JPH0249072B2 - DENWAGATATANMATSUSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a telephone type terminal device that performs data communication with a host computer.

(b) Conventional technology In recent years, telephone-type terminal devices have begun to be widely adopted in credit card verification and banking operations. Application of
An overview of various telephone terminal devices is disclosed.

In such devices, it is necessary to prevent data communication due to unauthorized use by third parties as much as possible, but in conventional devices, the dial circuit is always in an operable state.
No measures were taken to prevent unauthorized use.

(c) Problems to be solved by the invention As a method to prevent unauthorized use by a third party, a state holding circuit such as a flip-flop or latching relay circuit is set in response to a predetermined key operation on the keyboard. It is conceivable to provide a dial limiting circuit that stops the dial function of the dial circuit depending on the state of the state holding circuit.

However, if the state holding circuit is implemented using a circuit configuration such as a flip-flop that operates on the power supply voltage from a commercial power supply, the flip-flop will be reset once the power is turned off, so if the power is then turned on again, the dial will be reset. The circuit returns to an operational state and data communication becomes possible.

Furthermore, when using a latching relay circuit, the set state is normally maintained regardless of whether the power is turned on or off, but when the power is turned off, the state may be reversed and reset due to vibration, etc. However, there was still the problem that data communication became possible when the power was turned on again.

(d) Means for Solving Problems The present invention provides a non-volatile memory that stores as information the setting status of a state holding circuit by operating a predetermined key on a keyboard, and a non-volatile memory that stores, as information, the setting status of a state holding circuit by operating a predetermined key on a keyboard. and means for correcting the state of the state holding circuit.

(e) Effect In the present invention, when a predetermined key operation is performed on the keyboard, the state holding circuit is set and information indicating the set state is stored in the nonvolatile memory. Even if the state holding circuit is reset for some reason after the power is turned off or shut off, if the power is turned on again, the state holding circuit will be reset according to the information in the nonvolatile memory.

(f) Embodiment FIG. 1 is a block diagram showing the overall configuration of a telephone terminal device according to the present invention, in which 1 is a diode bridge circuit connected to a telephone line 2, and 3 is a piezoelectric circuit for receiving a call signal. A ringer detection circuit drives the buzzer 4; 5 is a switch inserted into the telephone line 6; 7 is a communication circuit connected to the telephone line 6; 8 and 9 are a transmitter and receiver; 10 is a dial pulse switch 11 that turns on and off. a pulse dialer that controls and sends out dial pulses corresponding to a telephone number; 12 corresponds to a telephone number;
A tone dialer 13 that sends out a DTMF (dual tone multi-frequency) signal is connected to the telephone line 6, and the output voltage is set to the power supply voltage V _DS
This is a regulator circuit that supplies the dialers 10 and 12 and the telephone communication circuit 7 as a main terminal.

Further, 14 is a keyboard equipped with a plurality of operation keys such as function keys, character keys, number keys, etc.;
5 is a CPU that constitutes a control circuit together with I/O interfaces 16 and 17, 18 is a display device, and 19 is a RAM 20 for storing communication data sent and received with the host computer.
A memory consisting of an EPROM 21 that stores various programs such as an initialization program when the power is turned on, and an E ² PROM 22 that serves as a non-bright generation memory that stores data that you do not want to erase even when the power is turned off, such as a telephone number. 23 is a modem that converts communication data and telephone signals; 24 is a pulse dialer 10 and a tone dialer 12 according to the output signal of the I/O interface 16;
dial-limited circuit that controls the dial function of 2
5 inputs the commercial power supply voltage via the power plug 26, and applies the power supply voltage to each part of the CPU 15, I/O interfaces 16 and 17, memory system 19, etc.
This is a power supply circuit that supplies V _DD , and the dial limited circuit 24 receives the power supply voltage from the regulator circuit 13.
V _DS is also supplied.

By the way, as the pulse dialer 10 and the tone dialer 12, for example, the dialer ICMK50992 and MK5089 manufactured by Mostek may be used, and these ICs have terminals for controlling the dial function on pin 17 and pin 2, respectively. Ori,
When the input signal to the 17th pin is at the "H" level or in the open state, and when the input signal to the 2nd pin is at the "L" level, the dialing function of each dialer is stopped.

FIG. 2 is a circuit diagram showing a specific configuration of the dial limited circuit 24, in which the collector is connected to the 2nd pin of the tone dialer 12, the emitter is grounded, and the base is connected to the power supply voltage through resistors 25 and 26.
Switching transistor 27 connected to V _DS
and a switching transistor 30 whose collector is connected to pin 17 of the pulse dialer 10, whose emitter is grounded via a switch 28, and whose collector is connected to the power supply potential _VDS via resistors 29 and 26; A switching transistor 31 whose collector is connected to the base of 30 and whose emitter is grounded, and resistors 25 and 2
The output is connected to the connection point P of 9, and the selection switch 32 selects between a pulse dialer and a tone dialer, and a signal from the I/O interface 16.
A latching relay circuit 33 is provided which is set and reset by CN1 and CN2, and the C terminal of the contact 34 of the latching relay circuit 33 is connected to the power supply potential V _DS via a resistor 35, The M terminals of diodes 36 and 37
are connected to the bases of switching transistors 27 and 31, respectively.

Furthermore, the E ² PROM 22 shown in FIG.
3 is configured to store a limited dial flag FG indicating whether it is set to set or reset when a predetermined key is operated, and the flag FG is set to "1" when set, and
"0" is written during reset.

Next, the operation of this embodiment will be explained.

Normally, the latching relay circuit 33 is in a reset state, the contact 34 is coupled to the B side, and the power supply voltage V _DS is not supplied to the terminal M. At this time, the limited dial flag FG is set to "0". In this state, when the selection switch 32 is set to the DTMF side as shown in the figure, the connection point P between the resistors 25 and 29 is grounded, so the switching transistors 27 and 30 are turned off, and both dialers 12,
Input signal of pin 2 and pin 17 of 10 and
Both OHTs are in an open state. Therefore, the tone dialer 12 becomes operational, and the pulse dialer 10 becomes inactive, stopping the dialing function.

If the selection switch 32 is set to the DP side, the connection point P
Since the power supply voltage V _DS is supplied to through the resistor, the switching transistors 27 and 30 are both turned on, and the input signal and OHT become "L". Therefore, in this case, the tone dialer 12 becomes inactive and the pulse dialer 10 becomes operable.

Thus, when the latching relay circuit 33 is in the reset state, one of the dialers is selected according to the selection switch 32.

However, when a predetermined key operation is performed on the keyboard 14,
For example, if you specify limited dial mode by operating keys ENTER → A3 → □1, CPU1
5 responds to this key operation, sets the output signal CN1 of the I/O interface 16 to "H", and at the same time sets the dial limit flag of the E ² PROM 22.
Set FG to "1". When the signal CN1 becomes "H", the switching transistor 38 is turned on, current flows through the setting coil 39, the latching relay circuit 33 is set, and the contact 34 is coupled to the M side. Therefore, the power supply voltage V _DS is
via switching transistors 27 and 3
1, these transistors are turned on, and switching transistor 30 is turned off. Therefore, the input signal becomes "L", the input signal OHT becomes open, and both dialers 10 and 12 become inactive, and the dialing function is stopped.

Once the latching relay circuit 33 is set, it maintains the set state even if the power supply voltage V _DD from the power supply circuit 25 is cut off, so that the power supply voltage V _DD remains unchanged.
If a specific dialing mode is set while the power supply is being supplied, the dialing functions of the dialers 10 and 12 will remain stopped even if the power plug 26 is pulled out, and data communication and voice calls will be impossible.

Now, suppose that in the limited dial mode, after the power plug 26 is unplugged, the latching relay circuit 33 is reversed and reset due to vibration or other causes. In this state, one of the dialers selected by the selection switch 32 becomes operational and voice communication is possible. However, since the power supply voltage _VDD is not supplied to the CPU 15, I/O interfaces 16 and 17, etc., data communication cannot be performed.

Then, turn the power back on. When the power is turned on again, the initial program stored in the EPROM 21 is activated and the process shown in the flowchart of FIG. 3 starts. That is, the contents of the limited dial flag FG of the E ² PROM 22 are read and it is determined whether the contents are "0". And if it is "0"
CN2 is set to "H", and if it is "1", CN1 is set to "H". In this case, since the flag FG is "1", CN1 is set to "H", and the latching relay circuit 33 is reset accordingly. Therefore, even if the power is turned on again, the limited dial mode is set again, the dial function is stopped, and data communication is no longer possible.

Of course, if the latching relay circuit 33 is set due to vibration or the like without a predetermined key operation being performed, the latching relay circuit 33 will be reset by turning the power back on.

To cancel this limited dial mode, press the specified key, for example, ENTER → A3 → □0.
, the CPU 15 responds to this key operation and sets the signal CN2 to the "H" level, so the switching transistor 40 turns on, current flows through the reset coil 41, and the latching relay circuit 3
3 is in the reset state, and the contact 34 is connected to the B side. Therefore, one dialer selected by the selection switch 32 returns to the operable state.
Then, by this key operation, the limited dial flag is set.
FG is rewritten from "1" to "0".

(G) Effects of the Invention According to the present invention, it is possible to reliably prevent unauthorized data communication by a third party, and to realize a telephone terminal device that is extremely reliable in terms of security.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, FIG. 2 is a detailed circuit diagram of the main part of this embodiment, and FIG. 3 is a flowchart showing the processing contents of this embodiment. Explanation of main drawing numbers, 2...Telephone line, 10...Pulse dialer, 12...Tone dialer, 1
4...keyboard, 15...CPU, 24...dial limited circuit, 25...power supply circuit, 33...latching relay circuit.

Claims (1)

[Claims] 1. A keyboard with multiple operation keys, a dialing circuit that sends dialing signals to the telephone line,
A dial limiting circuit comprising a state holding circuit that is set or reset in response to a predetermined key operation on the keyboard, and circuit means for stopping the dialing function of the dial circuit according to the state of the state holding circuit. In the telephone type terminal device, a non-volatile memory stores the setting status of the state holding circuit by the predetermined key operation as information, and a state of the state holding circuit is stored according to the information in the non-volatile memory when the power is turned on again. 1. A telephone-type terminal device, characterized in that it is provided with means for correcting.