JPH0124457B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention has a so-called redial function, obtains connection/disconnection status data of a switch based on line current, and stores dial key data in a storage unit. The present invention relates to a telephone dial circuit configured to be used for control when writing.

[Technical background of the invention]

A conventional dialing circuit having a redialing function will be described with reference to FIG.

The lines 2 are connected to a private branch exchange, and for example, one line 2 is given earth voltage and the other line 2 is given a voltage of about 10V. The current flowing from this line 2 is
It reaches the rectifier 3 via the first switch 1a and is rectified. By being rectified, approximately 10V appears on line 100A and 0V appears on line 100B.

This voltage of 10V is lowered to a predetermined voltage at point _P1 by the resistor 4a and the Zener diode 5. The charge from point _P1 reaches the capacitor 12b via the diode 6 and is stored therein. Further, a voltage is applied to the dial signal sending IC 7 via the diode 6 and the line 100B, and the IC 7
The data stored in the storage unit 11 inside the computer is designed not to be erased. The HS terminal of IC7 has
A voltage is applied through the resistor 4d, and this voltage becomes the connection/disconnection state data of the switch for the IC7. Furthermore, this resistor 4d and the collector of the transistor 8a are connected, and the transistor 8a
The emitter of is connected to line 100B,
Resistor _4b from point P1 to the base of transistor 8a,
It is configured such that current flows through the terminal 4c. Further, a capacitor 12a is connected between the connection point between the resistor 4b and the resistor 4c and the line 100B, and when the current sent through the line 2 is cut off, the capacitor 12a is connected to the transistor 8a.
A current is applied to the base of IC 7, turning on transistor 8a to control the connection/disconnection status data of the switch applied to the HS terminal of IC7.

The IC7 also has a keypad 10 which is an input section.
is connected and dial key data (referring to data corresponding to 0, 1, ..., 9, #, *) is sent from the keypad 10, the connection/disconnection status data of the switch is referred to, Storage unit 11
Dial key data is written to and read from. When it is determined that it is time to send a dial signal based on the connection/disconnection state data of the switch and the dial key data, a DP signal (pulse) is sent to the transistor 8b in accordance with the dial key data in the storage section 11, and the transistor 8b is activated. As a result of being turned on and off, the dial signal is on line 100A, 1.
Output via 00B. Also, when IC7 sets the DP signal to L level, the MUTE signal is set to H level.
This signal is output as a level signal, turns on the transistor 8c, enables the dial tone and voice to be heard from the handset of the communication circuit 9 including the hybrid circuit and the handset, and enables the transmission of an audio signal from the handset.

In a telephone with such a configuration, when making a dial call, press the necessary key on the keypad 10, and the dial will be made on the condition that the connection/disconnection state data of the hook switch is given to the HS terminal of IC7 as the connection state. The key data is taken into the IC 7 and written into the storage section 11, and at the same time, a DP signal corresponding to the dial key data is sent out. Also, when redialing is specified, the storage unit 1
The dial key data in 1 is read out and the corresponding DP signal is sent out.

By the way, as shown in Fig. 2A, the voltage applied to line 2 from the private branch exchange is
It drops from 48V to 0V and then rises to 10V.
Here, the connection/disconnection status data of the hook switch applied to the HS terminal of IC7 is L as shown in Figure 2B.
At _T1 , when the level changes to H level and then to L level, it is indicated that the signal is off-hook.
After this, in order to make a call to the central office line, dial key data corresponding to "0" is input from the keypad 10, a corresponding DP signal is sent from the IC 7, and further,
When a dial signal corresponding to "0" is sent to the private branch exchange, the private branch exchange sets the voltage of line 2 to 0V at T ₂ in order to connect the central office line and this telephone, and after about 2 seconds, returns to T. ₃ , the voltage is 10V.
Then, transistor 8a turns off at T ₂ ,
Voltage is applied from capacitor 12b through resistor 4d.
By being applied to the HS terminal of IC7, the connection/disconnection state data of the switch shown in FIG. 2B is as follows.
It becomes H level, and becomes L level at _T3 .

Therefore, even if the caller, for example, presses the "0" key to make a call to a central office line, and then presses the key "0425 831111," the IC7 will not be able to switch the switch between _T2 and _T3 . It is assumed that the key was pressed as "0425 83 1111". Therefore, the central office line transmission becomes invalid.

Therefore, the capacitance of the capacitor 12a is increased, and between T ₂ and T ₃ in FIG.
It is conceivable to keep the HS terminal of the IC 7 at the L level as shown in FIG. 2C by causing a current to flow into the base of the transistor 8a through the resistor 4c and turning on the transistor 8a.

However, if the capacitance of the capacitor 12a is increased, an on-hook occurs at T ₄ in FIG.
Shortly thereafter, off-hook at T ₅ ,
The voltage generated on lines 100A and 100B is T ₄
The voltage at the HS terminal of IC7 decreases to 0V at T5 and rises to 10V at _T5 .
Since a is on, as shown in Figure 2 C
It does not reach H level at T ₄ but becomes H level a little later at T ₄ '.

Now, if you dialed the wrong number before T ₄ ,
Also, when the caller attempts to redial or enter another dialed number, the caller on-hook at _T4 ,
Suppose you immediately take off the hook at T ₅ . Then, new dial key data is inputted to IC7 without being notified that it has been on-hook.

In general, in IC7, when an on-hook is performed, a different input is made from the data before the on-hook, so if the on-hook is not notified, the dial key data before _T4 will be input. This means that dial key data is then input. For this, for example, T ₄
Previously keyed in "0 0425 83 1111" and pressed T ₅
If the redial key is pressed in , redialing will not be performed. Also, if you enter another dial number at _T5 , "0"
0425 83 1111" is input into the storage unit 11, which may result in an unexpected dialing signal being sent, or the storage unit 11 has a capacity that stores about 20 digits of dial key data. In some cases, dial key data with a total of 20 digits or more may be entered and cannot be stored.

[Purpose of the invention]

The present invention was made in view of the above-mentioned drawbacks, and its purpose is to prevent malfunctions even if the power supplied from the line is temporarily cut off, or even if the keys are pressed immediately after being turned on. There is no dial circuit to provide.

[Summary of the invention]

Therefore, in the present invention, the rectified line current is inputted after passing through the first hook switch, and based on this current, the hook switch connection/disconnection state data is created, and when the line is disconnected, the hook switch is It has a connection/disconnection state data creation circuit including a capacitive element that stores charge for maintaining the connection/disconnection state data of the switch in a connected state, and a second switch that operates in conjunction with the first switch. The condition is detected by the disconnection state of the second hook switch, which has a path for rapidly discharging the accumulated charge of the capacitive element when the condition is detected, and converts the connection/disconnection state data of the hook switch output from the connection/disconnection state data generation circuit into the disconnection state. A switch state detecting circuit, which takes in the connection/disconnection state data of the switch, reads/writes dial key data to a built-in storage section based on this and dial key data given from the input section, and The above object has been achieved by equipping the dial circuit with a dial signal sending section that controls sending out a dial signal when predetermined conditions are met.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a circuit diagram of a circuit that is a premise of an embodiment of the present invention. In this figure, 13' is a dial circuit, and resistors 4a, 4b, 4c, 4d, Zener diode 5, diode 6, transistor 8a, and capacitors 12a, 12b constitute a connection/disconnection state data creation circuit. This connection/disconnection state data creation circuit inputs the line current rectified by the rectifier 3 after passing through the first hook switch 1a, and creates the connection/disconnection state data of the switch based on this current. 2 is off, the on/off state data of the switch is maintained in the on state (continued to be at L level) for a predetermined period of time (2 seconds in the example shown in FIG. 2). In other words, as mentioned above, by increasing the capacitance of the capacitor 12a,
The HS terminal of IC7 can be kept at L level.

Further, in this circuit, the transistor 8a
A second hook switch 1b that operates in conjunction with the first hook switch 1a is provided between the collector of the resistor 4d and the resistor 4d. The switch 1b itself constitutes a switch state detection circuit, and when the switch 1a or 1b is turned off, the switch's connection/disconnection state data output from the connection/disconnection state data creation circuit is turned off (to H level). It has the function of In other words, as shown in Figure 2A,
When the on-hook occurs at _T4 , the first and second hook switches 1a and 1b are turned off, and an H level immediately appears at the HS terminal of IC7 via the resistor 4d as shown in FIG. 2D. Furthermore,
When the switch is off-hook at _T5 , the second switch 1b is turned on and the transistor 8a is turned off.
turns on, and as a result, the HS terminal of IC7 has an L level.
A level appears. Therefore, IC7 detects that the keypad has been on-hooked once, foresees that the next keypad operation will be discontinuous with the _previous keypad operation, and, for example, when the redial key is pressed. sends out a DP signal corresponding to the dial key data in the storage unit 11, and for example, when new dial key data is input, the DP signal that was input before _T4 and stored in the storage unit 11 is transmitted. dial key data (in this example, 0 0425 83 1111)
Clear and write new dial key data.

In addition, IC7 and transistors 8b and 8 in FIG.
c constitutes a dial signal sending unit, which takes in the connection/disconnection status data of the switch, and based on this and the dial key data given from the keypad (input unit) 10, sends the dial key data to the built-in storage unit 11. It performs read/write and controls to send a dial signal when predetermined conditions are met. The function and operation of this dial signal sending section are similar to the conventional example shown in FIG.

With the dial circuit 13' configured in this way, even if the line 2 is temporarily disconnected, the connection/disconnection status data of the hook switch will not change, and even if the hook switch is disconnected for a short period of time, it can be ensured. The connection/disconnection state data of the hook switch can be set to the off state.

Next, an embodiment of the present invention will be described with reference to FIG. In FIG. 4, the switch state detection circuit includes a photocoupler 14 connected in parallel to a capacitor 12a, a power supply 16 that supplies current to the photocoupler 14 via a resistor 4e, and a second switch connected to the power supply. 1b, and inverters 15a and 15b connected to the second switch 1b and photocoupler 14. During on-hook, the second switch 1b is off, so the photocoupler 14 side of the inverter 15b goes to L level, and current flows to the photocoupler 14. As a result, the electric charge of the capacitor 12a flows out from the photocoupler 14, the transistor 8a is turned off, and the HS of IC7 is turned off.
H level appears on the terminal. This is shown in Figure 2.
Since this is considered to be an operation at _T4 , the connection/disconnection state data of the switch is disconnected, and there is no problem like in the past. When off-hook occurs, the second switch 1b is closed, the photocoupler 14 side of the inverter 15b becomes H level, and the photocoupler 14 is turned off. Therefore, as long as the first and second hook switches 1a and 1b are off-hook, the capacitor 12 remains in the predetermined time.
Due to the action of a, the transistor 8a is turned on,
At times like between T ₂ and T ₃ in Figure 2, the HS of IC7
L level appears at the terminal.

The configuration of the dial circuit 13″ other than the above description is as follows:
It is similar to FIG. Therefore, even if the line 2 is temporarily disconnected, the connection/disconnection status data of the switch will not change, and even if the switch is disconnected for a short time, the connection/disconnection of the switch will be reliably maintained.
The off-state data can be turned off.

Although this embodiment uses an IC that sends out a DP signal, the present invention can be similarly applied to an IC that sends out an MF signal.

〔Effect of the invention〕

As explained above, according to the present invention, even if power is temporarily not supplied from the line, the connection/disconnection state data of the switch continues to indicate that the switch is connected, so that the switch can be continuously operated. Since the dial key data inputted by the operator is not erroneously divided and the correct dial key data is stored in the storage section, malfunctions do not occur.

In addition, even if the switch is disconnected for a short period of time and then connected immediately, this fact is reliably reflected in the switch's connection/disconnection status data, and dial key data that the caller did not expect is stored in the memory. stored, redialing is not performed,
This eliminates malfunctions such as a storage operation being performed even if the capacity of the storage unit is exceeded. Furthermore, if the switch is used in another circuit, it can be conveniently used as a second switch.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing a conventional example, Fig. 2 is a timing chart for explaining the operation of the conventional circuit and the circuit of the present invention, and Fig. 3 is a circuit diagram of the circuit that is the premise of the embodiment of the present invention. , FIG. 4 is a circuit diagram of an embodiment of the present invention. 1a...first switch, 1b...second
2... line, 3... rectifier,
7...IC, 9...Telephone circuit, 10...Keypad, 13...Conventional dial circuit, 13''...Dial circuit of the embodiment, 14...Photocoupler,
16...Power supply.

Claims (1)

[Scope of Claims] 1. After passing through the first switch, the rectified line current is input, and based on this current, the connection/disconnection state data of the switch is created, and when the line is disconnected, a predetermined A connection/disconnection state data generation circuit including a capacitive element that stores charge for maintaining connection/disconnection state data of a time hook switch in a connected state, and a second switch that operates in conjunction with the first switch; The disconnected state of the hook switch is detected by the disconnected state of the second foot switch, and when the disconnected state is detected, the connection of the hook switch is provided with a path for rapidly discharging the accumulated charge of the capacitive element, and is output from the connected/disconnected state data generation circuit. a switch state detection circuit that turns off/disconnected state data; and a switch state detection circuit that takes in the on/off state data of the switch, and based on this and the dial key data given from the input section, sends the dial key data to a built-in storage section. read/write, and
A dial circuit including a dial signal sending unit that controls to send a dial signal when predetermined conditions are met.