JPS61201542A - Holding automatic release device in master and slave telephone set - Google Patents

Abstract

PURPOSE:To release the holding only with the operation of lift of a handset by inserting a semiconductor switching element having the self-hold function in series with a parallel circuit comprising a resistor and a capacitor and using a voltage drop between trunk lines caused by the lift of handset of a telephone set connected in parallel to discharge a charge of the capacitor. CONSTITUTION:When a voltage by holding is fed to a gate of a thyristor SCR, the thyristor SCR is conductive and a capacitor C is charged by a voltage between trunk lines. Further, the trunk line is closed by a holding resistor R1. In releasing the holding, when a handset of any telephone set is lifted, the voltage between trunk line connecting terminals L1 and L2 is dropped and the capacitor C starts discharging to the resistor R1. Then the voltage fed to an anode of the SCR is lowered, the current flowing to the SCR is decreased to a current below the holding current or lost, the SCR is nonconductive and the holding state is released.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to connecting a plurality of telephones or telephones with additional equipment in parallel to a telephone line (hereinafter referred to as central office line) from a central office exchange to a terminal telephone of a subscriber's telephone. The present invention relates to an automatic hold release device provided in a parent-child telephone device, etc.

(Prior art) In conventional parent-child telephone devices, the holding operation and release were performed mechanically, or even if they were electronic, they used the power supply provided within the device rather than the central 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 the call from hold by simply lifting the handset on the telephone itself, it was not possible to release the call from hold by simply lifting the handset on a telephone other than the one that placed the call 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 in order to view materials, etc., he/she may raise the handset and receiver of the telephone installed on the -floor. I went straight to the second floor and picked up the handset of the transferred phone, returned to the - floor and lowered the handset of the transferred phone.
I had to go upstairs again and resume the call to 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.

The object of the present invention is to solve the above-mentioned drawbacks, and to provide a parent-child telephone that uses a small semiconductor switching element and a capacitor to release the hold by simply lifting the handset of the transmitting or transferred telephone. An object of the present invention is to provide an automatic hold release device for a device.

(Means for solving the problem) In a parent-child telephone device configured by connecting a plurality of telephones in parallel to a central office line, a resistor is connected between the central office lines in at least one telephone or a device added to the telephone. A parallel circuit consisting of a capacitor and a capacitor is inserted, and a semiconductor switching element having a self-holding function is inserted in series with this parallel circuit. When holding the local line, the semiconductor switching element with the self-holding function is triggered to conduct, and a holding loop is formed with the parallel circuit of the resistor and capacitor for the local line, and at the same time, the capacitor is connected to the local line. Charge by voltage. The electric charge in the capacitor is discharged by the voltage drop between the office lines due to the handset of the telephone set itself or those connected in parallel being raised.

This discharge releases the self-holding of the semiconductor switching element having the self-holding function, and the holding loop for holding is released.

(Function) To transfer, all you have to do is press the call switch on the telephone that connects the central office line, and you can leave the handset of the transferring telephone up or down. . No special operation is required on the transferred side telephone to receive the transfer, and it is possible to talk to the transferred side telephone and the peripheral side simply by lifting the handset. In addition, even if the handset is put down after being put on hold and then forgotten, the hold is canceled due to a drop in the office line threshold voltage caused by the shunting at the time of subscriber lockout in the exchange, and the telephone automatically returns to its original state.

(Implementation Nl) FIG. 1 shows an automatic hold release device which is an embodiment of the present invention. SCR is a cyrisk as an example of a semiconductor switching element with a self-holding function, C is a capacitor,
R8 is a resistor that holds the central line.

Next, this operation will be explained.

When a voltage due to a hold operation is applied to the gate of the thyristor SCR, the thyristor SCR becomes conductive, and the capacitor C is charged at the station line threshold voltage. Also, the station line has a holding resistance R
It is closed by 1.

As a result, capacitor C starts discharging into resistor R1. As a result, the voltage applied to the anode of the thyristor SCR is reduced, and the current in the thyristor SCR becomes less than or equal to the holding current, or disappears, and the thyristor SCR becomes non-conductive. As a result, the pending state is released.

(Embodiment 2) FIG. 2 is a system diagram configuring the automatic hold cancellation device as an actual circuit to form a parent-child telephone device.

REC and REC2 are rectifiers, SCR is a thyristor that is an example of a semiconductor switching element with a self-holding function, C is a capacitor, R, R, are resistors, SD is a sounder that sounds when a transfer call occurs, and LED is a Transfer indicator lights up at 9 during transfer call, CK + CK 2 position,
is a telephone. ADPI, ADPI, ADP3 are telephone +, position 2. This is an additional device connected to each of the three locations, and the contents are the same for each.

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

Next, the operation will be explained.

Operation of making a call to a central office line When the handset is raised to make a call to a central office line, a hook switch contact (not shown) is activated and the following route is closed.

Office line connection terminal - rectifier REC, - secret line S - call switch contact CKI - rectifier REC, - telephone set telephone - office line connection terminal L2゜ The above loop conducts the secret line S, and the telephone set +
The central office line communication circuit is closed and the central office line is captured.

In this state, another telephone, for example T E L z, attempts to acquire the central line by raising the handset and activating the hook switch contact. However, the station line connection terminal at this time.

Circuit S is not conductive. Therefore, everything except telephone equipment is disconnected from central office lines.

Incoming call operation When a bell signal arrives from the exchange side when a call arrives on the central office line, the telephone equipment +, 2, etc. The office line connection terminal L1- is connected to the
Rectifier REC, - Confidential circuit S - Calling switch contact CK,
- Rectifier REC, - Telephone equipment (equipment 2.) A bell signal is applied through the route of the single-station line connection terminal L2, and each telephone displays an audible display of incoming calls on the central office line. When the handset is raised, the confidential circuit S of the telephone whose handset is raised becomes conductive, as in the case of making a call to the central office line described above, but the confidential circuit S of the telephone whose handset is not raised becomes non-conductive. is pulled into a telephone with the handset raised, and only this telephone can answer incoming central office calls.

Transfer operation Next, as an example, from telephone installation + during a call on a central office line, telephone installation,
The operation when transferring to 1 will be explained.

In this case, when the call switch provided on the additional device ADPI is operated, the call switch contact CK is activated.

and CK2 are driven to a state opposite to that shown in FIG. 2, and thyristor SCR is activated and becomes conductive through the following route.

Office line connection terminal L1-rectifier REC, -secret circuit S-contact CK, -gate of thyristor SCR-rectifier REC! −
By activation of the office line connection terminal L2° thyristor SCH, the office line is held in the following loop.

Office line connection terminal L1 - Rectifier REC2 - Resistor R8 - Thyristor 5CR - Rectifier RE Cz - Office line connection terminal L2゜Also, due to conduction of thyristor SCR, capacitor C when on hold
is charged via the following route.

Office line connection terminal Ll - Rectifier RE C2 - Capacitor C -
Thyristor 5CR - Rectifier RECZ - Office line connection terminal L2
゜Additional device AD is activated by operation of call switch contact CK2.
Sounder SD of P, sounds, and other additional equipment A
D P z, A D P 3 sounder is calling line L3
to notify that a call for transfer has occurred by ringing through the .

Next, the call switch CK (not shown) of the additional device ADP is returned. However, since the Cyrisk SCR has a self-holding function, it continues to conduct and maintains the station line hold state. Here, the transfer indicator LED of the additional device ADP lights up, and the transfer indicators LED of the other additional devices also light up via the control line L4.

Further, the privacy circuit S is rendered inactive (non-conducting) by the privacy canceling circuit SR.

(b) When the handset of the telephone station 3 is raised in response to a transfer call, the deprivation circuit SR of the additional device ADP3
is connected to the additional device ADP via the control line L4.

The confidential communication circuit S is brought into operation (conducting state) under the control of the circuit. Therefore, the central office line is connected to the telephone T E by the following loop.
Since it is also connected to the Lx loop, the voltage between the station line terminals decreases.

Office line connection terminal - (additional device ADP)) - rectifier RE
CI - Secret communication circuit S - Contact CK, - Current restrictor REC, - Telephone T E L 3 - Office line connection terminal L2 Capacitor C with additional value fiADP+ that performed the transfer operation due to this voltage drop
discharges into the resistor R, so the anode potential of the thyristor SCR drops rapidly and becomes reverse biased, causing the thyristor S
CR becomes non-conductive.

When the thyristor SCR becomes non-conductive, it turns off the transfer indicator LED and controls the privacy release circuit SR to operate the privacy circuit S. Additional device ADP on this transfer side.

Due to the operation (continuity) of the confidential communication circuit S, the transfer side's telephone is disconnected,
is connected to the central office line again through the following loop.

Office line connection terminal L+- (additional device ADP+") - Rectifier REC, - Secret communication circuit S - Contact CK l - Rectifier REC,
- Telephone equipment - The telephone station and telephone station 3 are connected to the central office line through the central office line connection terminal L2, and a notification of transfer is made from the telephone TEL+ to the telephone station.

Once the transmitter's handset is lowered, the secret circuit S becomes non-conductive, and even if the handset is raised again, the voltage between the central office line connection terminals has dropped significantly due to the telephone being put down, so the secret circuit S is disconnected. However, if the phone is disconnected and the phone is turned off, the conversation remains confidential.

(c) Next, we will explain the case where the person making the transfer and the person receiving the transfer are the same person. The operation to perform the transfer was explained in (a) above, so the subsequent explanation will be given below.

After the transfer operation at the transfer side's telephone equipment, when the handset is lowered, the central office line is held only in the holding loop shown below.

Office line connection terminal - Rectifier W RE CI - Resistor R1 - Cyrisk 5CR - Rectifier REC, -, - Office line connection terminal L
2゜Next, the person who made the transfer moves to the transferred phone.

When the handset is raised, the holding loop of the telephone is disconnected as described in (b) above, and the central office line is connected only to the telephone device 3 on the transferred side in the following loop.

Office line connection terminal L+ (additional device ADP3) - Rectifier REC, - Secret communication circuit S - Contact CK, - Rectifier RE
C. - Telephone equipment, - Office line connection terminal L2°, so that - it is possible to change telephones and continue talking without the need for a person to perform troublesome operations. Note that even if you put down the handset after performing a transfer operation and forget about it, the station line voltage will drop temporarily due to the disconnection at the time of subscriber lockout on the exchange side, causing the capacitor to discharge and causing the thyristor SCR to become non-conducting. Become. Therefore, the hold is automatically released.

In addition, if the handset of either transferred telephone equipment 2y or 3 cannot be raised after being put on hold, by turning off the hook switch of the transferred telephone equipment I momentarily, the hold will be canceled and the telephone equipment will be connected to the central office line. It turns out.

In the second embodiment, if only the telephone station I is provided with the function of transferring, the automatic hold release device may be provided only in the additional device ADPI.

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

Although the second embodiment shows a system diagram of a parent-child telephone device, the present invention is not limited to this system diagram.

Example 3゜ FIG. 8 shows another embodiment of the automatic hold release device.

Ql is a transistor that operates (conducts) during suspension, R8゜R
4*R5tR6 is a resistor.

Since the parent-child telephone device is the same as that in the second embodiment, only the hold release device will be described below.

When the thyristor SCR is triggered by the hold operation, the thyristor SCR conducts through the route of the station line connection terminal L+ - resistor R3 - thyristor 5CR - resistor R4 - station line connection terminal L2, and holds the station line, and the capacitor C connects the station line. Connection terminal L+
- Capacitor C - Thyristor 5CR = Resistor R, - Charged through the route of the office line connection terminal L2. Thyristor S
Due to the conduction of CR, a base current flows through the transistor Ql, and the transistor Ql enters the operating state.

Next, when the handset of either telephone is raised, the voltage drop across the office line causes capacitor C to begin discharging into resistor R3. This discharge lowers the anode voltage of the thyristor SCH and renders the thyristor SCR non-conductive, but the gate of the thyristor SCR becomes connected to only the resistor R2 because the resistor R4 is short-circuited due to the operation of the transistor Q1. Therefore, the resistance between the gate and the cathode of the thyristor decreases, and the thyristor SCR easily becomes non-conductive corresponding to this decrease. When the thyristor SCR becomes non-conductive, the hold of the central office line is released.

(Effects) As explained above, the present invention creates a compact automatic hold release device using a semiconductor switching element and a capacitor having a self-holding function, and configures a parent-child telephone device to communicate with a person who transfers information. The recipient may be the same person. In addition, to release the hold, it is sufficient to simply lift the handset, and there is no need to put the exchange on invalid hold.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an automatic hold release device that is an embodiment of the present invention, FIG. 2 is a system diagram of a parent-child telephone device, and FIG. 3 is a circuit diagram of an automatic hold release device that is another embodiment of the present invention. . S CR-m-thyristor, C---capacitor, R
1s R8--1 resistor, CKI, CK2--1 call switch contact, RECl
, RFe5-- rectifier, Ql-- one transistor 5D-- sounder, LK
D--Transfer indicator, TKL1* position 2. TKL3--One telephone, ADPl, A
DP2, ADP8--an additional device, S--a privacy circuit SR-m--a de-privacy circuit.

Claims (2)

[Claims] (1) In a parent-child telephone device configured by connecting multiple telephones in parallel to a telephone line, a parallel circuit of a resistor and a capacitor is connected in series between the telephone lines in at least one telephone or a device attached to the telephone. A semiconductor switching element having a self-holding function is inserted into the telephone line, and when the telephone line is put on hold, the semiconductor switching element having the self-holding function is triggered to conduct, and the resistor and capacitor are connected to the telephone line. A holding loop is formed by a parallel circuit, and at the same time the capacitor is charged by the voltage of the telephone line, and the voltage between the telephone lines at the time of holding is memorized, and when the own telephone or another telephone connected in parallel answers the telephone line again. As the electric charge in the capacitor is discharged due to the resulting voltage drop, a reverse voltage is applied between the anode and cathode of the semiconductor switching element having a self-holding function, and the self-holding state is released, and the telephone line is automatically released from the hold state. An automatic hold release device for a parent-child telephone device. (2) Inserting a transistor that operates by detecting the current flowing through the semiconductor switching element having a self-holding function according to claim 1, and by making the transistor conductive,
Automatic release of hold in the parent-child telephone device according to claim 1, characterized in that the resistance between the gate and cathode of the semiconductor switching element having a self-holding function is reduced to reduce the release current of the semiconductor switching element. Device.