JPS63288556A - Method for communicating image - Google Patents

Abstract

PURPOSE:To widely simplify a transmission procedure and to execute the efficient communication by transmitting picture information with a high speed MODEM at high speed and transmitting/receiving the picture information after a transmission starting signal is transmitted for a constant time. CONSTITUTION:When a switch 3 is turned on by a transmission button operation, a transmission control program is executed, and a relay 1 is turned on and switched by the control of a CPU 2. Then, a MODEM 5 is connected to a line, the transmission speed of the MODEM 5 set by a switch 4 is discriminated and the MODEM 5 is transmitted and activated by the transmission speed. Further, the MODEM 5 transmits a DTMF signal corresponding to the transmission speed for a constant time a little longer than a time necessary for the signal discrimination at a receiving side by the control of the CPU 2 and thereafter, a silence status is obtained only for the time necessary to change the transmission speed. When the transmission speed of the MODEM 5 is switched at high speed, the CPU 2 does not execute the conventional pre-procedure processing, outputs successively picture information to the MODEM 5 and starts the high speed transmission of the picture information.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image communication method that utilizes a telephone network to transmit and receive image information using a high-speed modem.

[Conventional technology]

Conventionally, in image communication, such as facsimile communication, which uses a telephone network and a high-speed modem to send and receive image information,
Based on the so-called T-series recommendations, in order to perform the specified communication by operating the multi-page function, error playback function, polling function, 9 enclosure check function, etc., each pre-procedure and post-procedure process is performed before and after transmitting image information. It is necessary to do this.

In other words, in facsimile communication, the sequence of communication procedures is as described in pages 74 to 79 of [CCUTT Red Book Vol. consists of 57 steps of phases A, B, C (C1, C2), D, E, and F. Before and after phase C, which transmits image information, there are pre-procedures of phases A and B, and phases D and E. Each post-step is executed.

Note that each phase A and F is defined as follows.

Phase A (Call Setup): Executed manually or automatically, when the receiving device starts up, it converts the 2100 Hz tonal signal into the called station identification signal (
CED) from the sending device for approximately 3 seconds.

Phase B (Brief message hand jll): Function identification signals (DIS, NSF) and digital command signals (D
C8) is exchanged between devices on the receiving side, and the function to be used when transmitting image information (when transmitting a message) is selected.
Training of sending equipment.

Training check signal (TR), (TCP)
The state of the line is checked by a training sequence using the receiving readiness confirmation signal (CFR) of the receiving side device, and forwarding/packing is performed as necessary.

Phase C: Using the functions selected in Phase B, image information is sent and received according to the in-message procedure (phase c1) and the message transmission procedure (phase c2).

Phase D (Bost Message II [[): The transmitting device informs the receiving device whether or not the transmission is complete using the message end signal (EOM), multi-page signal (MP8), procedure end signal (EOP), etc. In addition to broadcasting, the message confirmation signal (MCF) of the receiving side device,
! J) Notify the sending device of the presence or absence of errors in the received information by means of learning affirmation and denial signals (RTN) and (RTP).

Phase E (call release): Executed manually or automatically based on the line disconnection command signal (DCN) of the sending device.

Also, only in Phases B and C, a high-speed modem is used.
s high-speed communication is performed, and the remaining phase A.

For D, E, and F, communication is performed at 300 bps.

In the case of manual transmission and reception, in which the transmitting and receiving devices are set for transmitting and receiving image communication respectively by operating the transmitting and receiving buttons, communication is performed according to the transmission sequence shown in Fig. 5, and at this time, the phase A, B, I),
The time required for E is approximately 3 seconds, 8 seconds, 2.5 seconds, and 1 second, regardless of the amount of image information.

Note that each symbol in FIG. 5 indicates each signal explained in the definition of phases A and F.

[Problem that the invention seeks to solve]

By the way, in conventional image communication, such as the aforementioned facsimile communication, which requires pre-procedure and post-procedure processing,
There is a problem that efficient communication cannot be performed when the amount of image information to be transmitted is small.

For example, in the case of the above-mentioned facsimile communication, regardless of the amount of image information, the pre-procedures of phases A and B and phase D,
It takes about 15 seconds for the E and post-procedures, so when transmitting image information with a small amount of information on the order of seconds, such as simple messages and figures, most of the total communication time is spent on the pre- and post-procedures. Efficient communication becomes impossible.

[Failure to solve the problem]

This invention was made with the above points in mind,
In an image communication method that uses a telephone network to send and receive image information using a high-speed modem, a device on the sending side transmits a specific D based on a transmission request operation.
After transmitting a transmission start signal such as a TMF signal for a certain period of time, the transmission of the image information using the high-speed modem is started, and only when the receiving side device receives the transmission start signal for a specified period of time or more. , an image communication method characterized in that reception of the image information using the high-speed modem is started.

[Effect]

Therefore, according to the present invention, after a transmission start signal consisting of a specific DTMF signal or the like is transmitted for a certain period of time,
The transmission and reception of image information using high-speed modems has begun, and the transmission procedure has been greatly simplified compared to, for example, conventional facsimile communication, especially for simple image communication where the amount of image information to be transmitted is small. By applying this method, efficient communication using a high-speed modem can be performed.

〔Example〕

Next, the present invention will be explained in detail with reference to the drawings of FIGS. 1 to 4 showing an embodiment thereof.

The transmitting and receiving side devices are each configured as shown in Figure 2. In the figure, (11 is a connection switching relay called a cml relay, which has on/off contacts (on), (
of) two changeover switches 115, clr
The switching pieces of both switches ni and +15' are connected to a pair of line terminals of the telephone network, and the off contacts (0'') of both switches ni and ni' are connected to a telephone set in the device, Based on the control of a microcomputer which will be described later, both switches n'r and ti7 are switched to on/off contacts (on) and (off) in conjunction with each other.

(21 is a microcomputer for communication control (hereinafter referred to as CP)
(referred to as U), which controls the switching of relay (1),
The device is controlled for each of normal telephone communication and image communication.

(31 is a transmission switch that is turned on and off by operating the transmission button, and outputs an on signal of logic 0 (Arne level/I/) to the CPU (2+) as a transmission command signal. (4)
is a modem speed changeover switch that changes the transmission speed of the high-speed modem, which will be described later.
Connect the logic 0 contact signal for 2400 bps command to contact f.
Alternative output from a) and (b) to the CPU (21).

The r51 is a high-speed modem connected to the CPU (2r), and has the function of transmitting and receiving image information, as well as the function of generating and transmitting a dual tone multi-frequency DTMF signal for a button telephone.
(By the control of 21, the transmission speed when transmitting and receiving image information is set to either 4800 bps or 2400 bps, and when transmitting image communication, a transmission start signal consisting of a specific DTMF signal and a signal of image information are set. The modulation signal is transferred to the transformer (6) and the switch pi, (1'X
When image communication is received, the switch +! , +15' contacts (ON) and the transformer (6), the image information signal is demodulated and output to the CPU (2+).

(7) has a transformer (8) and a DC cut capacitor (9) on the input side, and a switch (Tll) via (95).
, is a DTAfF receiver device for receiving DTMF signals connected to the contact point (Of) of nr, and is connected to the switch nr from the telephone network.
The CPU (
2) Output.

Note that a network control device port O called NCU is formed by relays i1), lances (6), f8), capacitors (9), and t9'r.

By the way, DTMF signals are 16 types of tone signals set corresponding to each button on a button telephone.
Currently, only 12 types of DTMF signals are actually used, and the remaining 4 types of DTMF signals are not used.

In this example, four types of l are not used.
) Two specific types of TMF signals (DTMF-A
, B), the transmission speed is 4800 bps, 2400
It is used as a transmission start signal for each bps, and communicates image information while eliminating malfunctions caused by DTMF signals from pushbutton telephones.

On the other hand, the relay (1) is normally switched off and held, and the switches (ti, ttr) are kept in contact (Of), causing the transmission.

A telephone call is made between the telephones of the receiving devices.

Image communication is performed after the telephone of the receiving device responds to a call from the telephone of the transmitting device, the telephones of both devices are taken off-hook, and the lines between the two devices are connected.

Note that the telephones of both devices are operated manually.

Next, the operation and operation of image communication will be explained.

By the way, the CPU (21 is the third
The image information transmission control program shown in the figure and the image information reception control program shown in FIG. 4 are stored in advance as subroutine programs. In addition, Y in Figures 3 and 4,
N is affirmative. Show each negative.

Then, when the switch (3) is turned on by the transmission request operation, that is, the transmission button operation, the transmission control program is executed, and under the control of the CPU (2+), the relay (1) is switched from off to on, and the switches ni, nf' is switched to the contact (On), the modem 151 is connected to the line, and the transmission speed of modem +51 set by the switch [4] is identified, and the modem (5) transmits at the identified transmission speed. will be activated.

Furthermore, under the control of the CPU (21), the modem (5) immediately sends a DTMF signal corresponding to the transmission speed, that is, a DTMF signal of DTMF-A or B, for a period slightly longer than the time required for the receiving device to identify the signal. a certain amount of time.

For example, transmit at 300 bps for 300 milliseconds, and then use uJff. For example 7
There will be no signal for 5 milliseconds.

Then, when the transmission speed of the modem R51 is switched to a high speed of 4800 bps or 2400 bps, the CPU
In addition to processing the front hand of conventional facsimile communication, f21 sends image information such as messages, graphics, or images of the sender's face, captured in advance by an image sensor or COD camera, to the modem (5). The images are output sequentially and high-speed transmission of image information is started.

Note that while image information is being transmitted, the transmission carrier signal output from the modem (5) is changed from a low speed carrier signal of aoo bps to a high speed carrier signal.

Moreover, the training signal (TR) is added to the beginning of the image information signal transmitted from the modem (5), as in the case of FIG. 5.

Furthermore, once the image information has been transmitted, the CPU (2
Under the control of switch 1, transmission of modem +51 is stopped and relay (1) is switched off and switch +1 is turned off.
1, (11 is switched to contact (Of), modem r
5) is disconnected from the line and returns to the state before sending.

On the other hand, when the send button is not operated, the CPU (21
The output signal of the receiver (7) is constantly monitored by
When a DTMF signal is received by the receiver (7) while the line is connected, the reception control program is executed and the C
PU (21) is a relay (1) that switches to receiving image information only when a DTMF-A or B signal is continuously received for a preset specified time for signal identification, for example, 250 milliseconds or more. ) and connect the modem r5), which is waiting for reception, to the line.

Note that the switching of the relay (11, etc.) on the receiving side device is performed while the modem ζ5 on the transmitting side device is in a no-signal state.

When the image information starts to be received, the modem (5) is switched to the transmission speed of the signal being received, and the image information signal demodulated by the modem (5) is output to the CPU (21).

Further, the CPU (21) detects the presence or absence of a high-speed carrier signal for conveying image information, and detects the presence or absence of a high-speed carrier signal for conveying image information.
The relay (1
) to disconnect the modem r5+ from the line, and automatically terminate reception of image information.

Therefore, the devices on the sending and receiving sides operate as shown in Figure 1 during image communication, and after the line between the devices is connected, pressing the send button on the sending device causes the device to become a relay. +11 is turned on, and after transmitting a specific DTMF signal corresponding to the transmission speed of modem R51 for a certain period of time, the transmission of image information using the modem (5) is started,
When the transmission of the image information is completed, the relay (1) is switched off to end the transmission.

In addition, by receiving a specific DTMF signal for more than a specified time, the receiving device turns on the relay 111, starts receiving image information using the modem R51, and connects the high-speed carrier for transporting the image information. When the image information is no longer detected and the reception of the image information is completed, the relay (1) is switched off to end the reception.

Therefore, in the case of the above embodiment, only about 0.4 seconds of the total communication time is used for communication other than image information, and in particular,
By applying the present invention to a simple image information transmission device with a small amount of image information, such as a simple television conference device or a telewriting device, efficient image communication can be performed using a high-speed modem.

After the image information has been transmitted, a normal telephone conversation using the telephones of the sending and receiving devices is performed, and a check is made to see if there are any transmission errors.For example, 4800B
If a transmission error occurs due to ps transmission, the image information can be retransmitted after switching the switch (4) of the transmitting device and changing the transmission speed of the modem 151 to 2400 bps.

By the way, in the above embodiment, the transmission speed of the modem c51 is set to one of two types to transmit image information at high speed.
The transmission speed of the modem C51 may be set to either one type or three or more types to transmit image information at high speed.

Furthermore, it goes without saying that the transmission start signal, the fixed time for transmitting the signal, and the prescribed time may be different from those in the embodiment.

〔Effect of the invention〕

As described above, according to the image communication method of the present invention, transmission,
After transmitting the transmission start signal for a certain period of time, the image information is transmitted at high speed using a high-speed modem, and the image information is sent and received, which greatly simplifies the transmission procedure compared to conventional facsimile communication. In particular, when the amount of image information is small, efficient communication can be performed.

[Brief explanation of the drawing]

1 to 4 show one embodiment of the image communication method of the present invention, FIG. 1 is an explanatory diagram of a transmission sequence, FIG. 2 is a block diagram of the device, and FIGS. 3 and 4 are explanations of operation. FIG. 5 is an explanatory diagram of the transmission sequence of conventional facsimile communication. +21...CPt1, +31...Transmission switch, 15)...High speed modem, (7)...I) TMF receiver, aCt...Network control device.

Claims (1)

[Claims] (1) In an image communication method that uses a telephone network to send and receive image information using a high-speed modem, a device on the sending side sends and receives a specific D based on a transmission request operation.
After transmitting a transmission start signal such as a TMF signal for a certain period of time, the transmission of the image information using the high-speed modem is started, and only when the receiving side device receives the transmission start signal for a specified period of time or more. , an image communication method comprising starting reception of the image information using the high-speed modem.