KR890003763B1 - Automatic answer and automatic dialing method and circuit in mo/demodulation - Google Patents

Abstract

The modem with automatic answering/dialing function and dual speed of 300/1200 bPS includes an I/O circuit (1), a CPU (2) for scrambling/ discrambling the data with a control signal, a converting filter (3) for determining the band pass frequency according to the modulation and transmission speeds of the data, a MODEM circuit (4) for modulating/demodulating the signal, a control counter (5) for controlling the data of 1200 bPS, a hybrid-demodem circuit (6) for controlling the gain of the data automatically, and a data access arrangement circuit (7) for linking the MODEM and the telephone line.

Description

Auto Answer / Auto Dial Method and Circuit in Modem

1 is a basic schematic diagram of the demodulator.

2 is a block diagram according to the present invention.

3 is a detailed circuit diagram of FIG. 2 in accordance with the present invention.

4 is an automatic dial flow chart according to the present invention.

5 is an automatic response flow chart according to the present invention.

* Explanation of symbols for main parts of the drawings

1: I / O 2: Central control unit

3: conversion filter unit 4: modem unit

5: control counter part 6: hybrid demodulator part

7: DAA part

TECHNICAL FIELD The present invention relates to auto dialing and auto answer in a modem, and in particular, an auto answer and an auto dial circuit of a modem that can be used for low or medium speed data transmission of 300/1200 BPS. And to a method.

In general, a modem is a modulation and demodulation device that modulates and transmits digital data through a computer or various terminals into an analog signal, and in a remote modem, demodulates and receives the analog signal back into a digital signal. Full-duplex, half-duplex (point-to-point) on wire tracks, point-to-point on 4-wire tracks, or multipoint configurations Half Duplex) Using synchronous / asynchronous method, data communication is possible at high speed within a certain distance.

The modem, that is, the demodulator, is largely divided into a transmitter and a receiver.

That is, the dotted part is divided into the transmitter T and the receiver R. In the transmission, the digital signal from the terminal is scrambled by the data encoder (central processor), and then modulated at the carrier frequency by the modulator. It is transformed into an analog signal form and exits the transmission line through the limiting filter.

In the limiting filter, its shape varies according to a modulation method or a communication speed, and the amplifier amplifies the amplitude of a transmission signal to a desired size and sends it to a communication line through a transformer. The receiver passes the analog signal from the communication line through the band-limited filter within the desired frequency band and then enters the automatic gain controller. The analog signal, which is made of a suitable signal size and input to the demodulator, is converted into a digital signal by demodulation. It is then descrambled in the data decode (central processing section), reduced to the original data and received at the terminal. Since the transmission clock source, the clock source, and the phase compensation circuit of the dotted line block of FIG. 1, which are not described above, are used only in the case of the synchronous modulator, a special description is omitted.

Modulators are classified into synchronous and asynchronous according to the synchronous method. Generally, the asynchronous demodulator is classified as asynchronous when 1200 BPS or less, and synchronous when more than 1BPS. Frequency shift modulation (FSK), amplitude shift modulation (ASK), Phase shift keying (PSK) is commonly used, but V.21 in the CCITT (Europe) table and 200 BPS asynchronous by FSK modulation in Bell (US) 103/113 series demodulators are used. The V.22, Bell 202, and 212 series have been widely applied to 1200BPS synchronous data transmission using two-phase modulation (DPSK).

Therefore, according to the Bell series or CCITT standard, only a single transmission rate was used as a characteristic for each type. As a result, when the computer is trying to operate the demodulator, it is uneconomical and unreasonable to add the demodulator as many as the mode of data transmission rate to be transmitted.

In addition, although the leased line and the exchange line are different depending on the model of each manufacturer, the exchange line is divided according to the possession of the originate and answer functions. In the case of the leased line, there are two functions: call and answer. All this was possible.

Here, briefly describe the call / answer function that has been used conventionally, the manual call origination checks that all the push buttons are not pressed, and then pushes the Answer pushbutton to the Origin mode. Release. The data display (LED) is on and the "DATA / TALK" button is turned off and the telephone handset is picked up to dial the desired party. If the operator of the other party does not hear a response signal within a predetermined time after the dialing, the call corresponds to a request for data transmission. When the caller hears a response signal, the "DATA / TALK" and CO (Central Pffice) indicators (LEDs) are turned on, and a data transmission line is formed. If the configuration of the transmission line in the above process (Fail) Fail Abbott (AABORT) timer is operated, in this case within a few seconds to switch to the data mode. If you do not switch, the line is automatically cut off. On the other hand, when the data communication is finished, lift the handset to switch the "DATA / TALK" selection pushbutton to TALK mode and switch to "DATA / TALK" mode by the DTR (Data Terminal Ready) off signal from the terminal (DTE). .

The response operation verifies that not all pushbuttons are pressed, and places the answer (ANS) pushbutton in "ANS" mode. When the next DATA indicator (LED) is on, push the "DATA / TALK" selection pushbutton to turn it off. At this time, when the phone rings, pick up the handset, talk to the caller, inform the other party that the caller is ready for data communication, and switch the "DATA / TALK" pushbutton to "DATA" mode. At this time, the data display device LED is turned on. When the other party receives the response signal and switches to the "DATA" mode, the display device LED is turned on for the "CO" display, and the data communication line is configured. At the end of the data communication with the handset, pick up the handset and push the "DATA / TALK" selection pushbutton to dial "TALK" mode. If you have turned on the ABORT timer when you do not need to talk to the other party here, the caller will switch to "TALK" mode after a few seconds if the caller finishes sending data and switches the call modem to "TALK" mode. The line is cut off.

As described above, the origination and answer must be re-manufactured by manual, which leads to inconvenience of the user and frequent misoperation due to the inconvenience of operation. There was a drawback of low reliability and high failure rate. Accordingly, an object of the present invention is to provide a modem that can be used at 300BPS or 1200BPS speed.

Another object of the present invention is to provide a circuit that can reduce the number of modems on the computer because the response speed is automatically determined according to which speed is selected by the caller because it has two transmission speeds.

Still another object of the present invention is to provide a method for automatically handling a response function and a dialing function for a 300BPS or 1200BPS combined modem.

Therefore, the present invention for performing the above object is an input / output unit in which transmission and reception data is transmitted from a computer or a terminal (DTE) by RS-232C connection and an indication according to each operation is displayed, Automatic baud of 300BPS / 1200BPS is determined from the output part according to the designated baud rate, and it has a memory device and a tone generator so that the automatic dial signal is generated according to the program and the control signal is generated to perform the auto response function. Another transmission / reception control signal and a data signal are generated at / 1200BPS to scramble / descramble the transmission / reception information, and to convert the scrambled signal from the central controller into an analog signal and to the control signal of the central controller. After determining the transmission band frequency by band band filtering and amplifying it according to 300BPS / 1200BPS transmission speed It reproduces normal analog signal and outputs analog signal converted by PSK (1200BPS) modulation by signal generated from the central controller signal in call mode, and dialing and response theory generated by the central controller is output. And a conversion filter unit controlled by the central control unit output signal to pass a 300BPS communication frequency and having a filtering function within a corresponding band for transmission data, and converting the input signal from the input / output unit to the 300BPS transmission rate by FSK modulation. A modem unit having a modulation / demodulation function according to the present invention; It has a function and filters the control signal according to the transmission and reception of the control counter unit and the output of the conversion filter unit Hybrid demodulator unit that demodulates and transmits the gain control of the received signal and transmits the function according to the mode so that the user can recognize the ring signal. Characterized in that it is composed of a DAA unit for driving the dialing relay.

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, in which data input and output from a terminal (not shown) is transmitted and received by RS-232C connection, and each operation state can be distinguished according to the transmission and reception of the data. The automatic baud of 300BPS / 1200BPS is determined according to the input / output unit 1 displayed on the display unit and the transmission speed designated by the input / output unit 1, and the program includes a storage device and a tone generator. A control signal for generating an automatic dial signal and an automatic response function is generated, and the central control unit 2 scrambles / descrambles the data according to 300 BPS / 1200 BPS by the control signal, and the central control unit 2 Converts the scrambled signal into an analog signal, modulates data by the control signal generated by the central controller 2, and determines a band pass frequency according to the transmission rate, A conversion filter unit 3 for amplifying the filtered signal of the transmission data within an overfrequency, and a modem unit for modulating and demodulating the transmission / reception data input and output from the input / output unit 1 according to the 300BPS transmission rate by the FSK modulation method. (4), a control counter 5 which generates a predetermined frequency by receiving a clock signal generated by the clock generator of the central controller 2 and generates a control clock for 1200 BPS transmission and reception, a reception filtering function and It has a speaker driving and demodulation function, and receives and filters the data transmitted and received from the conversion filter unit 3 according to the control signals output from the control counter 5 and the central controller 2. And a hybrid demodulator unit 6 which transmits and outputs a process of operation according to each function to a speaker and automatically adjusts gain (AGC: Auto Gain Control) for transmission and reception data, It provides the ring signal to the central control unit 2 through the line (L1), receives the input and output signals from the hybrid demodulator unit (6), the modem and the telephone line of the other side is connected to drive the pulse dial relay relay and ring signal Is detected, and a data access arrangement (Data Access Arrangement: hereinafter referred to as "DAA") 7 is provided.

3 is a detailed circuit diagram of FIG. 2 according to the present invention, wherein the input / output unit 1 is connected to a data terminal (DTE) by a RS-232C method and transmits and receives data. An input unit 10, a display unit 20 for displaying an operation state different from the operation of the modem, and a latch 150 for latching reception data and display mode data according to a reception or transmission process.

The central control unit 2 is composed of a memory area control unit and a status function to perform automatic answering and dialing and programming according to each mode to output control signals to each unit, and to scramble / descramble the transmission and reception data signals. (Scramble / Descramble) and a central processing unit (30) for controlling the transmission and reception speed and conversion by embedding an asynchronous transmitter and receiver (UART), and for supplying a clock signal to the central processing unit (30) and each part The central processing unit includes a clock generator 50 for generating a signal, a phone number embedded ROM 40 for embedding a telephone number of a customer, and a dial and command signal input from the transmission / reception input unit 10. The device 30 consists of a tone generator 70 which processes to select the tone / pulse and the built-in telephone number to generate a tone signal when the tone is a tone.

The conversion filter unit 3 is controlled by the central processing unit 3 and the D / A converter 80 for converting the digital signal scrambled by the central processing unit 30 into an analog signal during 1200 BPS transmission. Since the analog signal converted by the D / A converter 80 is not a complete analog waveform, it is composed of a band pass filter circuit 100 for filtering to be a normal analog signal.

The modem unit 4 uses the same reference numerals as those in FIG. 2 as a modem integrated circuit which modulates and demodulates the FSK modulation method at the time of 300BPS transmission and reception.

The control counter 5 counts the pulse signal generated from the clock generator 50 at the time of 1200 BPS transmission and reception to make a predetermined frequency, and generates a counter clock 60 for data transmission and reception. The control unit receives the control signal from the central processing unit 30 through the lines 33 and 35 to control the modem unit 4 by a selection signal to perform another control for 300 BPS transmission, and to control the counter circuit 60. And a demultiplexer (160, 170) for controlling the carrier frequency to generate a different state in the 1200BPS data transmission, and to transmit the state according to the data transmission to the central processing unit (30).

The DAA unit 1 uses the same reference numeral as that of FIG. 2 as a DAA to which a telephone line and a modem are connected, and provides a ring signal through a line L1. The hybrid demodulator 6 includes a speaker driver 120 which generates a negative state of each tone signal generated from dialing to the other modem, and 2-to-4 hybrid and demomode are built in. And input and output signals transmitted and received from the DAA unit 7, drive the speaker drive unit 120, and receive the data corresponding to the 1200 BPS speed by the signal generated by the counter circuit 60. A demodulator and a hybrid 130 demodulated and descrambled by the central processing unit (hereinafter, referred to as a "CPU") 30, and a received signal input from the band pass filter 100 to the demodulator and the hybrid. Automatic gain control unit 140 is input through the 130 to automatically adjust the gain to a suitable size and at the same time to remove the noise input to the demodulator of the demodulator and hybrid 130 to demodulate The.

Referring to the configuration of FIG. 3 described above in detail with reference to FIG. 2, the input / output unit 1 has an output terminal of the latch 150 connected to a receiving line 12 of a transmission / reception input unit 10 connected to a terminal side, and the latch The display unit 20 is connected to the output line 13 of 150.

The central control unit 2 is connected to the transmission line 11 of the transmission and reception input unit 10 and the transmission terminal of the CPU 30, the output terminal of the tone generator 70 and the clock generator 50 is an output port of the CPU 30 And the ROM 40 is connected to the CPU 30 so that the stored phone number can be used under the control of the CPU 30. In the conversion filter unit 3, a D / A converter 80 is connected to an output terminal of the CPU 30, and a band pass filter 100 is connected to the D / A converter 80.

The modem unit 4 and the DAA unit 7 use the same reference numerals as those in FIG. 2, and the control counter unit 5 has a predetermined carrier for 1200 BPS data transmission for counting signals output from the clock generator 50. The counter circuit 60 generating the frequency and the data output from the CPU 30 are input through the line 33 and demultiplexed to control the 300BPS data transmission of the modem unit 4 and the counter circuit 60. A demultiplexer (DMUX) 60 for outputting a signal for determining a counting mode for generating a carrier frequency in accordance with 1200BPS data transmission and a data output from the CPU 30 are input through a line 35 to demodulate the modem. And a multiplexer (MUX) 70 which multiplexes data received through the hybrid 130 and inputs the same to the CPU 30.

The demodulator and hybrid 130 of the hybrid demodulator unit 6 are connected to the input / output terminals of the conversion filter unit 3, the modem unit 4, and the control counter 5 to transmit data and simultaneously receive data. Demodulation, and the gain control unit 140 connected to the demodulator and the hybrid 130 to adjust the other gain in the transmission and reception of the transmission and reception data, the speaker driver 120 is configured to display the data transmission state as a negative.

4 is an auto dial flow chart according to the present invention, which receives a "AT" command to determine a data transmission speed and a format, and checks input of command data corresponding to an electronic / mechanical dial mode. A second process of turning on a relay and driving a speaker when the electronic / mechanical method is checked in the first process, making a corresponding dial according to the pulse / tone dial mode in the first process, and outputting a standby carrier signal; Waiting for a predetermined time when there is no standby carrier in the second process, the relay is turned off, and when the standby carrier is present, a third process of checking whether 1200 BPS is applied; and when the 1200 BPS is performed in the third process, scrambled data is transmitted and the connection state is displayed. If it is not 1200BPS, it uses the low channel of the call and sends a mark ("high") to indicate the connection status and go online. It is.

5 is an auto answer flow chart according to the present invention, which determines a data transmission speed and format, checks whether an auto-responder is present, and displays a different state in the auto-response when the auto-answer is performed in the first step. A second step of reducing the count register value according to the ring signal input and sending out a carrier corresponding to the response theory by checking the "A" digit input when it is not an automatic response; and sending out the second step. A third step of receiving a carrier and checking whether the transmission mode is 1200 BPS when it corresponds to 1200 BPS, a fourth step of checking and accessing 1270 HZ corresponding to a mark tone when the 1200 BPS transmission mode is not in the third step; In step 3, check 1200BPS scrambled mark in 1200BPS transmission mode, wait for a predetermined time when there is no mark, and then carry out no carry when there is no mark. To play, and issues a call to the mark carrier frequency 2400HZ when there is a 1200BPS scrambled mark comprises a fifth step of displaying the connection state.

Therefore, when the embodiment of the present invention is described in detail with reference to 2-5, the call operation (Orgination Operation) is a keyboard of the terminal (DTE) without using the button key of the telephone for dialing to the other party in the ready state for operation. I want to dial by inputting the other party's phone number with a predetermined command through. The dialed data is driven through a line drive of an RS-232C transmission method and input to the CPU 30 through the transmission / reception input unit 10.

In addition, when speed dialing, the CPU 30 controls the CPU 30 to give a fixed address (Adress) of the phone number built-in Tom 40, and then dials the number from the ROM 40 and dials each program. At the same time, a default value is transferred from the memory on the ROM 40 to the random area of the CPU 30 to receive the data corresponding to the command and the dial number. Control transmission.

Therefore, referring to the auto dial function according to the auto dial flow chart of FIG. 4, when the tone and pulse dialing command (ATDT / P) is keyed in via the terminal DTE, the transmission / reception input unit 10 is transmitted through the RS-232C transmission line. Is driven and input to the CPU 30. The CPU 30 first determines the data transfer baud and the data format of the data to be transmitted, based on the input "AT" instruction data, and checks "D" for dialing. If it is not "D", the next command check routine is executed. However, when "D" for telephone number dialing, the CPU 30 checks whether "P" is for pulse dialing.

Here, when "D", search for "Do you have the next number?" At this time, when the next instruction routine is checked, but when there is a telephone number, the relay driving unit of the DAA unit 7 is driven on through the demodulator and the hybrid 130, and the speaker driving unit (through the modem and the hybrid 130) ( 120, the user is notified of the result signal of the procedure for performing the dialing. After the predetermined time delay, the relay driver of the DAA unit 7 is turned off. On the other hand, when it is not "P", the CPU 30 checks whether it is "T" for the tone dial and checks whether there is a next number when it is "T". Here CPU 30 checks whether pulse " P " is not " T " to select a mode for tone and pulse dialing. If there is no next number or no pulse, the command check routine and pulse dialing should be executed.When the next number is input or pulse dialing, the relay between the speaker driver 120 and the DAA unit 7 turns on and the pulse is delayed after 1 second. Dialed by / tone.

For example, during pulse dialing, the relay of the DAA unit 7 is turned on / off according to the dial digit pulse through the demodulator and the hybrid 130 to transmit a dialing signal, and the demodulator and the hybrid 130 are dialed during tone dialing. Through the relay of the DAA unit 7 through the signal generated by the tone generator 70 is sent through the relay is turned on is the tone dialing. In response, a Mark of response theory ("high"), which is input through the modem unit 4 from the high channel on the response side for 30 seconds, waits for the reception of the carrier signal of 2225HZ.

At this time, if more than 30 seconds without the carrier is considered that there is no carrier to display the state by driving the display unit 20 through the latch 150 to inform the state without the carrier after the DAA unit (7) Turn off the relay. After that, it returns to the next initial check routine, and when there is a carrier, when the data transmission rate is not 1200 BPS, the modem transmits the 1270HZ frequency corresponding to the macron through the modem unit 4 using a low channel when calling. The relationship is driven through the latch 150 to display the state by displaying the state and bring the transmission line online. Then, at 1200 BPS, the CPU 30 sends a control signal to the multiplexer 170 through the line 35 to receive the received data by selection, checks the result at the CPU 30, and responds with scrambled data. The CPU 30 then checks whether or not the scrambled data has been entered. When the scramble data is input, the display according to the connection is driven by the speaker driving unit 120 through the demodulator and the hybrid 130, and output to the display unit 20 through the latch 150. It is transmitted to the transmission line online through the DAA unit 7 and waits for a predetermined time when the scramble data is not input. Therefore, after the online connection is made, the automatic response is performed by the automatic response flowchart of FIG. The software is automatically loaded with the default value in the memory area at the same time as the system is on. The bow speed and the format of the CPU 30 of the central controller 2 are changed by the "AT" signal input through the keyboard of the terminal. Is determined, and then it is checked whether it is an Auto Answer. In the case of the automatic response, the display unit 20 displays the state "AA" through the latch 150 and searches whether the call signal is input from the DAA unit 7.

)의 설정값을 감소(Decremant)시켜

일 때 CPU(30)에서 응답론에 해당하는 주파수 마크 2225HZ신호의 캐리어를 D/A변환기(80) 및 밴드패스필터(100)를 통해 보내며, 그리고 자동응답이 아닐때 "A"을 CPU(30)에서 검색한다. 여기서 "A"이라면 상기와 같이 마크 2225HZ의 캐리어를 모뎀부(4)로 보낸다. 그리고 CPU(30)가 멀티플렉서(170)를 제어하며 디모뎀 및 하이브리드(130)를 통해 입력되는 데이타를 받아 1200BPS속도에 해당하는 전송인가를 검색한다. 이때 1200BPS가 아닐때에는 마크 1270HZ인가를 검색하고, 여기서 1270HZ가 아닐때 30초가 넘으면 캐리어가 없는 상태가 되어 래치(150)를 통해 표시부(20)를 구동하여 상기 상태를 디스플레이 한다. 그러나 상기에서 마크 1270HZ일때는 모뎀부(4)가 접속되어 온라인이다. 한편 1200BPS일때 응답(Answer) 캐리어로 스트램블 마크 1200HZ를 멀티플렉서(170)를 통해 입력될때 CPU(30)에서 이를 체크하고, 아닐때 30초까지 기다린다. 상기 과정에서 이때 30초가 넘으면 캐리어가 없는 것으로 간주되어 래치(150)에 의해 표시부(20)의 구동으로 디스플레이되며, 스크램블 마크일때 호출(Origination) 캐리어 마크 2400HZ로 스크램블에 대한 신호를 보내어 접속을 알리는 신호로 표시부(20)의 구동시켜 이상태를 디스플레시킨다. 이어서 온라인되어 자동으로 응답신호가 들린다.이때 표시용 데이타가 래치(150)를 지나 표시부(20)에서 입력되어 데이타 모드로의 전환여부와 데아타 및 국선라인 상태를 알리기 위한 상태를 디스플레이되도록 함과 동시에 모드에 따른 데이타 송수신이 이루어진다. 모뎀의 1200BPS에서, 1200HZ, 2400HZ는 데이타의 송수신시 모뎀측에서 응답과 호출을 구분시키고자 하는 것으로 1200HZ가 응답 캐이러 주파수이고, 2400HZ가 호출 캐리어 주파수이다.Ring signal input frequency (S) when there is a call signal in the above process

Decrease the set value of

When the CPU 30 sends the carrier of the frequency mark 2225HZ signal corresponding to the response theory through the D / A converter 80 and the band pass filter 100, and when the automatic response is not "A" to the CPU (30) ). Here, if "A", the carrier of mark 2225HZ is sent to modem part 4 as mentioned above. Then, the CPU 30 controls the multiplexer 170 and receives data input through the demodulator and the hybrid 130 to search for transmission corresponding to a speed of 1200 BPS. At this time, if it is not 1200BPS, it is searched whether the mark is 1270HZ, and if it is not 1270HZ, if it is over 30 seconds, the carrier is not present and the display unit 20 is driven through the latch 150 to display the state. However, at the mark 1270HZ, the modem unit 4 is connected and online. On the other hand, when the 1200 (BPS) answer carrier (scramble mark 1200HZ) is input through the multiplexer 170, the CPU 30 checks this, otherwise waits up to 30 seconds. In the above process, if there is more than 30 seconds, the carrier is considered to be absent and displayed by the driving of the display unit 20 by the latch 150. When the scramble mark is a signal for scramble by sending a signal for scramble to the originating carrier mark 2400HZ The display unit 20 is driven to display this state. Subsequently, an online response signal is automatically heard. At this time, the display data is inputted from the display unit 20 through the latch 150 so as to display whether to switch to the data mode and to indicate the status of data or trunk line. At the same time, data transmission and reception according to the mode is performed. At 1200BPS of modem, 1200HZ and 2400HZ are to distinguish response and call from modem side when data is transmitted and received. 1200HZ is answer carrier frequency and 2400HZ is call carrier frequency.

In case of 1200BPS when data is transmitted from the calling party, a signal through the transmit / receive input unit 10 is input to the CPU 30 and scrambled by PSK modulation method at 1200BPS transmission rate, and the analog signal is input from the D / A converter 80. The switching unit of the band pass filter 100 is controlled by the control signal by the CPU 30 to determine the pass band of the response carrier frequency 1200HZ signal at the time of transmission. The D / A converter 80 converts the analog signal converted to D / A into a normal analog signal and generates a predetermined frequency generated by the counter circuit 60, which is generated according to the output of the demultiplexer 160. The counter mode is set to generate different carrier frequencies for the 1200 BPS data transmission of the circuit 60, and is input to the line 35 of the CPU 30 by the multiplexer 170. The predetermined output frequency of the counter circuit 60 is input to the demodulator and the hybrid 130 to transmit data in a dibit every predetermined period, and this signal is transmitted through the telephone line through the DAA unit 7. . In the case of 300BPS, the demultiplexer 160 demultiplexes the signal output through the line 32 according to the control signal output through the line 33 of the CPU 30 to control the modem unit 4 to transmit the signal. After the data inputted from the terminal of the receiving input unit 10 to the modem unit 4 is modulated, the passband is determined by the carry frequency mark 1270HZ and the space 1070HZ by the bandpass filter 100, and then the Data is transmitted to the transmission line through the DAA unit 7 through the 2-To-4 hybrid.

In the case of 1200 BPS at the caller's reception, the data signal of mark 2400HZ input from the DAA unit 7 through the 2-To-4 hybrid of the demodulator and the hybrid 130 is applied to the band pass filter by the control selection signal of the CPU 30. At 100, the demodem and the demodem of hybrid 130 are input. A predetermined frequency generated by the counter circuit 60 is supplied to the demodem and the hybrid 130 by the demultiplexer 160 and the multiplexer 170 control selection signals as described above in the CPU 30.

Therefore, the demodulators of the demodulators and the hybrid 130 are demodulated, input to the CPU 30 as digital signals, descrambled, and then latched 150 by the control signals of the CPU 30 to transmit and receive. It is received by the terminal in series through the receiving line of the input unit 10. The modem unit 4 is controlled by demultiplexing the data of the line 32 by the demultiplexer 160 by the control signal output through the line 33 of the CPU 30 when receiving 300BPS at the call side. Thereafter, the received data passes through the DAA unit 7 and the FSK modulation signal of the carrier frequency mark 2225HZ and the spacer 2025HZ, which is input to the modem unit 4 via the 2-To-4 hybrid of the demodulator and the hybrid 130, is transferred to the CPU 30. The modem unit 4 is demodulated to a serial digital signal by the modem unit 4 enabled by the control signal of the control unit, and is then serially input to the terminal via the transmit / receive input unit 10. In the answer mode, when 1200 BPS is transmitted, a signal modulated by the PSK of the call carrier frequency 2400 HZ is transmitted when data is transmitted. Thus, the band pass filter 100 becomes a passband of 2400 HZ by the CPU 30 control signal. The PSK modulation data output from the / A converter 80 is filtered into an analog waveform and transmitted to the telephone line via the DAA unit 7 through the 2-To-4 hybrid of the demodulator and the hybrid 130.

In case of 300BPS when transmitting in response mode, serial digital data inputted to the transmit / receive input unit 10 enables the transmitting end of the modem unit 4 by the control signal of the CPU 30, thereby causing the FSK to be transmitted from the modem unit 4. In order to be converted into an analog signal. This signal becomes the response tone frequency 2225HZ and is transmitted through the DAA unit 7 through the hybrid of the demodulator and the hybrid 130 through the band pass filter 100. In the response mode, when receiving 1200 BPS, the analog data signal modulated by the PSK of the response carrier frequency 1200HZ through the DAA unit 7 and the hybrid modem 130 is input to the band pass filter 100. In response mode, the control signal of the CPU 30 determines the band pass filter 100 as a pass band of 1200HZ, and outputs the band data by filtering the band data by the band 30 filter. As described above, the selection control signal according to the transmission and reception of data of each part is generated in the demultiplexer 160 and the multiplexer 170, and the output signal of the bandpass filter 100 is received by the demodem and the hybrid 130, and the demodem After demodulating the serial digital signal, it is descrambled by the CPU 30 and outputted to the terminal through the latch 150 and the transmit / receive input unit 10.

In response to 300BPS in response mode reception, when the input FSK analog signal (mark 1270HZ, space 1070HZ) enables the enable end of the modem unit 4 by the control signal of the CPU 30, the input signal is received and serial digital. After demodulating the signal, it is input to the terminal through the transmit / receive input unit 10 through the latch 150.

Here, when the 300BPS, the display unit 20 turns off the other display device (LED) to determine the speed, and when the 1200BPS is turned on, it is easy to distinguish the user according to the combined use.

As described above, since the automatic dialing and answering function are processed quickly, the modem has the advantage of being able to provide a high-performance modem because the convenience of the modem and the error occurrence rate due to misoperation are reduced.

Claims (4)

Input / output unit 1, which transmits / receives data from the terminal by RS-232C connection and displays distinctive indications for each operation, and 300BPS according to the designated transmission rate from the input / output unit 1 The automatic bow of / 1200BPS is determined, and the central control unit (2) which scrambles / descrambles the data according to 300BPS / 1200BPS by the control signal, and the modem and the telephone line of the other party are connected so that the relay is driven when the pulse or tone dial is dialed. In the modem having the DAA unit 7 is detected and the data is transmitted and received, the scrambled sampling signal from the central control unit 2 is converted into an analog signal and modulated by the control signal of the central control unit 2. The bandpass frequency is determined according to the transmission rate, and the conversion filter unit 3 having a function of amplifying the transmission filtered signal and information inputted from the input / output unit 1 are converted into the FSK modulation scheme. Modem 4 capable of demodulating and transmitting / receiving at 300BPS transmission rate and receiving a clock signal from a clock generator of the central controller 2 generates a predetermined frequency to control according to transmission and reception of 1200BPS. The control counter 5, receiving filter function, speaker drive and demodulation function according to the carrier frequency output from the control counter 5 and the control signal output to the central control unit 2 to the conversion filter unit 3 A modem comprising a hybrid and demodulator unit 6 which receives and receives data input and output from and receives, filters, demodulates and transmits the signals, and processes the operation according to each function and automatically adjusts gain. In auto answer / auto dial circuit. The demultiplexer / multiplexer (160, 170) is connected through lines (33, 34) so that the control counter (5) receives a selection control signal generated from the central control unit (2). An output line 38 of 160 is connected to the modem integrated circuit 4, a receive data line 39 of the demodulator and hybrid 6 is connected to an input of a multiplexer 170, and the multiplexer 170 Is connected to the central control unit 2, an output line 37 of the demultiplexer 160 is connected to control the count mode of the counter circuit 60, and the count circuit 60 The answering machine of the modem 834, 36 is configured to be connected to the central control unit (2) and the demodulator and hybrid unit (6). In a method for automatic dialing of a modem having a terminal, a central control unit (2), and a DAA unit (7), the terminal receives an AT comment to determine a data transmission speed and format, and inputs data corresponding to an electronic / mechanical dial mode. In the first step of checking the check in the central control unit 2, and when the electronic / mechanical method is checked in the first step to turn on the relay of the DAA unit 7 to drive the speaker and the pulse / In the second process of dialing according to the dial mode according to the tone dial mode and outputting the standby carrier, wait for a predetermined time when there is no standby carrier, and then turn off the relay of the DAA unit 7 and check whether 1200BPS is available when the standby carrier is present. In the third process, and when the 1200BPS in the third process, the scrambled data is transmitted and the connection status is displayed, and when the 1200BPS is not 1200BPS, the low channel of the call is used. Automatic dialing method according to the modem, characterized by constituted by any fourth step of displaying the connection state and to send a large online. In the automatic answering method of a modem having a terminal, a central control unit (2), and a DAA unit (7), the central control unit (7) determines a data transmission speed and a format by a command input through the terminal. In the first step of checking and the automatic response in the first step, the status according to the automatic response is displayed, the count register value according to the ring signal input is decreased in accordance with the call signal input, and the "A" digit is not. A second step of checking an input and sending a response theory carrier; a third step of receiving a carrier sent in the second step and checking whether the 1200BPS transmission mode is received when it corresponds to 1200BPS; and in the third step, 1200BPS transmission mode If not, the fourth step of connecting the line by checking whether the call mark tone frequency (1270HZ) in the central control unit 2, and the scrambling of 1200BPS in the 1200BPS transmission mode in the third step The fifth step is to check the mark, wait for a predetermined time when there is no mark, and display it without a carry when there is no mark, and send a call carrier frequency (2400HZ) for 1200BPS and display the connection state when there is a scramble mark of 1200BPS. Auto dial method in the modem characterized in that consisting of.

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