KR930003478B1 - Interface circuit and method for fax - Google Patents

Abstract

The circuit enables built-in facsimile to be dialed using 10 numeric keys of a control panel when power is on and off. It includes relays (12,14) for switching a telephone line to facsimile or telephone, a modem (18) for converting Tx/Rx signals, a ringer circuit (22) for generating audible ring signal, a dialer circuit (26) for selecting one of the dial pulse and MF signal, a remote control transformer (32) for transmitting the DTMF signal to the modem (18), and a central processing unit (34) for controlling the facsimile.

Description

Public telephone network interface circuit and method for dialing in case of power failure in built-in fax machine

1 is a conventional block diagram.

2 is a block diagram according to the present invention.

3 is a concrete circuit diagram of the dialer circuit 26 of FIG.

4 is a control function flow chart according to the present invention.

* Explanation of symbols for main parts of the drawings

12,14 Relay 16,32 Transformer

18: modem 20: hook switch

22: ringer circuit 24: operation panel

26 dialer circuit 28 call circuit

30: bridge diode 34: CPU

The present invention relates to a public telephone network (PSTN) interface circuit and method capable of dialing in the event of a power failure in a telephone-embedded facsimile, and in particular, comprising a 10-digit keypad and a 10-digit keypad for a built-in telephone. The present invention relates to an interface circuit and a method capable of dialing during power failure, in which a 10-digit key on the operation panel of the facsimile is commonly used at the time of power failure and power "on".

The use of fax machines with built-in telephones is common. The telephone-integrated facsimile telephone call is made by scanning and dialing a 10-digit key input of a control panel from a central processing unit (hereinafter referred to as "CPU") in a power "on" state. In the case of power failure, dialing by a dialer circuit is made according to the 10-digit key input of the built-in telephone.

The telephone interface circuit of the telephone-integrated facsimile is configured as shown in the first diagram and has a redundancy structure to perform a telephone function by inputting 10 digits of the operation panel 24 and the keypad 38 according to the power supply state.

In the circuit of FIG. 1, the dialing operation operates in two cases, when the power is "on" and when the power is "off", i.

First, when the power is “on”, when the user presses a 10-digit key on the fax's control panel 24 during hook-on dialing or fuku off-dialing, the CPU 34 scans the keystrokes according to the user's option setting. Pulse dialing is performed by the pulse dialer 36 or the modem 18 is controlled to perform DTMP (Dual Tone Multi Frequency) dialing.

In the second correction, the dialer circuit 26 becomes active in the hook-on state, and is operated by the call power supplied from the exchange through the tip terminal T and the ring terminal R of the telephone line. Dialing is performed according to the 10-digit key input of the keypad 38. At this time, the dialer circuit 26 transmits a dial signal in the form of a dial pulse or DTMF to the telephone line in accordance with the user's option setting as in the case of the "on" power supply.

The conventional dialing method is capable of dialing by using an operation panel 24 having a 10-digit key having a structure capable of kissing scan by a CPU when the power is "on", and another 10-digit keypad during power failure. By designing in a dual structure, the CPU is down during power failure, and only the dialer integrated circuit (IC) chip in the dial circuit 26 is activated to enable dialing.

As described above, the conventional dialing method has a dual path for dialing when the power is "on" and when the power is "off", i.e., when the power is out. The city has a circuit configuration using a 10-digit keypad directly connected to the dialer IC chip, so that the dialer circuit and the 10-digit keypad have two parts, which complicates the circuit and increases the cost due to the large number of components.

Accordingly, an object of the present invention is to provide an interface circuit and method for dialing a telephone built-in facsimile in case of power failure, and to dial when power is turned “on” and power “off” using only 10-digit keys of an operation panel. In providing.

According to another object of the present invention, when dialing in the form of dial pulse or DTMF signal according to option setting in dialer circuit in case of power failure, according to 10-digit key input of operation panel when power is turned on By providing DTMF signal generated from dialer circuit through modem path for remote control through modem path, it provides interface circuit and method that can dial in case of power failure that CPU can recognize and perform operation according to key input. have.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram according to the present invention, which is connected to a tip terminal T and a ring terminal R of a telephone line and interlocked by a predetermined control to selectively switch the connection of the telephone line to a facsimile and a telephone ( 12 and 14, an impedance matching transformer 16 for transmitting and receiving a signal connected to the telephone line when faxing by switching between the relays 12 and 14, and by predetermined control Modem 18 which modulates and demodulates the transmitted and received signals through the transformer 16 and transmits and decodes DTMF signals, a hook switch 20 which is switched by a user's operation, and switching of the relays 12 and 14. Work input terminal is connected to the tip terminal T through the hook switch 20, and a type force terminal is connected to the ring terminal R when the telephone is switched to the telephone by the hook. Auded by ring signal input in ON state ible) a ringer circuit 22 for generating a ring signal, a plurality of function keys and 10 numeric keys for controlling the facsimile operation, and an operation panel 24 for outputting key data according to the key operation; A dialer circuit 26 for selectively outputting dial pulses and MF signals according to the 10-digit key input of the panel 24 according to option settings, and connected to an output terminal of the dialer circuit 26 to perform a call function. A bridge diode 30 connected between the telephone line and the telephone circuit through the hook switch 20 when the telephone circuit is switched to the telephone by the switching of the relays 12 and 14; One side is connected to the call circuit through the bridge diode 30 and the other side is connected to the modem 18 so that the remote relay 12, 14 is input for the remote control when the telephone line is switched over. DTMF signal The remote control transformer 32 for transmitting to the existing modem 18, the operation of the relays 12 and 14, the modem 18 and the dialer circuit 26, and the operation panel 24 And a CPU 34 for performing a function according to decoding data of a DTMF signal according to a 10-key input entered through the modem 18 and a facsimile function of the facsimile.

FIG. 3 is a detailed circuit diagram of the dialer circuit 26 in FIG. 2, and the power terminal VDD and the ground terminal GND are connected to the power supply voltage Vcc and the sub-power supply voltage Vss through the communication circuit 28. ) Are connected to each other, and the input state to the option input terminal T1, the key input data (X1-X3) of the column of the 10-digit key matrix of the operation panel 24, and the key input data of the row (row). A dialer IC 52 for inputting (Y1-Y4) to the column input terminals C1-C3 and the row input terminals R1-R4, respectively, to selectively output DTMF signals and dial pulses to the call circuit 28; The output side is connected between the power supply voltage Vcc and the negative power supply voltage Vss through the resistor 56, and the input side is connected to the input / output (I / O) port of the CPU 34 so that the CPU 34 A photo coupler 58 operated by the control, and one side is connected to the option input terminal T2 of the dialer IC 52, and is used for option operation. It is composed of an option selection switch 54 which is switched accordingly and is selectively connected to the power supply voltage Vcc and the sub power supply voltage Vss through the resistor 56.

The configuration of FIG. 3 shows only a part of the dialing function, and the dialer IC 52 may be used by Motorola and MC145412.

4 is a flow chart of a control function according to the present invention, in which a dialing mode checking step of checking whether a dialing mode key is entered when a function key is input, and the system is initialized to a dialing state temporarily dialed mode to be dialed by the dialer circuit 26. A dialing operation setting step and a non-dialing operation setting process of initializing the system to a non-dialing state in the non-dialing mode to perform a function according to a key input from an operation panel through a modem.

The flowchart of FIG. 4 is a flowchart of execution of the CPU 34 of FIG. 2 upon powering "on".

Hereinafter, operation examples of FIGS. 2 to 4 according to the present invention will be described in detail.

First, the photocoupler 58 of FIG. 3 has the active transistor "active on" or "active off" depending on the output state of the CPU 34 of FIG. 2, and the output "high" of the CPU 34 when the facsimile is in the dial mode. "On" by "" and "off" by "low" in non-dial mode.

When the option selection switch 54 is connected to the first terminal 101 by the user's operation, the dialing IC 52 enters the dial pulse mode, and when connected to the second terminal 102, the DTMF signal mode is entered. At this time, even if the option selection switch 54 is connected to the first terminal 101, if the fax is in the dialing mode, the porter coupler 58 is "on" under the control of the CPU 3, and the dialer IC ( Since " low " is input to the option input terminal P / T3 of 52), the dialer IC 52 outputs a DTMF signal in response to a key input. Therefore, the dialing IC 52 outputs the dial pulse only when the option selector switch 54 is connected to the first terminal 101 and the photocoupler 58 is " off "

In other words, unlike the dialing method of the conventional facsimile, regardless of the "on" or "off" of the power supply, the telephone number by the 10-digit key input of the operation panel 24 without using a pulse dialer or a modem is dialed IC 52. And dials the telephone line according to the manner selected by the option selection switch 54.

As described above, it is possible to unify the duplex structure of the keypad, but the function of dialing a 10-digit key does not allow the CPU 345 to input a number for performing a fax function. To solve this problem, the MF signal generated by the dialer circuit 25 is fed back to the modem 18 having the DTMF signal detection function by using a conventional remote control circuit path. When the digit number by key operation is transmitted to the CPU 34 for processing, the same effect as the method of scanning the digit number into the input / output port of the CPU 34 in the conventional dialing method can be obtained. That is, numerical information is inputted to the CPU 34 through the call circuit 25, the bridge diode 30, the remote control transformer 32, and the modem 18 through the output MF signal of the dialer circuit 26.

Here, the remote control transformer 32 inputs a DTMF signal input through a telephone line to a modem 18 according to a key operation of a 10-digit keypad of a telephone to remotely control a facsimile by a user calling from outside. It is to let.

On the other hand, when the power is "on", the control function of the CPU 34 according to the present invention is performed as shown in FIG. Check if dialing mode key is input in step (A2) when inputting function key in 24). At this time, the system is initialized to the dialing state in step A3. Accordingly, as described above, dialing by a dial pulse or DTMF signal by the dialer IC 52 of the dialer circuit 26 is performed.

When it is not in the dialing mode in step (A2), it initializes to the non-dialing state in step (A4) and performs a function according to a function key input in step (A5). In other words, the CPU 34 "turns on" the photocoupler 54 of FIG. 3 to perform the fax function in non-dialing mode so that the DTMF signal is transmitted regardless of the mode selected by the user of the dialer IC 52 for dialing. By causing the DTMF signal of the number according to the user's key operation to be generated in the dialer IC 52, the DTMF signal is fed back to the above-mentioned remote control path and inputted to the modem 18 with DTMF decoding function. The same effect as that scanned by the CPU 34 can be obtained with the 10-digit keys of the operation panel 24.

On the other hand, when the power is "off", the dialer IC 52 performs dial pulse or DTMF signal dialing in accordance with the 10-digit key input of the operation panel 24. As described above, the present invention is capable of dialing irrespective of “on” or “off” of the system power supply, and the keypad can be unified with the 10-digit keypad of the operation panel, and the dialing burden of the software can be reduced.

In addition, there is no need for a conventional pulse dialer, and there is an advantage in that the input / output port of the CPU connected to the operation panel can be reduced.

Claims (3)

A public telephone network interface circuit capable of dialing in case of a power failure in a built-in telephone of a telephone, which is connected to a tip terminal T and a ring terminal R of a telephone line and interlocked by a predetermined control to select the connection of the telephone line as a facsimile and a telephone. Relays 12 and 14 for switching, an impedance matching transformer 16 for efficiently transmitting and receiving a signal connected to the telephone line when switching to fax by switching between the relays 12 and 14, and predetermined control A modem 18 for transmitting and decoding a DTMF signal by modulating and demodulating the transmitted / received signal through the transformer 16, a hook switch 20 switched by a user's operation, and the relays 12, 14 When switching to a telephone by switching of), one input terminal is connected to the tip terminal (T) through the hook switch 20 and a type force terminal is connected to the ring terminal (R) so that the hook switch (20) A ringer circuit 22 for generating an audible ring signal by a ring signal input in a "hook on" state, and a plurality of function keys and 10 numeric keys for controlling the facsimile operation are provided. An operation panel 24 for outputting, a dialer circuit 26 for selectively outputting dial pulses and DTMF signals according to the 10-digit key input of the operation panel 24 according to option settings, and the dialer circuit 26 A telephone circuit connected to an output terminal and performing a telephone call function, and the telephone line and the telephone circuit through the hook switch 20 when the telephone is switched over by switching of the relays 12 and 14; ) Is connected between the bridge diode 30 and one side is connected to the call circuit through the bridge diode 30 and the other side is connected to the modem 18 to transfer to the telephone of the relays 12 and 14. The bridge diode 3 A remote control transformer 32, the relays 12, 14 and the modem 18 for efficient transmission of a DTMF signal input through 0) and a DTMF signal for remote control inputted from the telephone line; It controls the operation of the dialer circuit 26 and performs a function according to the decoding data of the DTMF signal according to the function key input of the operation panel 24 and the 10-digit key input input through the modem 18, An interface circuit capable of dialing in the event of a power failure in a telephone-embedded fax machine comprising a CPU (34) which performs the functions of the fax. The power supply terminal (VDD) and ground terminal (GND) are connected to the power supply voltage (Vcc) and the negative power supply voltage (Vss) through the telephone circuit (28), respectively. The input state to the terminal P / T, the key input data (X1-X3) of the column of the 10-digit key matrix of the operation panel 24, and the key input data (Y1-Y4) of the row are respectively the column input terminals C1-. C3) and the dialer IC 52 for inputting the DTMF signal and the dial pulse to the communication circuit 28 selectively by inputting to the row input terminals R1-R4, and the power supply voltage through the resistor 56 at the output side. A photocoupler 58 connected between Vcc) and the negative power supply voltage Vss and having an input side connected to an input / output (I / O) port of the CPU 34 and operated under control of the CPU 34; One side is connected to the option input terminal P / T of the dialer IC 52 and switched according to an option operation so that the other side is connected to the power supply voltage Vcc and the negative power supply voltage through the resistor 56. An interface circuit capable of dialing in case of a power failure in a telephone-embedded facsimile machine, characterized in that it comprises an option selection switch (54) selectively connected to Vss). Relays 12 and 14, transformer 16, modem 18, hookswitch 20, ringer circuit 22, operation panel 24, dialer circuit 26, and call circuit A power supply "on" state in a public telephone network interface system capable of dialing in case of power failure in a telephone-embedded fax machine having a 28, a bridge diode 30, a remote control transformer 32, and a CPU 34. A dialing mode checking step of checking whether the CPU 34 dials a dialing mode key when the enable key is input from the operation panel, and setting a dialing operation to initialize the system to a dialing state temporarily by dialing mode to allow dialing by the dialer circuit. And a non-dialing operation setting step of initializing the system to a non-dialing state in the non-dialing mode and performing a function according to a key input from the operation panel through the modem. Power off " off " and power off " off " operation in which the dialing circuit is dialed by the dialing circuit according to a key input from the operation panel in the power off state. Possible interface method.