JPS61283264A - Memory dial telephone set - Google Patents

Abstract

PURPOSE:To prevent a storage content such as abbreviation dial from being lost because of non-feeding state of a dial memory when the memory is disconnected from a telephone line while being off-hook by switching power depending on the output of a current supply circuit in place of the state of a hook switch. CONSTITUTION:When off-hook takes place, a hook switch HS is closed and a DC voltage decide by the DC resistance of a talking circuit 4 is produced at a point P. Since the DC voltage of the talking circuit 4 is 3.0V or, above with respect to the DC bias point of a transmission amplifier, a voltage applied to the cathode of a diode D4 is not lower than 2.3V in the worst feeding condition even when the emitter-collector voltage drop of a transistor Q3 and the voltage drop of a diode D1 are subtracted. Since the voltage is higher, off course, then the worst voltage in the voltage state connected to a general subscriber line, the diode D4 as a discharge is turned off, the discharge circuit of a battery BT is interrupted and no power of the battery BT is consumed during this time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a nine-memory dial telephone equipped with a dial memory, such as for storing speed dials.

[Conventional technology]

Conventionally, in this type of dial memory, when a predetermined power supply current is supplied from the loop current through the current supply circuit when off-hook, and is backed up by a battery when on-hook, the power supply switching method is to use two interlocking hooks. Some of this was due to the cooperation of switch contacts. In other words, when off-hook, the first
A loop is formed by the hook switch to supply current to the dial memory, and a second hook switch cuts off the battery discharge circuit, while on the other hand, when on-hook, the first hook switch cuts off the supply of loop current. Together with the second hook switch, a battery discharge circuit is formed.

[Problem that the invention seeks to solve]

However, when a memory dial telephone equipped with such a dial memory is used as a main telephone for a fax machine, and the line is switched to the fax side to perform off-hook communication, or when a switchable parent-child telephone is used. If you forget to turn the phone on-hook after switching to the other phone, or if you use it as a plug-in phone and unplug it while it is off-hook, the power supply must be switched correctly in synchronization with the closed state of the DC loop. There is a problem in that, if the dial number is not working properly, both power supplies are cut off and the dial number stored in the dial memory is lost.

[Means for solving problems]

In order to solve these problems, the present invention provides loop 1! when on-hook. A series circuit consisting of a rechargeable battery and a discharge switch diode is connected in parallel to the output terminal of a current supply circuit that extracts and supplies a predetermined current from the current. A Zener diode having a voltage is connected thereto, and the circuit is further provided with a circuit that uses the battery as a power source and sends out a seven-switch signal to the dial memory depending on the presence or absence of an output from the current supply circuit.

[Effect]

Depending on the state of the hook switch, the power source is switched depending on the output of the current supply circuit.

〔Example〕

The figure is a circuit diagram showing one embodiment of the present invention. In the figure, numeral 1 represents a dial pulse generating circuit made of an integrated circuit (IC). 2 is a diode bridge which connects line terminals L1.
The polarity of the loop xi supplied to L2 is kept constant and output. The loop current charges the capacitor C1t through the diode D1, and its terminal voltage is supplied to the dial pulse generation circuit 1 as the power supply voltage vDD. ZDl is a Zener diode for stabilizing the voltage. On the other hand, BT is a lithium battery that backs up the dial pulse generation circuit 1 during off-hook when no loop current is supplied.

When a key on the keyboard 3 is pressed, the dial pulse generation circuit 1 outputs a dial pulse corresponding to the input to a terminal D.
It is equipped with a dial memory and has a well-known speed dial function that sends out a dial pulse corresponding to a pre-stored dial number in response to a predetermined key operation, such as a predetermined function key. Desired dialing can be performed manually using the approximately two-digit number keys that follow.

Ql is a transistor serving as a dial contact, and is repeatedly turned on and off by the dial pulse sent from the dial pulse generating circuit 1, thereby interrupting the DC loop and sending the dial pulse to the exchange. In addition, 'Telephone circuit 4
a transistor Q2 connected in series to the dial pulse generating circuit 1, and a transistor Q3ta connected in series to the dial pulse generating circuit 1;
, is turned off during dial transmission by the output from the terminal DS of the dial pulse generation circuit 1, and maintains a high break impedance during that time. D2~D4 are diodes %R1~
R6 is a resistance element.

Here, in the on-hook state, the DC loop is cut off by the 7-way switch H8, and the point P becomes in a no-voltage state. Therefore, transistor Q4 remains off. Therefore, an "H" level potential of about 2.3 V is supplied from the battery BT to the terminal H8 of the dial pulse generating circuit 1 via the diode D4 and the resistive element R5. As a result, the dial pulse generating circuit 1 is placed in a standby state, and the built-in dial memory is backed up by this battery BT. At this time, the only current that flows is the standby current, and the power consumption of the battery BT is small.

On the other hand, when the off-hook state occurs, the hook switch H8 is closed and a DC voltage determined by the DC resistance of the communication circuit 4 is generated at point P. Calling side lol! Since the DC voltage of No. 4 is 3.0 V or higher due to the relationship with the DC bias point of the transmitting amplifier, even if the voltage drop between the emitter and collector of transistor Q3 and the voltage drop of diode D1 are subtracted, the voltage drop across diode D
The voltage applied to cand No. 4 will not drop to 2 or 3 V even under the worst power supply conditions. In a normal state connected to a general connection, the worst value is of course higher than this, so the diode D4 as a discharge switch is turned off (in order to guarantee this relationship, the Zener diode zD1 is
The Zener voltage of the battery is set to a value greater than the voltage of the battery BT). As a result, the discharge circuit of Shibatsute')-BT is cut off, and there is no power consumption of battery BT during this time. On the other hand, if the DC loop is cut off by an external switching device, hook switch H8 is closed. Even if the transistor Q4 is
is off, a hook switch signal of "H" level is sent to the terminal H8 of the dial pulse generating circuit 1 in the same manner as described above. As a result, the dial pulse generating circuit 1 is placed in standby mode, and the built-in dial memory is powered up by the battery BT.

〔Effect of the invention〕

As explained above, according to the present invention, a backup diode in which a discharge switch diode is connected in series to the output terminal of a current supply circuit that extracts a predetermined current from a loop current, and a Zener with a voltage higher than the battery voltage. By connecting zener diodes with voltage in parallel, power is secured for on-hook and off-hook, and a hook switch signal sending circuit is provided that uses the battery as a power source. Since the hook switch signal is sent to the memory, switching between the two chamber sources is done by monitoring the output of the current supply circuit itself. It is possible to prevent the dial memory from being in a powerless state and losing stored contents such as speed dials.

[Brief explanation of drawings]

The figure is a circuit diagram showing one embodiment of the present invention. 1...-Dial pulse generation circuit with built-in dial memory, 2@...Current supply circuit t-Constituting diode/ridge, BT--Backup battery, D4
-...Discharge switch diode, Ll, L2...
... Line terminal, R5 ... Resistance element that constitutes the hook switch signal sending circuit, Q4 ... Same transistor,
zDl・φ・・Zener diode.

Claims (1)

[Claims] Connected to the output end of the current supply circuit in a memory dial telephone equipped with a dial memory that is supplied with power current by a current supply circuit that extracts a predetermined current from a loop current when off-hook and backed up by a battery when on-hook. a series circuit of the battery and a diode for a discharge switch; a Zener diode having a Zener voltage higher than the voltage of the battery connected in parallel to the series circuit; and a current supply circuit using the battery as a power source. A hook switch signal sending circuit is provided for sending a hook switch signal to the dial memory depending on the presence or absence of an output, and the power supply to the dial memory is switched by monitoring the output of the current supply circuit. A memory dial phone featuring: