JPH0720154B2 - Two-way communication system - Google Patents

Description

The present invention relates to a two-way communication system suitable for use in communication between a facsimile machine and a personal computer.

"Conventional technology" When performing data communication by personal computer communication, RS
It is common to use a −232C communication interface.

When performing data communication by this RS-232C, generally, it is considered to be effective means for communication to activate communication software and use it. In order to communicate by RS-232C, it is necessary to set the hardware in advance, and although these operations can be set on the communication software, the user needs special knowledge to operate this communication software. .

On the other hand, the printout function is essential for PCs and general PC application software.
It is one of the functions well known to the user. Therefore, by using this printout function, data transmission from a personal computer can be performed by a simple operation.

Therefore, as shown in FIG. 9, when the data communication is performed between the host side device, for example, the personal computer 20, and the slave side device (for example, the modem) 10X, the printout function of the personal computer 20 is used and RS- By using the 232C communication interface, the burden on the user can be reduced, and for the purpose of transmission, the purpose can be realized without starting communication software again, so an extremely effective means for communication. Can be said.

It is conceivable to use a printer interface instead of RS-232C as the communication interface.

However, since the printer interface is generally a one-way transmission interface from the personal computer 20 to the printer, this cannot be applied to data communication that requires two-way transmission.

Therefore, as shown in FIG. 10, there is an idea to avoid this by using an RS-232C interface for reverse transmission to the personal computer 20. That is, this is a case where a plurality of interfaces (printer interface, RS-232C communication interface) are used to perform bidirectional communication.

[Problems to be Solved by the Invention] In the case of performing data communication as described above, in the case of constructing a two-way communication system using a plurality of interfaces, in consideration of transmission from the personal computer 20, various problems as described above are considered. However, on the other hand, it is necessary to prepare a plurality of interfaces for bidirectional communication, which causes various problems in terms of cost and operation.

The problem is only the printer interface,
A bidirectional communication system may be constructed.

However, there is currently no idea to construct a two-way communication system with such a printer interface. .

Therefore, in the present invention, the bidirectional communication system can be constructed only by the well-known printer interface.

[Means for Solving the Problems] In order to solve the above problems, according to the present invention, in a printer interface including a busy line, a data strobe line, and a parallel data line, a slave side device is passed from a host side device through a data line. A clock is sent to the slave side device, and the slave side device transmits data synchronized with this clock to the host side device through the busy line, and the host side receives data in synchronization with this clock. It is a feature.

[Operation] When data is transmitted from the host side device, that is, the personal computer 20, to the slave side device, that is, the modem, it may be transmitted using a printer interface as usual.

On the other hand, when the personal computer side receives the data from the modem side, it becomes as follows.

The serial clock SCK is sent from the personal computer side to the modem side through the data line.

On the modem side, the received data is sent via the busy line BUSY to the microcomputer 20 in synchronization with this serial clock SCK.
Serially transmitted to.

By doing so, the busy line provided in the printer interface can be used as the data line.

The timing control is executed between the personal computer 20 and the modem side by using the busy line and the data strobe line until the data is transmitted.

[Examples] Next, with reference to FIG. 1 and subsequent figures, a case where the two-way communication system according to the present invention is applied to a data communication system between a personal computer and a facsimile machine as described above is described in detail. Explained.

In the present invention, bidirectional communication is realized by utilizing a printer interface 70 as shown in FIG.

FIG. 2 shows an example of the receiving system 1A in this two-way communication system, and FIG. 3 shows an example of the transmitting system 1B.

In the receiving system 1A shown in FIG. 2, reference numeral 10 is a facsimile adapter, and 20 is a host side personal computer. Reference numeral 30 is a printer for printing out data from the personal computer 20 and the like. The facsimile adapter 10 functions as a slave side device.

The data supplied from the telephone line is the network control circuit (NCU) 4
After passing through 0 and being supplied to the modem 50 for data demodulation, the demodulated data is converted by the parallel-serial conversion circuit 60 into 1-byte parallel data into serial data.

In order to convert the demodulated data to serial, in this example, in synchronization with the serial clock SCK supplied from the personal computer 20,
Converted to serial.

The serial-converted data is supplied to the personal computer 20 via the printer interface 70.

The printer interface 70 sends serial data.
The busy line provided in is used.

FIG. 3 shows an example of the transmission system 1B in the two-way communication system. The transmission system 1B is also a personal computer 20 and a printer 30.
In addition to the above, the facsimile adapter 10 is configured.

The data transmitted from the personal computer 20 is supplied to the printer 30 via the printer interface 70 and the necessary print processing is executed. In the case of data transmission, the data is supplied to the signal conversion means 100 via the printer interface 70, and the signal-converted data is transmitted via the modem 50 to the NCU 40.
Is supplied to the communication line side such as a telephone line. At this time, the personal computer 20 side is in the printout mode.

FIG. 4 shows an example of the printer interface 70.

From the personal computer 20 side, in addition to the 8-bit data lines D0 to D7,
A total of nine lines, that is, a strobe line (STB) and a busy line (BUSY), are led out, and these are led to the input terminal 71. In the input terminal 71, the data lines D0 to D7 are the terminals 72 on the printer 30 side.
Of the corresponding data lines D0 to D7. The data lines D0 to D7 of the printer-side terminal 72 are supplied to the modem 50 via the data bus. Also, one of the data lines of the terminal 72, that is, D0, is used to supply a reception block from the personal computer side during data communication.

First switching means 75 is provided between each strobe line STB of terminals 71 and 72 and busy line BUSY. When printing the data from the personal computer 20 as it is, the strobe line STB and the busy line BUSY at the terminal 71 are
Connected to the corresponding line of terminal 72.

When data communication, that is, received data is transmitted to the personal computer 20 side, it can be switched to the printer interface 70 side.

This switching is performed by a switching control signal (FAX) sent from the microcomputer 80. When the control signal FAX is obtained, the transistor 76 is turned on and the relay 77 is energized. As a result, the first switching means 75 is switched to the state shown by the solid line. As a result, the busy line BUSY is used as a data line for serial data.

The strobe line STB is used for timing adjustment during preprocessing for transmitting / receiving data.

That is, the strobe signal (STB for convenience, FIG. 6C) obtained from the personal computer 20 side is supplied to the set terminal of the D-type flip-flop 86 via the first switching means 75 and the amplifier 85. . When the strobe signal STB arrives, a high level pulse synchronized with the falling edge of the strobe signal STB is obtained from the Q terminal. This high-level pulse (hereinafter referred to as BUSY pulse) is
And is supplied to the D0 terminal of the second switching means 82.

The second switching means 82 is a switching means for using the busy line BUSY also as the data line DATA, and until the reception data is transmitted, the personal computer 20 and the printer interface 70.
Used as a signal line for timing adjustment with the side.

Therefore, until the data transmission is started, the busy signal of the Q terminal is sent to the busy line BUSY via the inverter 83.

Further, the BUSY / READY switching signal (FIG. 6E) output from the microcomputer 80 is sent to the second switching means 82 via the amplifier 88.
Supplied to the D0 pin. Therefore, the D0 terminal always maintains the low level from the time when the strobe signal STB is obtained until the time when the switching signal indicating the ready state is obtained.

The second switching means 82 is controlled by the switching signal SEND output from the microcomputer 80.

Now, the input reception data supplied to the terminal 73 is supplied to the parallel-serial conversion circuit 60, and the data is serial-converted (FIG. 6, A, D). As the clock for serial conversion, the serial clock SCK sent from the personal computer 20 is used (Fig. 6A). This serial clock is sent out using one of the data lines D0 to D7. In this example, the D0 data line is the serial clock SCK.
Also used as a clock line.

In synchronization with the serial clock SCK, the serially converted 1-byte input received data is transferred to the busy line BUSY via the inverter 79, the D1 terminal of the second switching means 82, the inverter 83 and the first switching means 75. Sent out. with this,
The received data is serially transmitted to the personal computer 20 side.

The strobe signal STB obtained from the inverting terminal of the D-type flip-flop 86 is supplied to the microcomputer 80, and the arrival of the strobe pulse STB is detected.

FIG. 5 shows a personal computer 20 and a modem 50 when receiving data.
3 is an example of a control program for exchanging signals with and.

Therefore, it is assumed that the first switching means 75 is switched to the solid line side and the second switching means 82 is switched to the D0 terminal side.

First, when the control program 120 on the personal computer side is started, the confirmation processing is performed by the control program 140 on the facsimile adapter 10 side with the sending of the status clocks ST and CK (steps 121 and 141).

The adapter side then checks whether there is an incoming call, and when there is an incoming call, a ready signal READY is sent to the personal computer side, and upon receipt of this ready signal READY, a strobe signal STB is sent from the personal computer side. This strobe signal STB is confirmed on the adapter side (1
22,123,143,144).

When the confirmation of the strobe signal STB is completed, a ready signal READY is sent from the adapter side and 1 byte of the received data is loaded. When the loading of the reception data is completed, the busy signal BUSY is transmitted (steps 145 to 147).

On the personal computer side, if this is confirmed by receiving the ready signal READY, then the BUSY signal is confirmed (steps 124 and 125). If both are confirmed, strobe signal STB is sent to the adapter side,
In response to this, on the adapter 140 side, the strobe signal S
TB confirmation processing is executed (steps 126 and 148). When the confirmation of the strobe signal is completed, the second switching means 82 is switched to the D1 terminal side so as to use the busy line BUSY as a data line (step 149).

When the switching of the busy line BUSY is completed, the serial clock SCK is sent from the personal computer side, and the parallel-to-serial converted received data is sent accordingly (step 12
7,150).

The personal computer sequentially receives the data bit by bit, and when the received data of 1 byte is input, the transmission of the serial clock SCK is stopped and the processing of the received input data is executed (steps 128 to 131). .

When the processing of the input reception data is completed, the strobe signal STB is transmitted in step 132, and therefore the adapter side confirms the arrival of the strobe signal STB and then switches the busy line BUSY to the original busy line ( Steps 151, 152). After that, it is checked whether or not the received data is completed up to the end of one page, and if it is not completed, the process returns to step 124, and the serial data is serially transferred byte by byte to the personal computer while checking the mutual timing by the same procedure as described above. It is transmitted to the 20 side.

When the input of data for one page and the transmission to the personal computer are completed, this control routine is exited (steps 133, 15).
3).

As described above, steps 121 to 123 and 141 to 144 are all steps for confirming reception preparation on the personal computer side, and steps 124 to 126 and steps 145 to 148 are steps for synchronizing the start of the received data. Is. These are all byte-synchronized.

Then, steps 127 to 129 and steps 149 and 150 are all bit synchronization sections. Then, the remaining steps 130 to 132 and steps 151 and 152 are both byte synchronization sections.

As a result, 1 byte of received data is serially converted in synchronization with the serial clock SCK sent from the personal computer 20 side, and 1 byte of data is transferred via the busy line BUSY in synchronization with this serial clock SCK. It is transferred serially (see A and D in Fig. 6).

FIG. 7 shows an example of the signal converting means 100 shown in FIG. The data for printout output from the personal computer 20 is taken in through the printer interface 70 described above and is temporarily stored in the RAM 101 for printer code buffer.

When the printer code buffer of the buffer RAM 101 is full, the busy signal BU is output from the printer interface 70.
SY is transferred to the PC 20 side, which causes the PC 20
The data transmission from is controlled.

Then, the data in the buffer of the buffer RAM 101 is sequentially
A character font of the character generator 103 composed of a ROM is read by the software interpreter 102, read out, converted into dot data, and expanded on the dot map memory RAM 104.

When the horizontal 1-line dot data is accumulated, the 1-line data is converted into facsimile data by referring to the code table of the code table ROM 106, and this is sequentially accumulated in the RAM 105 for the facsimile code buffer.

Then, the data is read from the facsimile code buffer RAM 105 at a timing corresponding to the communication speed, converted into a specified analog signal by the above-mentioned modem 50, and this is sent to the telephone line side through the NCU 40.

In the facsimile data, an EOL signal, which is a line delimiter signal, is inserted for each horizontal line, and the transmission time of the one line is specified. Delimiter signal EOL for 1 line data transmission within the specified maximum time
A signal of logic 0 is inserted between and. Further, 8-bit facsimile code data is generated and transferred to the modem 50 in 8-bit units.

As described above, in the signal converting means 100, the print-out data transmitted from the personal computer 20 is once expanded into dot information through the printer interface 70,
This is encoded and directly transmitted to the facsimile machine of the other party through the telephone line by the specified modem 50.

FIG. 8 is a flowchart showing an example of this signal conversion processing. When the data, that is, the data for printout, is received from the personal computer 20 by the interrupt processing, it is stored in the buffer RAM 101 and then processed according to the procedure of FIG. That is, the data for printout is sequentially read from the data buffer RAM 101, and it is checked whether the data is command data or raw data (that is,
111,112).

In the case of command data, the data is analyzed and various settings are made (step 113). Then, the process returns to step 111 again.

When the captured data is raw data, it is checked whether the data is code data or dot data (step 114). If it is code data, a character is recognized from the received character code,
The character font will be read (step 115).

The obtained font data is stored in the virtual VRAM and dot development is performed (step 116). The dot map memory RAM 104 is used for this.

After the dot development, when the development for one line is completed, one vertical line is viewed horizontally, and one line of data is sequentially stored in the facsimile code buffer RAM 105.

Thereafter, as described above, the data stored in the code buffer RAM 105 is sequentially read byte by byte by the interrupt processing of the modem as described above, converted into an analog signal, and transmitted to the telephone line side.

As described above, according to the present invention, in the printer interface, the host side device sends the serial clock to the slave side device through the data line, and the slave side device synchronizes with the serial clock. The received data is transmitted to the host side device through the busy line, and the host side receives the data in synchronization with this clock.

According to this, bidirectional communication of data becomes possible only by the printer interface.

In this case, the busy line and the data strobe line are skillfully used so that the received data is serially converted and bit-synchronized and sent to the host side device.

Therefore, at the time of transmission, the data for printout obtained from the host device is transmitted to the communication line via the modem as it is, and the received data received from the communication line is once serial-converted and then sent to the personal computer side. Will be supplied.

As a result, bidirectional communication is possible only with the printer interface shown in FIG. That is, it is not necessary to provide an RS-232C communication interface in addition to the printer interface as in the conventional case. As a result, the bidirectional communication system of this kind has a characteristic that it can be utilized extremely efficiently.

Therefore, the two-way communication system according to the present invention is very suitable for application as a facsimile adapter for data communication between a personal computer and a facsimile machine.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a bidirectional communication system according to the present invention, FIG. 2 is a system diagram showing an example of a receiving system in this bidirectional communication system, and FIG. 3 is an example of a transmitting system thereof. System diagram, FIG. 4 is a configuration diagram showing a specific example of the printer interface, FIG. 5 is a flow chart showing the relationship of signal transmission / reception at the time of reception between the software side device and the slave side device, and FIG. 6 is provided for explaining the operation thereof. Waveform diagram, FIG. 7 is a system diagram showing a concrete example of the signal converting means, FIG. 8 is a flow chart showing an example of a control program for explaining the operation thereof, and FIGS. 9 and 10 are both for explaining the present invention. It is a block diagram of a communication system for communication. 1A: Receiving system for bidirectional system 1B: Sending system for bidirectional system 10: Facsimile adapter 20: Personal computer (device on software side) 30: Printer 40: NCU 50: Modem 60: Parallel series Conversion circuit 70 ...... Printer interface 71, 72 ...... Terminal 74 ...... Buffer circuit 80 ...... Microcomputer 75, 82 ...... First and second switching means 100 ...... Signal conversion means D0 to D7 ...... Data line BUSY ...... Busy line (busy signal) STB …… Strobe line (strobe signal)

Claims (1)

[Claims] 1. In a printer interface composed of a busy line, a data strobe line and a parallel data line, a clock is sent from the host side device to the slave side device through the data line, and the slave side device synchronizes with this clock. A two-way communication system characterized in that data is transmitted to a device on the host side through the busy line, and the host side receives data in synchronization with this clock.