WO1990003075A1 - Electronic key for a telephone - Google Patents

Abstract

An electronic key for a telephone can be adapted to all telephones with an electronic keyboard. The secret code is memorized and can be changed as often as necessary by means of the keyboard without modification to the set itself. No energy is required to store the secret code. The electronic key is independent of the mainsnetwork, which eliminates all electrical problems associated with a key connected directly to the network.

Description

 ELECTRONIC KEY FOR TELEPHONE SET.

 The present invention is characterized by an electronic key for a telephone set.

 In a telephone set, to obtain a communication, the user dials the number of his correspondent on the keyboard (Fig. 1).

 Pressing each key on the keypad (1), when dialing, translates electrically inside the station by a short circuit between the column and the line, at the intersection of which the key is pressed.

 The telephone numbering circuit (2) perceives the short circuit and translates it either by a series of pulses, in the case of a decimal station, or by a frequency signal corresponding to the key pressed, in the case of a multi-frequency station.

 The keyboard is therefore directly connected to the dialing circuit. There is then no control of information passing from the keyboard to the numbering circuit.

 The principle of integrating an electronic key into the telephone set makes it possible to control the information emanating from the keyboard towards the dialing circuit (Fig. 2).

 The electronic key (Fig. 3) object of the present invention, once integrated into the telephone set, can pass information only when it has received an appropriate code.

 The adaptation of the electronic key to telephone sets is as follows:

 When the subscriber acts by pressing a key on the keyboard, the electronic key performs one of the following operations:

 a) code test (by the microcontroller) (4),

 b) memorization of the new code (thanks to the EEPROM) (5),

 c) transmission of the number to the set (numbering circuit), which transmits, to the central office (line a / b), the signals necessary for establishing the call.

 The microcontroller tests the presence of a key pressed on the keyboard and deduces the value.

 Generally, pressing a key results in a short circuit between the column and the line, at the intersection of which the key pressed is located.

When the user dials his confidential code, the latter is tested against that which is stored in the EEPROM memory. If the code is correctly composed (equality), the microcontroller activates an LED witness (7). From this moment, pressing a key results in the short-circuiting of the corresponding line and column at the output of the key (CRSWITCH output) (6) to the telephone set (dialing circuit) .

 If the code entered does not correspond to the one stored, the microcontroller blocks the CRSWITCH circuit and any key pressed is then ignored by the set.

 The practical use of the electronic key is as follows:

 1. Dialing a number with a maximum of four digits:

 The user could use urgent communications (rescue, firefighters, etc.), or communications within the same organization. Since such telephone numbers vary from 2 to 4 digits, communication is possible without having to enter the confidential code.

 2. Dialing a number of five or more digits:

 The electronic key as delivered, has the following co-confidential code (000),

 a) lift the handset (the connection tone is obtained),

 b) dial the code as follows: * 000

 (the asterisk indicates the beginning of the code, the three digits 000 indicate the code).

 At this time, the indicator LED lights up, indicating that the code that has been entered corresponds to the confidential code.

 Therefore, any communication is possible.

 Example:

 To call a correspondent whose number is 49-73-15-83. the entire number will be: * 00049731583.

 3. Change of code:

 To change the code, which is in the case described (000), code (739) for example, we have to execute the following operations: a) lift the handset,

 b) dial the old code (* 000), the LED indicator lights up,

 c) dial the new code (* 739),

 d) hang up the handset.

 From now on, to be able to communicate, the new code (739) will have to be dialed.

 4. Permanent operation:

If one wishes to make successive calls without having to dial the code before each call, it will suffice to dial a sub-code after the stored confidential code. To do so:

 a) lift the handset,

 b) dial the memorized confidential code, the LED indicator lights up, c) dial the sub-code, which is (##),

 d) hang up the handset, the indicator LED goes off.

 At this time, it is possible to obtain communications without using the confidential code.

 This being;

 a) lift the handset, the indicator LED lights up,

 b) dial the number of your correspondent (example: 49-73-15-83).

 If you wish to remove the permanent operation, you perform the following operations:

 a) lift the handset, the indicator LED lights up,

 b) dial the sub-code (##), the LED indicator goes off,

 c) hang up the handset, the set is again protected.

 At this time, if the handset is lifted, the indicator LED remains off, this reminds that it is not possible to dial numbers greater than four digits.

GLOSSARY:

LED: Light-Emitting Diode.

 CRSWITCH: Crosspoint Switch.

EEPROM: Electrically erasable Programmable Read Only Memory.

Claims

R E V E N D I C A T I O N S

1) Electronic key characterized by the fact that it is made up of:

 a) a memory (5) in which the confidential code and the operating mode can be modified and stored.

 b) a croswitch circuit (6) which simulates the operation of the keyboard at the input of the telephone station dialing circuit.

 c) a microcontroller circuit (4) which controls the croswitch (6), memory management (5) and the keyboard input.

 d) an LED (7) indicating the operating status of the electronic key.

 2) Electronic key according to claim 1, characterized in that the confidential code is located in the memory and can be updated as many times as desired, therefore erasable (erasable type memory).

 3) Electronic key according to claim 1 and 2, characterized in that the confidential code is kept in the memory independent of the opening or closing of the handset and in the absence of any other energy, therefore autonomous of the EEPROM type (memory EEPROM type).

 4) Electronic key according to claim 1, characterized in that it is equipped with a microcontroller whose program contained in its own memory performs the following operations:

 a) detection of a key pressed.

 b) comparison of the memorized confidential code with that entered by the user when the latter wants to make a communication.

 c) recognition of a sub-code which makes it possible to activate or deactivate the protection function.

 d) control of memory writing and reading.

 e) croswitch control.

 5) Electronic key according to claim 1, characterized in that the croswitch allows the control of a numbering circuit independently of the latter that it is a decimal numbering circuit or a numbering circuit with multifrequency.

6) Electronic key according to claim 1 and 4, characterized in that the change of the confidential code in the memory (5) is managed by the program contained in the memory of the microcontroller. This program ensures the process of modifying the confidential code and this at the request of the user via the keyboard of the telephone set. 7) Electronic key according to claim 1,2,3 and 6, characterized in that the means allowing the subscriber to dial or modify his confidential code is the ordinary keyboard of the telephone set.

 8) Electronic key according to claim 1, characterized in that the starting of the electronic key is done by the detection of the current of the telephone line different from zero.

 9) Electronic key according to claim 1, characterized in that the supply of all the circuits constituting this device is the same as that which supplies the circuits of the telephone set.