2 side.

In addition, for SSC3, a pulse generation circuit (hereinafter referred to as PDG) that generates a dial signal of a pulse signal
7. MF generation circuit (hereinafter referred to as MFG) that generates a dial signal of composite audio frequency (hereinafter referred to as MF) signal 8.
The outputs of a hold tone generating circuit (hereinafter referred to as HTG) 9 which generates a melody etc. for hold tone are given to the outside line 2 side of contact 1, and an incoming call detection circuit (hereinafter referred to as HTG) which detects a ringing signal RDT) 10 is connected as a bridge, while a ringing tone generation circuit (hereinafter referred to as CTG) 11 is provided which generates various ringing tones for the handset.The output of this and the output of HTG9 is connected to a tone amplifier (hereinafter referred to as , TA) 12 and then sent to each slave device via the IPF 6.

In addition, a control unit (hereinafter referred to as CNT) consisting of a processor such as a microprocessor and memory, etc.
13 is provided, and the power supply circuit (hereinafter referred to as PFD)
14, as well as a transmitter/receiver circuit (hereinafter referred to as
SRC) 15, power is supplied to the signal line 16 to each slave unit, and at the same time, control data is transmitted and operation data is received from the slave unit, and the operation data and, R.D.T.
Make control decisions according to the detection power of 10,
SSC3, PDG7~HTG9, CTG11, IPF6,
It controls the SUP 5, etc., and controls each slave device by transmitting control data.

The main power source is AC commercial power, which is rectified and stabilized by the power supply circuit (hereinafter referred to as PS) 17, and then converted into local power supplies of +24V, +12V, and +5V, which are supplied to each part where they are needed. The SUP5 monitors this voltage and gives a reset signal to the CNT13 via the reset circuit (hereinafter referred to as RES) 18 in response to the turning on and off of the main power AC.
is initializing and stopping operation.

On the other hand, a plurality of handsets connected in parallel to the communication line 4 and the signal line 16 each have a CNT 13 and a
Equipped with a circuit similar to the SRC15, these are operated by a power supply via the signal line 16, and when operations such as off-hook, on-hook, selection of an outside line or extension, dialing, etc. are performed, these operation data are transmitted as a signal. Upon receiving control data from KSU1 as well as being transmitted over line 16,
In response to this, the loudspeaker amplifier is turned on and off, each indicator light is turned on and off, and the confidential communication relay with a contact inserted into the communication line 4 side is operated and restored.

Therefore, when any handset performs an off-hook operation or a call operation to outside line 2, CNT13 of KSU1 restores contact l and sends a pulse or MF dial signal to control PDG7 or MFG8 and SSC3. is sent, and depending on the other party's response, you can freely talk using the handset.

Also, if there is an incoming call from outside line 2, RDT10
CNT13 maintains contact 1 in the operating state according to the detection power of
Since the ring tone is sent out via the IPF 6 and the communication line 4, the speaker of each slave unit sounds to notify the incoming call, and the CNT 1 responds to any off-hook.
3 restores the contact 1, a response call is made by the handset that has gone off-hook.

On the other hand, in an internal call between handsets, contact l is in the operating state, and CTG11 and TA are in the operating state.
12, a ringing tone is transmitted, and in response to the response of the called handset, power for communication is supplied from the IPF 6, and an extension conversation is performed.

In addition, since it is equipped with PDG7 and MFG8,
For example, by making a call using a pulse dial signal and then transmitting an MF signal after the other party responds, it becomes possible to receive services such as automatic account balance reporting from a bank or the like in response to the MF signal.

In addition, in each handset, a relay contact and a hook switch for confidential communication are sequentially inserted from the call line 4 side between the call line 4 and the call circuit having the handset, and when the handset is in the on-hook state, the touch switch and The primary winding of the transformer is bridge-connected through a parallel circuit of a capacitor and a resistor, which picks up the audio signal, amplifies it with a loudspeaker amplifier, and then drives the speaker. However, the relay contact is turned on when sending out ringing and hold music, and when making a call, and in the on-hook state, the ring tone, hold music, or incoming voice is emitted from the speaker, and in the off-hook state, a call is made using the handset. ing.

On the other hand, the relay contact is normally off, a confidential state is set, and it is impossible to listen to other call voices.

FIG. 1 is a circuit diagram of the IPF 6, in which the primary winding P ₁ of the transformer T 1 used as an impedance element is connected in series to the communication lines 4 a and 4 b connected to each handset via the contact l _. ,P ₂ is inserted,
On the neutral side of this, the power supply +12V and
A power supply return path is connected via a transistor Q ₁ as a switching element, and a capacitor C ₁ for the audio signal path is connected between the neutral point sides of the primary windings P ₁ and P ₂ .
A diode _D1 used for absorbing surges when current is cut off is connected, and the output of TA12 is applied to the secondary winding S of the transformer _T1 .

Also, transistor Q ₁ is connected through resistor R ₁
A control signal S _C is given from the CNT 13, and this signal is used during an internal call between handsets, during an extension call between a doorbell and a handset (not shown in Fig. 2), and when any handset calls another handset. Only when making an individual voice call or a simultaneous voice call to the machine, the control signal S _C becomes "H" (high level), and accordingly, the transistor Q ₁ turns on, and the power supply for communication to the communication lines 4a and 4b is turned on. Supply has become a necessity.

In response to the above, a hold tone and a ring tone are provided from the TA 12, and this is transmitted to the communication line _4a , via the transformer T1.
When sent to 4b, the control signal S _C is “L”
(low level), transistor _Q1 remains off, and the power supply +12V is applied to communication lines 4a and 4b.
No current flows through the terminal, and power is not supplied.

Therefore, each handset is in an on-hook state,
A transformer for picking up audio signals is connected to the communication line 4a,
4b, and as a result, even if DC is flowing, transistor _Q1 is off except when an audio signal is sent from one of the slave units, and no power is supplied to the transformer. Heat generation due to excessive energization of the primary windings P ₁ and P ₂ of T ₁ and ineffective consumption of power are prevented.

Also, during an extension call or voice call, call line 4
Each slave unit is connected in parallel to a and 4b, but 1
Since the next windings P ₁ and P ₂ present a high impedance to the audio signal, the audio signal is transmitted and received between each handset with low loss.

Note that the capacitor _C2 is for bypassing noise components. However, in place of the transformer _T1 , a blockage wire, a high impedance circuit made of a semiconductor, etc. may be used, and the same effect can be obtained by using another switching element in place of the transistor _Q1 , if these conditions are met. Accordingly, the configuration shown in FIG. 1 can be arbitrarily selected and various modifications can be made.

[Effect of idea]

As is clear from the above explanation, according to the present invention, power for internal calls is supplied only when necessary, and unnecessary heat generation and excessive power consumption of the impedance element provided in the power supply circuit are prevented. Great effects can be obtained in various button telephone devices.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, with Fig. 1 being a circuit diagram of the IPF and Fig. 2 being a block diagram of the KSU. 1...KSU (main unit), 4, 4a, 4b...talk line, 6...IPF (internal power supply circuit), 13...
CUT (control unit), T ₁ ... transformer (impedance element), P ₁ , P ₂ ... primary winding, Q ₁ ... transistor (switching element).

Claims (1)

[Scope of utility model registration request] Consisting of a plurality of key telephones and a main device, the main device and each of the plurality of key telephones are connected by a common communication line, and an extension line that supplies power for internal communication to the common communication line within the main device. A button telephone device equipped with a power supply circuit includes an impedance element connected to the common communication line and exhibiting high impedance to voice signals from the common communication line, and a switching element connected in series with the impedance element. the extension line power supply circuit, and turns on the switching element when at least one of the button telephones is set to send an extension voice signal to the common communication line, and transmits the audio signal via the impedance element. A button telephone device, characterized in that the main device includes a control unit that supplies power for internal telephone calls to the common telephone line.