JPH033436B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention connects a plurality of telephones in parallel to a telephone line (hereinafter referred to as a central office line) from a telephone exchange to a terminal telephone of a subscriber's telephone, so that any telephone The present invention relates to a parent-child telephone device that is capable of making calls to a central office line, responding to incoming calls, making phone calls, making secret calls, and transferring telephone calls to a central office line.

(Prior Art) Conventionally, a parent-child telephone device is known in which a plurality of telephones or telephones with additional devices are connected in a multiple manner to a subscriber's premises wiring having a plurality of connection lines including a central office line. In order to provide such a parent-child telephone device with a confidential communication function, a thyristor or the like is used in each telephone. The thyristor in the telephone that captures the office line is made conductive, forming a loop between the office line and the telephone circuit, and the thyristor in the telephone that is not capturing the office line is made non-conductive, and the telephone communication circuit of that telephone and the office line are made non-conductive. and are separated. When transferring, the transferee's telephone is operated to turn on the thyristor of the receiver's telephone to de-privacy the call.

In a method in which an AC signal is generated by operating the forwarding telephone to deconfidence, a dedicated power source such as a commercial power supply or a dry cell battery is installed in the main unit or one of multiple telephones, and each telephone is equipped with a transformer. It was exactly what I needed.

In addition, in conventional parent-child telephone devices, the hold operation and release are performed mechanically or even if electronically, as mentioned above, the device's own power source is used instead of the central office power source. .

In the case of a mechanical method, in order to receive a transfer from another transferee's phone, the transferred party must lift the handset and press a button to release the hold, and even in the case of an electronic method, the call is released from hold. Although it was possible to release a call from hold by simply lifting the handset on the telephone itself, it was not possible to release a call from hold by simply lifting the handset on a telephone other than the telephone that was placed on hold.

(Problems to be Solved by the Invention) In such a parent-child telephone device, when only one person operates the telephone, the transfer operation is extremely troublesome.

For example, if a person who has been talking by raising the handset of a telephone installed on the first floor due to an incoming call wants to continue the conversation using a telephone installed on the second floor to view materials, etc., he or she may raise the handset and receiver of the telephone installed on the first floor. I had to go to the second floor, pick up the handset of the transferred phone, return to the first floor, lower the handset of the transferred phone, and then go back to the second floor and resume communication with the central office line.
Even if you did not perform this troublesome operation and made a call using the transferred telephone on the second floor while raising the handset of the transmitting telephone on the first floor, you could not make a satisfactory call because the sensitivity decreased.

An object of the present invention is to eliminate the above-mentioned drawbacks, and to perform deprivation and other controls using DC information transmitted through the control line and the calling line using only the station power source, and to control the handset of the telephone on the transfer side or the transferred side. To provide a parent-child telephone device that uses a small semiconductor switching element and a capacitor to release a hold by only raising the phone.

(Means for solving the problem) In a parent-child telephone device configured by connecting a plurality of telephones in parallel to one central office line, each telephone is connected to two talking lines, one calling line, and one telephone line. Connect by real control wire. Inside each telephone, the voltage appearing on the telephone line is rectified and applied to the telephone line, and between these telephone lines there is a semiconductor switching element having a self-holding function, and the central office line is held by conduction between the semiconductor switching element. a DC closing circuit, a capacitor charged by conduction of the switching element, a contact of a call switch for hold transfer, a hold state display circuit, a transfer call signal generation circuit, a voltage discrimination type private conversation circuit, and It has a secret release circuit that releases the secret information of the secret information circuit.

By operating a call switch provided on a telephone connected to the central office line, the semiconductor switching element having a self-holding function is triggered and made conductive, and a hold loop is formed in the DC closing circuit to connect the central office line. Put it on hold. At the same time, a hold display circuit provided in another telephone is connected between the telephone lines via the DC connection circuit and a control line, and is activated to display a hold display.While the call switch is operating, the DC connection circuit and A transfer call signal generation circuit of another telephone is connected between the telephone lines via the call line and activated to generate a transfer call signal. When the other telephone picks up the handset, the deprivation circuit is connected between the telephone lines via the DC connection circuit and the control line and activated, thereby depriving the telephone.

Furthermore, the charged capacitor discharges due to a voltage drop across the office line due to the connection of the transferred telephone to the office line. As a result, the self-holding state of the semiconductor switching element having the self-holding function is released, and the holding state of the central office line is released.

(Operation) FIG. 1 is a system diagram of a parent-child telephone device that is an example of the present invention.

REC is a rectifier, SW is a semiconductor switching element, C is a capacitor, CNT is a control unit that disables the switching element by discharging capacitor C, and R is a resistor for configuring a DC closing circuit to hold the local line. , CK is a call switch that performs transfer, SD is a sounder that is a transfer call signal generation circuit that rings during transfer, S is a privacy circuit, SR is a deprivation circuit, and N is a communication circuit.

In this section, telephone refers to a telephone with additional equipment.

When the call switch of the transfer telephone is operated, the semiconductor switching element SW becomes conductive, and a holding loop is formed with respect to the central office line by the resistance R of the DC connection circuit. During this hold period, capacitor C is charged.

Further, the control unit CNT causes the transfer call signal generation circuit SD of all telephones to ring via the calling line _L3 , and controls the deprivation circuit SR of the other telephones via the control line _L4 .

Next, when one of the telephones picks up the handset to receive the transfer, the decryption circuit from the control line described above is activated.
The secret line circuit operates under the control of the SR, and the transferred telephone is also connected to the central office line. As a result, the inter-office line voltage drops, the capacitor C of the transfer telephone is discharged, and the semiconductor switching element SW becomes non-conductive under the control of the control unit CNT, opening the DC closed circuit. The transfer is then completed when the transfer telephone hangs up the handset. In the present invention, the above-mentioned secret call, hold and transfer all utilize the local power source, and the secret call and transfer are performed using DC information using one calling line and one control line. Therefore, the capacitor C that was charged during the hold period is discharged when the transfer is received, and the switching element SW
The circuit operation is to release the reservation by making it non-conductive.

In the present invention, since a CPU or the like is not used for hold control, no current is required from the exchange side when the central office line is released.

Embodiment FIG. 2 is a configuration diagram of a parent-child telephone device which is an embodiment of the present invention.

TEL ₁ , TEL ₂ , TEL ₃ are telephones, ADP ₁ ,
ADP ₂ and ADP ₃ are additional devices added to telephones TEL ₁ , TEL ₂ , and TEL ₃ , respectively. REC ₁ and REC ₂ are rectifiers, MOH is a hold music sending circuit, and SD displays a ring tone and generates a transfer call. sounder,
LED is a transfer indicator that lights up during a transfer call, SCR is a thyristor as an example of a semiconductor switching element with a self-holding function, _C3 is a capacitor that disables the thyristor by discharging, _CK1 ,
CK ₂ is the contact of the call switch that is operated when transferring.

Note that items having the same function are indicated by the same symbol.

Next, the operation will be explained.

Operation for making a call to a central office line Now, when the handset of telephone TEL ₁ is raised to make a call to a central office line, a switch contact (not shown) operates. As a result, the station line voltage is higher than the operating voltage of the Zener diode ZD ₁ , so the station line current flows from the transistor Q ₁ (E-B) through the Zener diode ZD, making the secret circuit transistors Q ₁ and Q ₂ conductive. Configure the following loop.

Office line connection terminal L ₁ --- Rectifier REC ₁ --- Telephone
TEL ₁ ---Transistors Q ₁ , Q ₂ --- Call switch contact CK ₁ --- Rectifier REC ₁ --- Office line connection terminal L ₂ .

Through the above-described loop, the confidential communication circuit is made conductive, and the office line communication circuit of telephone TEL ₁ is closed, resulting in the office line capture state.

In this state, another telephone, for example TEL ₃ , attempts to acquire the central office line by raising the handset and activating the switch contact. However, at this time, the line voltage between the office line connection terminals L ₁ and L ₂ has been significantly reduced by the previously acquired telephone TEL ₁ , so the Zener diode ZD ₁ in the additional device ADP ₃
does not conduct and transistor _Q1 does not operate.

Therefore, the secret circuit composed of transistors Q ₁ and Q ₂ does not conduct. Therefore, all telephones other than TEL ₁ are disconnected from the central office line.

Receiving operation When a call arrives on the central office line, when a bell signal arrives from the exchange side, the sounder SD of each of the additional devices ADP ₁ , ADP ₂ , and ADP ₃ of the telephone is connected to the central office line connecting terminal L ₁ --- capacitor C ₅ --- rectifier
REC ₂ - Sounder SD - Rectifier REC ₂ - Capacitor C ₆ - A bell signal is applied through the route of the office line connection terminal L ₂ , and each additional device provides an audible indication of the arrival of the office line.

At this time, when one of the telephones raises the handset, the confidential communication circuit made up of transistors Q ₁ and Q ₂ of the telephone with the handset raised becomes conductive, as in the case of the above-mentioned call operation to the central office line. If the handset is not lifted up, the confidential circuit of the telephone becomes non-conductive. The central office line is then routed to the telephone with the handset raised, and only this telephone can answer the incoming central telephone call.

Transfer Operation Next, an explanation will be given of an operation when transferring a call from the telephone TEL ₁ , which is in use during a telephone call to the telephone TEL ₃ , as an example.

(b) If you operate the call switch provided on the additional device ADP ₁ of telephone TEL ₁ and leave the handset up, the contacts CK ₁ and CK ₂ of the call switch will be in the state shown in Figure 2. Thyristor SCR driven to opposite state by following route
becomes conductive.

Office line connection terminal L ₁ --- Rectifier REC ₁ --- Telephone
TEL ₁ --Transistor Q ₁ , Q ₂ --Contact CK ₁ --
- Gate of thyristor SCR - Resistor R ₁₈ - Rectifier REC ₁ - Station line connection terminal L ₂ .

(Although the resistor _R15 is not listed in this route, the description will be omitted if it is considered obvious. The same shall apply hereinafter.) When the thyristor SCR is activated, the central office line is put on hold by the following loop, and the hold sound is The hold tone is sent to the central office line from the sending circuit MOH.

Office line connection terminal L ₁ --- Rectifier REC ₁ --- Hold music sending circuit MOH --- Resistor R ₁₄ --- Thyristor
SCR -- Resistor R ₁₈ -- Rectifier REC ₁ -- Station line connection terminal L ₂ .

The current flowing through resistor R ₁₈ causes transistor Q ₅
conducts and the loop below charges capacitor _C3 .

Station line connection terminal L ₁ --- Rectifier REC ₁ --- Resistor
R ₁₁ - Diode D ₁₃ - Cocapacitor C ₃ Transistor Q ₅ - Rectifier REC ₁ - Office line connection terminal L ₂ .

Further, due to the conduction of the transistor _Q5 , the transistor _Q3 of the de-pricing circuit operates after the capacitors _C1 and _C2 are charged, thus forming a loop with a lower speed, and disabling the transistor _Q1 .

Office line connection terminal L ₁ --- Rectifier REC ₁ --- Telephone
TEL ₁ ---Transistor Q ₃ ---Resistor R ₁ ---Diode D ₁ ---Transistor Q ₅ ---Rectifier REC ₁
--Station line connection terminal _L2 .

As a result of operating the above call switch, the additional device
The contact CK ₂ of ADP ₁ causes the sounder SD of the transfer side telephone and other sounders SD to ring in the following loop.

Office line connection terminal L ₁ --- (Additional device ADP ₁ ) ---
Rectifier REC ₁ ---Diode D ₁₄ --- Sounder
SD - Diode D ₁₅ - Contact CK ₂ - Diode D ₉ - Transistor Q ₅ - Rectifier REC ₁ -
- Office line connection terminal L ₂ .

Office line connection terminal L ₁ --- (Additional device ADP ₂ ,
ADP ₃ ) -- Rectifier REC ₁ -- Diode D ₁₄ --
- Sounder SD - Diode D ₁₂ - Call line L ₃
--(Additional device ADP ₁ ) --Contact CK ₂ --Diode D ₉ --Transistor Q ₅ --Rectifier REC ₁
--Station line connection terminal _L2 .

Next, return the call switch. The contact CK ₁ returns to the state shown in FIG. 2, but the transistor Q ₃ continues to operate, so the transistor Q ₁ does not operate and the secret circuit remains non-conductive.

Also, contact CK ₂ returns, so transfer telephone TEL ₁
The loop of the sounder SD on the side and the other telephones (TEL ₂ , TEL ₃ ) is opened, and the ringing stops. Note that the transfer indicator LED lights up if the transfer is in a pending state, regardless of whether contact CK ₂ is activated or not.

In addition, when telephone TEL ₁ is capturing the central office line, transistor Q ₅ is not operating even if the call switch of another telephone additional device is operated.
Unable to call a telephone whose call switch is not activated.

(b) Next, we will explain the case where the handset of telephone TEL ₃ is raised in order to respond to a transfer call. Here, the handset of the transfer telephone TEL ₁ continues to be raised. When the handset of telephone TEL ₃ is raised, the office line current flows as follows.

Office line connection terminal L ₁ --- (Additional device ADP ₃ ) ---
Rectifier REC ₁ -- Telephone TEL ₃ -- Transistor Q ₁ -- Resistor R ₁ -- Diode D ₃ -- Control line
L ₄ --- (Additional device ADP ₁ ) --- Contact CK ₂ --- Diode D ₉ --- Transistor Q ₅ --- Rectifier
REC ₁ --- Office line connection terminal L ₂ .

When the transistor Q ₁ becomes conductive through the above loop, the transistor Q ₂ also becomes conductive, forming the following loop.

Office line connection terminal L ₁ --- (Additional device ADP ₃ ) ---
Rectifier REC ₁ -- Telephone TEL ₃ -- Transistor Q ₁ , Q ₂ -- Contact CK ₁ -- Rectifier REC ₁ -- Office line connection terminal L ₂ .

By connecting this telephone TEL ₃ to the office line, the voltage between the office line connection terminals decreases.

Due to this voltage drop, the capacitor _C3 in the hold circuit of the additional device _ADP1 of the transfer side telephone starts discharging through the following route.

Capacitor C ₃ (+) -- Transistor Q ₆ (E
-B) --Resistors _R12 , _R11 --Zener diode _ZD2 --Resistor _R10 --Capacitor _C3 (-).

This discharge current makes transistor _Q6 conductive, causing base current to flow through transistor _Q7 , causing it to operate and forming the following loop.

Capacitor C ₃ (+) -- Transistor Q ₆ (E
-C) -- Transistor Q ₇ (B-E) -- Capacitor C ₃ (-).

Furthermore, the following loop is formed by the conduction of the transistor _Q7 , which reduces the voltage applied to the anode of the thyristor SCR, and makes the thyristor SCR non-conductive.

Office line connection terminal L ₁ --- (Additional device ADP ₁ ) ---
Rectifier REC ₁ --- Hold music sending circuit MOH --- Resistor R ₁₄ --- Transistor Q ₇ (C-E) --- Transistor Q ₅ --- Rectifier REC ₁ --- Office line connection terminal
_L2 .

Due to the non-conduction of the thyristor SCR, the transistor _Q5 also becomes non-conductive. This causes the base potential of transistor Q ₃ to rise and transistor Q ₃ to
becomes non-conductive, and the discharging current of the capacitor _C1 of the de-privacy circuit flows through the following route and triggers the transistor _Q1 .

Capacitor C ₁ (+) -- Transistor Q ₁ (E
-B) --Resistor R ₁ --Capacitor C ₁ (-).

As a result, the transistors Q ₁ and Q ₂ forming the privacy circuit operate, and in the following loop, the privacy of the telephone TEL ₁ is released and the telephone TEL ₁ is connected to the central office line.

Office line connection terminal L ₁ --- (Additional device ADP ₁ ) ---
Rectifier REC ₁ -- Telephone TEL ₁ -- Transistor Q ₁ , Q ₂ -- Contact CK ₁ -- Rectifier REC ₁ -- Office line connection terminal L ₂ .

Therefore, the transfer side telephone TEL ₁ and the transferred side telephone TEL ₃ are connected to the central office line, and communication to the effect of transfer can be performed using the central office power supply.

When the transfer telephone TEL ₁ lowers the handset, even if it raises the handset again, the office line is pulled into the telephone TEL ₃ and the inter-office line voltage drops significantly.
The Zener diode ZD ₁ of the additional device ADP ₁ cannot be operated, and the telephone TEL ₃ remains confidential.

(C) Next, we will explain the case where the person performing the transfer operation and the person receiving the transfer are the same person, and the person continues to talk to the other party using a telephone other than the one on which the handset is raised. Since the operation is the same up to the state (a) mentioned above, we will start from there.

After the transfer operation using the additional device ADP ₁ on the transfer side, when the handset of telephone TEL ₁ is lowered, transistors Q ₁ and Q ₂ of the privacy circuit and transistor Q ₃ of the deprivation circuit become non-conductive, and the telephone TEL ₁ is transferred from the central office line loop. is disconnected, and the station line is held only in the following holding loop.

Office line connection terminal L ₁ --- (Additional device ADP ₁ ) ---
Rectifier REC ₁ --- Hold music sending circuit MOH --- Resistor R ₁₄ --- Thyristor SCR --- Resistor R ₁₈ --- Rectifier REC ₁ --- Office line connection terminal L ₂ .

Next, when the person who performed the transfer operation moves and raises the handset of the transferred telephone TEL ₃ , the hold loop of the additional device ADP ₁ is released as described in (b) above, and the office line is placed in the following loop. Connected only to the forwarding phone TEL ₃ .

Office line connection terminal L ₁ --- (Additional device ADP ₃ ) ---
Rectifier REC ₁ -- Telephone TEL ₃ -- Transistor Q ₁ , Q ₂ -- Contact CK ₁ -- Rectifier REC ₁ -- Office line connection terminal L ₂ .

Therefore, it is possible for one person to change telephones and continue talking without having to perform any troublesome operations. In addition, after performing the transfer operation, put down the handset,
Even if you forget, the central line voltage will drop due to shearing when a subscriber is locked out on the exchange side, so you should use a capacitor.
_C3 is discharged and the thyristor SCR becomes non-conducting.
Therefore, the hold is automatically released.

In the embodiment, if only the telephone TEL ₁ has the function of transferring, the hold circuit is an additional device.
It only needs to be provided for ADP ₁ .

In the embodiment, the telephone set and the additional device are described separately, but there is no particular need to separate them, and the additional device may be incorporated into the telephone set.

Although a circuit diagram of a parent-child telephone device is shown in the embodiment, the present invention is not limited to this circuit diagram.

Next, if you connect only one telephone with the additional device of the present invention to the central office line, it will be equipped with a hold function, so if you operate the hold switch mid-way through the conversation, even if you have a meeting with someone nearby, you will not be able to communicate via the central office line. This eliminates the need for the other party to hear the hold music, and if a hold music sending circuit is also provided, the hold music can be sent out.

Further, a parent-child telephone device can be constructed simply by connecting the required number of telephones of the present invention in parallel to a pair of office lines.

(Effects) As explained above, the parent-child telephone device of the present invention uses the local power source for all confidential conversations, hold calls, and transfers, so there is no need for a commercial power source or a dedicated power source such as a dry battery. Since the deconfidential signal is sent as DC information, no transformer is required. Furthermore, since the hold and hold release are controlled by semiconductor switching elements and capacitors, a compact parent-child telephone device can be constructed.

Also, since the CPU etc. are not used for hold control, no current is required from the exchange side when the central office line is released.

Further, according to the present invention, the transfer can be performed even if the person making the transfer and the person receiving the transfer are the same person.

In addition, to release a user from hold, it is sufficient to simply lift the handset of one of the telephones.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an example of the present invention, and FIG. 2 is a parent-child telephone device that is an example of the present invention. REC, REC ₁ , REC ₂ ... Rectifier configuring the diode bridge, S... Secret circuit, Q ₁ , Q ₂ ...
...Transistor that constitutes the secret circuit, ZD ₁ ...Zener diode, SR...Secret release circuit, Q ₃ ...
...transistor, CK ₁ , CK ₂ ... call switch contact, C ₁ , C ₂ ... capacitor, HL ... hold circuit, CNT ... control section, SD ... sounder, MOH
... Hold music sending circuit, SW ... semiconductor switching element, SCR ... thyristor, C ₃ ... capacitor, Q ₅ , Q ₆ , Q ₇ ... transistor, LED ... transfer indicator.

Claims (1)

[Claims] 1. In a parent-child telephone device consisting of a plurality of telephones connected in parallel to one telephone line, each telephone is connected by two talking lines, one calling line, and one control line, and each A rectifier is provided in the telephone to rectify the voltage appearing on the telephone line and apply it to the telephone line, and between these telephone lines there is a semiconductor switching element having a self-holding function, and the telephone line is held by conduction between the semiconductor switching element. a capacitor charged by conduction of the switching element, a contact of a call switch for hold transfer, a transfer call signal generation circuit, a voltage discrimination type secret call circuit, and a secret call circuit of the secret call circuit. by connecting a circuit for canceling the call and a hold display circuit, and operating the call switch provided on a telephone connected to a telephone line, triggering the semiconductor switching element having the self-holding function to make it conductive; A holding loop is formed in the DC closing circuit to put the telephone line on hold, and at the same time, a holding display circuit provided in another telephone is connected between the telephone lines via the DC closing circuit and the control line. When activated, it displays that the line is on hold, and while the call switch is operating, the transfer call signal generation circuit of another telephone is connected between the telephone lines via the DC connection circuit and the call line. When the other telephone picks up the handset, the circuit for canceling the secret is connected between the telephone lines and activated. When the confidentiality is released and the voltage across the telephone line drops due to the connection of the transferred telephone to the telephone line, the semiconductor switching element having the self-holding function is self-holding due to the discharge of the charged capacitor. A parent-child telephone device characterized in that it is configured such that the hold state of a telephone line is released when the telephone line is released from a hold state.