KR920003375B1 - Picture image information communication control device and method - Google Patents

Abstract

The apparatus includes a system bus (7) for carrying out transmissions and controls between modules. A system control means (5) performs control functions and interrupt control functions for the system, and DTMF and modem signal processing means (2,3) perform modulating and demodulating functions, while a general switching line connecting means (1) connects a telephone to a general switching line. A ROM (4) is connected to the system bus, and stores a program for controlling the communications of the DTMF and modem signal processing means (2,3), while a RAM (6) is connected to the system bus (7), and stores temporary data.

Description

Image information communication control apparatus and method for general switched line

1 is a block diagram of the present invention.

2 is a block diagram of an image control sound used in the present invention.

3 is a control procedure diagram of the applied device of the present invention.

4 is a transmission control procedure diagram of FIG.

5 is a control diagram of a receiving side in FIG.

* Explanation of symbols for main parts of the drawings

1: general switched line connection 2: modem

3: DTMF Receiver 4: ROM

5: system control unit 6: RAM

7: bus

The present invention relates to an apparatus and method for controlling image information communication in a communication system of image information capable of transmitting and receiving still image information intended by a user during a voice call within an appropriate time using a general switched line (general telephone switching network). will be.

The video telephone according to the recent TTC standard (Japanese TTC JJ-40.10, “Still image communication method in analog telephone band”, 1988.5.31) is a dual tone signal of I633Hz and 2006Hz as a transition signal from a voice call state to a video communication state. For image information, about 1747 pixels per second are transmitted by combining a change in amplitude and phase with a carrier frequency of about 1747 Hz.

However, in the above communication control method, first, the system is prone to malfunction due to the dual tone included in the whistle component of the voice during the voice call. Second, since the image information is transmitted according to the change in amplitude and phase, which is analog method, 64 per pixel. It has a disadvantage that it is difficult to distinguish more than gray level.

Accordingly, an object of the present invention is to change the state of video communication in the voice call, the speed of transmission, the type of information to be transmitted using DTMF signals, and to modulate the CCITT Recommendations V.29 and V. A device capable of transmitting images with 256 gray levels faster than the speed by the communication method by using the 9600, 4800, 2400bps modulation and demodulation method specified in 27 ter and controlling them properly. And to a method.

The present invention provides a system bus having a control and information transfer function between each module, a system control means connected to the bus means for system control and interrupt control, and 9600bps, 4800bps and 2400bps connected to the bus. Modem and DTMF signal processing means having a demodulation function according to a communication speed of a communication speed, and having DTMF signal transmission / reception means, general switched circuit connection means for connecting the modem and DTMF signal processing means and a telephone to a general switched line, and the system bus And a program ROM incorporating a program for controlling communication between the modem and the DTMF signal processing means, and a RAM for storing temporary data connected to the system bus.

In addition, the image information communication control method of the present invention transmits the image control information at a communication speed of 9600 bps and transmits a series of binary " 0 " signals, and a second step of calculating a bit in which an error occurs after the first step. After the second step and after the second step, if the error rate reaches a certain rate, the DTMA signal is used to adjust the speed to reduce the communication speed to 2400 bps and transmit the image at a constant rate. It consists of a third step of performing transmission and reception of the.

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

1 is a schematic diagram of the present invention, where 1 is a general switched line connection, 2 is a modem, 3 is a DTMF receiver, 4 is a ROM, 5 is a system controller, 6 is a RAM, and 7 a system bus. Represent each.

The present invention is composed of a system control unit 5 having a bus structure, a ROM 4, a RAM 6, a modem 2, a DTMF receiver 3, and a general switched line connection unit 1 as shown in the figure.

The system controller 5 is composed of a CPU and a peripheral circuit (timer, DMA controller, etc.) and is connected to an address, data, control line, and interrupt signal line on a bus to perform a communication control method by a ROM program.

The ROM 4 program is assigned to the memory map of the CPU to control the operation of the entire system, and performs the control procedure by controlling the DTMF generation circuit built in the modem 2 during transmission.

The RAM 6 is used for storing information necessary for temporary storage of the CPU of the system controller 5 and is allocated to a memory map.

The modem 2 has a built-in modulation and demodulation function by the CCITT V.29 and V.27 ter and DTMF generating means, and is mapped to the memory or I / O of the CPU through the bus, and the internal register and the RTS (transmission request) This operation is performed by a hint shaking method by the control signal of the CPU. In addition, the demodulated signal is transmitted to and received from the general switched line through the access device.

When the DTMF receiver 3 receives a signal on the line through the general switched line connection unit 1 and a valid DTMF signal is detected, it is notified to the CPU by an interrupt method, and 4-bit data (D0-D3) are connected to the CPU by connecting to the CPU. Make it known.

The general switched circuit connection unit 1 is composed of a transformer T that satisfies the terminal resistance of the terminal and an appropriate signal amplification means. The circuit is initially connected to a telephone and a modem in a video communication state. The connection switch is controlled via the CPU's control lines and relays.

Amplifying means at the transmitting end is composed of a capacitor (C1), resistors (R1, R4, R11), and operational amplifier (A1), the amplifying means at the receiving end is a resistor (R7, R5, R2), condenser (C2), It consists of an operational amplifier A2.

In addition, the input stage of the amplifying means for inputting the DTMF receiver 3 has a high impedance and serves to adjust only the AC component to the input level of the receiver. Here, the amplifying means is composed of capacitors C3, C4, C5, resistors R3, R6, R8, R9, R10, and operational amplifier A3.

2 is a configuration diagram of the image control sound used in the present invention and FIG. 3 is a control procedure diagram of the applied device of the present invention. The ROM 4 program performs the control procedure shown in FIG. 4 using the DTMF signal as shown in FIG.

That is, in the voice call state, the transmitting side transmits a video control sound consisting of three fields and switches to the call communication state. The first field is two DTMF signals, which start the video communication and the training information in FIG. If the quality of back network is poor, it indicates communication resume by speed reduction after NAK signal from receiving side, ACK or NAK signal of receiving side.

The second field is a speed field, which is a signal for notifying the receiving side of the transmission speed of image information at 9600 bps, 4800 bps, and 2400 bps. The third field indicates the type of information, and indicates the type of image information to be transmitted (black and white or color image), the size, the presence or absence of character information, and the type of character information in the case of character information.

However, the third field is not used when resuming the communication due to the speed reduction after training, and the second field and the third field are not used when the ACK or NAK signal is used. The DTMF signal has a transmission time of 100 msec and a no signal time of 50 msec.

In FIG. 4, the terminal receiving the image control sound has to transmit an ACK signal within 100 msec after reception. The transmitting side that receives the ACK signal continuously trains information having a continuous value of '0', and the receiving side receives a bit having an error. If it is more than appropriate, the NAK signal is sent. Otherwise, the ACK signal is sent.

The transmitting terminal receiving the ACK signal transmits the image information at the promised communication speed, and then switches to the voice call state. When receiving the NAK signal, the transmitting terminal defines the resumption of communication by decelerating the first field of the image control sound. Two DTMFs are used, and the second field is a DTMF signal representing a decelerated speed, and is sent after a 100 ms time delay to be retrained.

If it decreases in the order of 9600bps, 4800bps, 2400bps, but decelerates to 2400bps, it transfers the image information without training again and switches to the voice state.

FIG. 5 is a flowchart showing a transmission side control procedure in FIG. 4, and FIG. 6 is a flowchart showing a reception side control procedure in FIG.

First, referring to FIG. 5, the transmitter-side control procedure transmits the image control sound 12 at a speed 11 of 9600 bps after the voice call disconnection 10, and sets a timer for 400 msec (13). When the ACK signal is received within the timeout, the training signal is transmitted and the timer is set again for 400 msec. When the ACK signal is received within the timeout, image information is transmitted (14 to 19,23), and the NAK signal is not received without receiving the ACK signal. If received (19,20), the communication speed is reduced to 2400bps (21,22) to transmit the video information (23) and then connect the voice call (24).

Next, the receiving side control procedure will be described with reference to FIG.

If a video control sound of 9600bps is received after voice call disconnection (31) (31), it sends an ACK signal (32) and sets a timer (33), and if training is received within the timeout (34,35), until the last information. If the error is calculated and an error is 5% or more, a NAK signal is sent (36 to 39). If the error is within 5%, an ACK signal is sent and a timer is set (38, 40, 41).

If picture information is received within the timeout (42,43), the decoding and storage of the picture memory up to the last information (44, 45) are made (46) and the voice call is connected (46).

At this time, if the reception speed is decelerated from the transmitting side (47), if received at 2400bps speed proceeds in the order after the timer set 41, if not at 2400bps (48) proceeds to the timer set 49 step timeout If the image resumption sound is received (51), the processing proceeds to the ACK sending step 32 or less.

In addition, the present invention has a timer of 400msec at the end of the transmission of the image control sound and the completion of the training information transmission at the time of communication and stops the video communication state and switches to the voice communication state when the corresponding received signal is not received before the timer ends. The receiving end has a timer corresponding to 2 seconds, 8 seconds to 30 seconds when the ACK or NAK signal is transmitted for the image control sound and the response signal for the training information is completed, and when the information is not received, the receiver switches to the voice communication state. It was configured to.

The present invention is constructed as described above. First, by switching DTMF signals in a predetermined digit order, switching from the voice state to the video communication mode is assured, and the communication speed and the type of information of the image information can be transmitted within a short time. It is possible to transmit high-definition image information of 64 gradations or more, which is difficult to process by the existing method by transmitting image information by digital transmission method. Third, it is possible to adjust communication speed according to network quality by inspecting network quality by training. Fourth, the modulation and demodulation method used in the present invention is embedded in a single-chip device widely used in general-purpose facsimile, so that the system can be easily configured. (Up to 14400bps), it is expected to reduce the communication speed in the future.

Claims (9)

A system for transmitting or receiving still image information during a voice call using a general switched line, encoding or decoding the received image information or image information for transmission, and inputting or outputting image information using a video input / output device, A system bus (7) having a control and transmission function between each module, a system control means (5) connected to the bus means for system control and interrupt control, and a 9600bps, 4800bps and 2400bps of A modem and DTMF signal processing means (2,3), a modem having a demodulation function according to a communication speed, and means for transmitting and receiving DTMF signals, and the modem and DTMF signal processing means (2,3) and a telephone for connecting to a general switched line. It is connected to the general switched line connection means (1) and the system bus (7) and contains a program for controlling the communication between the modem and the DTMF signal processing means (2, 3). And a program ROM (4) and a RAM (6) connected to the system bus (7) for storing temporary data. 2. The apparatus according to claim 1, wherein said modem and DTMF signal processing means (2,3) have a built-in DTMF generating circuit. 3. The program ROM (4) according to claim 2, wherein the program ROM (4) controls the DTMF generation circuit to generate a series of DTMF signals, and uses the signals to inform the start of video communication, the communication speed, and the type of information. And an acknowledgment message, and confirming the presence or absence of a terminal. 4. The apparatus of claim 3, wherein the DTMF signal has a transmission time of 100 ms and a non-signal time of 50 ms. 4. The apparatus according to claim 3, wherein the received DTMF signal is processed in an interrupt manner by said system control means (5). 4. The DTMF signal of claim 3, wherein the series of DTMF signals is used for resuming communication after decelerating the speed for initiating video communication and for mode switching in which the receiving end continuously transmits to the transmitting end. A DTMF signal indicates a communication speed, and the following two DTMF signals indicate a type of image information. 7. The image information communication control apparatus for a general switched line according to claim 6, wherein the last two of the five DTMF signals are capable of indicating transmission information of character information, thereby enabling text communication. A system bus (7), a system control means (5) connected to the bus (7), a modem and DTMF signal processing means (2,3) connected to the bus, the modem and DTMF signal processing means (2,3) and a telephone In a general switched line connection means (1) for connecting a public switched line to a public switched line, a program ROM (4) connected to the bus, and a RAM (6) connected to the bus, the communication apparatus for image information communication for a general switched line includes: A first step of transmitting image control information at a speed of 9600 bps and transmitting a series of binary " 0 " signals, a second step of calculating a bit in which an error occurs after the first step, and an error rate after the first step is constant After reaching the rate, adjust the speed with the receiver using DTMF signal to reduce the communication speed to 2400 bsp and transmit. If the error rate does not reach a certain rate, the third step is to send and receive image information normally. Image information communication control method for a general switched lines, characterized in that configured. The image control information of the first step includes image control sounds, wherein the image control sounds are composed of a series of DTMF signals, and the first two DTMF signals of the DTMF signals are used for initiating video communication. It is used for resuming communication after deceleration and for mode switching in which the receiving end continuously transmits to the transmitting end. The next one DTMF signal indicates the communication speed, and the next two DTMF signals indicate the type of image information. Image information communication control method for a general switched line.

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