JPS585050A - Image transmission system - Google Patents

Abstract

PURPOSE:To perform discrimination at a high speed by a simple circuit in an image transmission system which transmits plural kinds of information to the 1st transmission line and a clock signals synchronizing the information to the 2nd transmission line, by adding a discrimination signal to the information, and discriminating the kind of the information. CONSTITUTION:Image processors A, B, C, and D are looped by two optical fibers 1 and 2. Through the optical fiber 1, an image packet of image information and a command packet of control information are transmitted, and through the optical fiber 2, a clock signal synchronizing with the packets transmitted through the optical fiber 1 is transmitted. To discriminate between the image packet and the command packet, a discrimination signal is added to the head of each packet. Each image processor discriminates the image packet by the discrimination signal 1 and the command packet by the signal 0, and performs prescribed processing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a iii* transmission system, and more particularly to an image transmission system using 5-light transmission, in which MS information is transmitted using an optical fiber-shaped signal transmission member as a medium.

In recent years, optical fibers have been put into practical use as optical transmission members, and instead of transmitting information as electrical signals, attempts have been made to transmit information converted into optical signals using optical fibers as a medium. Such a transmission method using an optical fiber has advantages such as the optical fiber is lighter in weight than the signal to be transmitted and can be easily installed.

By the way, information can be broadly divided into 211 categories. One is data information that can only be recognized by computer means, and the other is great information that can only be recognized by humans through their eyesight. Conventionally proposed transmission methods using optical fibers handle data information, and these methods connect multiple devices using optical fibers and transmit data information from multiple devices by time-sharing means. It was something. However, the disadvantage of time division means is that there is a limit to the amount of information that can be transmitted per unit time, and the advantages of optical fiber, which is a medium capable of high-speed transmission, cannot be fully utilized. In addition, in order to clearly transmit images, the amount of image information for one original horizontal image becomes extremely large, and the nature of image information is that it is continuous [
It is preferable that it be transmitted. In this respect as well, if time division means is used, the optical fiber will be used exclusively for a long time while transmitting a large amount of information.

In view of the above points, the present invention provides high-speed discrimination between a plurality of pieces of information, such as IliigI information, and control information related to the transmission of image information, which are mixed in a signal transmission path using an optical fiber, in order to achieve high-speed transmission of #i-information. The purpose is to perform this with a simple circuit configuration.

Below, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a diagram showing connections in an embodiment of a loop transmission system using optical fibers to which the present invention is applied. A schematic explanation will be given using FIG. Hereinafter, the packetized image information will be referred to as an image packet, and the kerated control information will be referred to as a command packet. A, B, C and D
is a terminal device, for example, a document image reading unit equipped with a solid-state image sensor such as a COD, an image recording unit such as a laser beam printer, an optical-to-electrical converter (hereinafter referred to as an 0/E converter), and an electric-to-optical converter. This is an image processing device having a converter (hereinafter referred to as an E10 converter). As shown in the diagram, terminals A, B,
C! and D are connected in a loop by two parallel optical fibers. 1 is a packet line through which command packets and image data are transmitted, and 2 is a transmission line with a clock synchronized with the packets of packet line 1. That is, in the system of this embodiment, command information,
) Image buckets are transmitted over a common optical fiber, and high-speed transmission can be achieved by packetizing information and transmitting it.

When the system is started, that is, when power is turned on to each terminal, a command packet (hereinafter referred to as an empty packet) having no loop information is transferred. Further, a clock synchronized with this empty packet is transferred on the clock line 2. When the selection system is started, one terminal that can issue this empty packet is set in advance as a master terminal. In the system, one empty packet issued from one master terminal is sequentially transferred to the terminals, and the terminals mainly transmit the empty packet in a loop.

Then, each terminal can issue a command packet only when the terminal inputs one packet that is being transferred through the loop. This prevents command information from being output from multiple terminals simultaneously on the loop.

Furthermore, the terminals that can issue command packets when the system is started can be arbitrarily set. It should be noted that each terminal determines the input of a packet based on the input of the chronograph transmitted by the chronograph line 2. On the other hand, image packets are transmitted after mutual understanding between the sender and the receiver is established using command packets, so only the command information () is transferred over the loop when the device is started.

In the system shown in FIG. 1, terminal A is assumed to be a master terminal that can issue command packets when the system is started. now,
When terminals A, B, C, and D are powered on, terminal A first
A command packet is issued from the terminal DK and transmitted to the terminal DK.

This command packet is normally an empty packet, and the signal on packet line 1 is "0", but as the clock synchronized with the command packet is input to multiple terminals from clock line 2, the command packet is input. Recognized. The terminal analyzes the input command packet, and if it is found to be an empty packet, it then checks to see if there is a transmission request from the user, and if there is not, it only uses the clock. Transmit an empty packet to terminal C. However, if there is a transmission request to a terminal, the input empty packet will contain a bit indicating that a loop connection is in progress, the address of the terminal to which the image should be sent, the address of the terminal that sent the image (in this case, the terminal's address), and the image. Bits corresponding to the number of transmissions and image size information are set and transmitted to terminal C, after which a response to the command from the destination is awaited. The command packet, which was an empty packet at this point, has become a command packet containing the above-mentioned control information. Terminal C similarly analyzes and issues command packets, and further transmits the command packets to terminal B. Terminal B performs a similar operation and the command packet is transferred in one direction on the loop, such as to the terminal user and terminal A to the terminal.

As is clear from the above, the terminal that can issue command packets at system startup is the only one that is set as the master, and after that, each terminal can only issue command packets when it receives command packets. As mentioned above, no collision of information occurs on the loop.

Each terminal A, B, 0, and D is equipped with a timer.
This timer constantly detects loop breakage. This will be explained below.

Loop breakage refers to situations such as when one of the terminals is not powered on or when the optical fiber itself is cut. In the case of a loop transmission system, it is clear that all connected terminals and all teno optical fibers must be in perfect condition for the system to function. Furthermore, if the system is normal, the packet will definitely go around the loop once within a certain time after the packet is issued, and will be input again. This fact is utilized to detect loop breakage. When the power is turned on, terminal A, which is the only master capable of issuing command packets at the time of system startup, immediately issues command packets and starts counting the built-in timer. Thereafter, if a command packet is not input within a preset tie→operation period, it is determined that the loop has been broken. The other terminals B, O, and D start counting their timers after power-on, and then output a command packet for the first time if no command packet is input within the timer operation period set for each terminal. After that, if the next command packet is not input within a certain period of time, it is determined that the loop has been broken. In addition, in the case of a loose disconnection due to some reason during system operation after the system startup, all terminals start a timer at the same time as the packet is output, and check if the next packet is input within a certain amount of time. Always detects whether

This eliminates the need for a dedicated protocol for detecting loop breakage, and also eliminates the need for a dedicated circuit for that purpose. Similarly, as described above, the terminals that can issue command packets at the time of system startup can be set arbitrarily, and the setting time of the timer for loop disconnection detection is determined for each terminal according to this setting. According to the present invention, by packetizing and transmitting information in a loop transmission system, not only high-speed transmission is possible, but also information collision avoidance on the loop, loop disconnection detection, etc. can be easily achieved. FIG. 2 shows image reading units (readers) provided at terminals A, B, O, and D. The main reading section sub-scans A4 size originals in the horizontal direction and A3 size originals in the vertical direction, and the line density of reading 9 is 16 lines / m
In addition, it has a resolution of 16 pixels in the main scanning direction. Therefore, the number of bits in one main scanning line is 16 bits (y)/m
ix 2971m = 4752 focal points, and the sub-scanning is 16 lines cold in A4 size - X2101ig = 3360 lines, which is twice as large as 6720 lines in A3 size. As shown in FIG. 2, the reflected light from the original O irradiated by the fluorescent lamp I is imaged on two photoelectric converters 0CDI and 00D2 arranged in the main scanning direction through lenses L1 and L2, and the original 0 The image is divided into two parts, read, converted into electrical signals, and further formed by an adder P as one line of image information. In this way, image information of 3360 lines (A4 size) or 6720 lines (A3 size) is read.

As mentioned above, the image information is electro-optically converted and transmitted as image packets through optical fibers. Figure 3 shows an image packet. As shown in the figure, the image packet is synchronized with the clock transmitted by the clock line 2, and the data changes at the rising edge of the clock, and the clock falls at a stable point in the middle of the data.

An identification signal S is added to the head of the image packet, and a dummy clock DOL is formed on the clock line 2. The identification signal S is a control signal for distinguishing between an image packet and a command packet transmitted to the packet line, and is a "1" signal if the packet is an image packet, and a "0" signal if the packet is a command packet.

Based on this identification signal inputted to the terminal prior to the packet, each terminal determines whether the following information is an image packet or a command packet, and performs predetermined processing.

FIG. 4 shows a command packet. As described above, a dummy clock DOL is added to the clock line 2 at the beginning of the command packet, and an identification signal S of a "0" signal is added to the packet line 1. Also, like the image packet, it is synchronized with the clock signal transmitted by the clock line 2, and the data changes at the rising edge of the clock. The command packet has a 32-bit structure as shown in the figure.

FIG. 5 shows the details of the 32 bits of the command packet.

The 1st to 4th focuses are the setting of the first destination address, the 5th
~ The 8th pit is the setting of the number of transmissions to the first destination, the 9th pit is
The 12th bit is the setting of the second destination address, and the 13th to
The 16th bit is the setting for the number of transmissions to the second destination, and the 17th bit is
The 20th bit is used to set the source address. The 21st bit is the setting for the size of the image information to be transmitted. The signal "1" indicates A3 size 1 "The rust signal is A4 size. - The 22nd bit indicates that the sender indicates to the destination that it is ready to receive the image information. If the bit in question is a “1” signal, it will work.

The 23rd bit is a bit that signals the start of transmission of image information and functions with the rlJ signal. The 24th bit, g, is a bit in which the sender asks the destination to complete reception of the image information, and functions with a "1" signal. The 25th to 29th pits are blank. 30th
The bit is a response bit from the first destination in response to a command from the receiving source, and when rlJ, it indicates acknowledgment of the command.

The 31st bit is the response bit from the second destination and is “1”.
” indicates acceptance of the command.

The 32nd bit is a bit indicating that a transmission request has been issued from one of the terminals in the system and that the terminal is connected to the loop, and when it is "1", it indicates that the terminal is connected.

In this way, one command packet has the function of specifying multiple destinations, the function of transmitting responses from them, the function of specifying the number of transmissions to multiple destinations and the image size, and the function of preparing for reception from the source to the destination. Complete, start sending,
It has a function of inquiring or instructing completion of reception.

FIG. 6 shows a protocol procedure related to image 1 transmission when different numbers of image information are transmitted from terminal A to terminals B, O, and D for each sheep as an example of using the system of FIG. 1. Similarly, the addresses of each terminal are 1000 for terminal A, 0100 for terminal B, and 1100 for terminal C. Terminal Riwa 001
0 is the default. To describe a specific usage example, image information is transmitted from terminal A to terminal B, 1 image to terminal C, 2 images to terminal C, and 3 images to terminal R in A4 size.

Terminal A, which received the empty packet in (1), sets "1" in the loop connection of the command packet, and
Set the address of terminal B to "0100" as the destination, set the address of terminal C as "1100" as the second destination, and set the number of sheets to be sent to terminal B, which is the first destination, as "1" in binary notation.
000'', the number of images to be sent to terminal C, which is the second destination, is set to ``0100'' in binary notation, and the image information size is set to A4 and ``1'' to form a command packet. In (2), it is transmitted to the terminal. Since this command packet is irrelevant to the terminal, it is transmitted to terminal C as is in step (3). Terminal C analyzes the command packet, ), and if it is understood, sets rlJ in the response bit of the second destination and transmits it to terminal B in step 4). Terminal B analyzes the command packet, and if it is understood, sends rl to the response bit of the first destination.
Set J and transmit to terminal A in step 5). Terminal A analyzes the command packet, and when it confirms the responses from the first and second destinations, changes the first destination to the terminal's address 0010 and sets it, and leaves the second destination blank. Also,
Set 3, which is the number of sheets to be sent to the terminal that is the first destination, to l'-0010J in binary notation, leave the number of sheets to be sent to the second destination blank, and leave the image size as A4 and set ``1''. The set command packet is transmitted to the terminal at (6). The terminal analyzes the command packet, and if it is understood, sets the response bit of the first destination to "1" and transmits it to terminal C in (7). Since terminal C is unrelated, the data is transmitted to terminal B as is in (8). Terminal B is also unrelated, so in (9) it is transmitted directly to the terminal person. After terminal A confirms the response from the first destination, it sends a command packet to terminal B as the first destination and terminal as the second destination. C is specified, the bit that inquires as to whether the image information is ready for reception is set to ``1'', and transmitted to the terminal using Ql. Since the terminal is irrelevant, it is transmitted as is to terminal C using ell). Terminal C analyzes the command packet, and if it is ready to receive it, sets it to the response bit of the second destination.
It is set to "1" and transmitted to terminal B in Q3. Terminal B analyzes the command packet, and if it is ready for reception, sets the response bit of the first destination to "1" and transmits αj to the terminal person. When terminal A analyzes the command packet and confirms that the first destination B and second destination C are ready for reception, it sets D to the first destination and leaves the second destination blank to prepare for reception. Via asking for completion) Set rIJ, α
Terminal DIC transmission via Xun. The terminal analyzes the command packet, and if it is ready for reception, sets the response bit of the first destination to "1" and transmits it to the terminal C with an alpha signal. Terminal C is unrelated, so it is transmitted directly to terminal B using Qf9. Terminal B
is irrelevant, so it is transmitted as is to the terminal person using aη. When terminal A confirms the response from the first destination, it sets the transmission start bit to "1" in the command packet, and then
Specify terminal B as the destination and terminal C as the second destination, and transmit to the terminal using Ql. a1 ~ (In 211, in the same sequence as above, this command packet is transmitted to terminals C and B sequentially, analyzed, response bit is set, and transmitted to the terminal person.Terminal A transmits to terminals B and C. After confirming the response, specify the terminal as the first destination and set the transmission start bit to “1”.
” and send it to the terminal with (c) 0 (c) ~
In (c), similar to the sequence described above, this command packet is sequentially transmitted from the terminal to O and B, analyzed, a response bit is set, and transmitted to the terminal person. Terminal A is checked for a response from the terminal. Up to this point, terminals B, O, and D, which are transmission destinations, are ready to receive images. Next, terminal A is 1
The first page of the original is read and an image packet is formed.
In (c) to (b), this image packet is sent to the terminal, O,
B are transmitted sequentially. At this time, both terminals C and B capture the image information of the original. When the first image packet is input to the terminal person at (to), terminal A reads the second document and forms an image packet, and (to)
~02, this image packet is sent to the terminal and sequentially transmitted as O and B. At this time, terminal C captures this image information. Terminal B does not capture the image information and transmits it as is to the terminal user.

When the second image packet is input to the terminal person, terminal A reads the third document and forms an image packet, and from (2) to (to), this image packet is sent to terminals O and B. are transmitted sequentially.

Only the terminals take in this image information, and terminal C directly transmits the image packet to terminal B, and terminal B directly transmits the image packet to terminal A. In (b), the third image packet is input to the terminal person.

As a result of the above, one card is sent from terminal A to terminal B, and two cards are sent to terminal C.
Image information for three images was transmitted to each terminal. When the third image packet is input, terminal A specifies terminal B as the first destination and terminal C as the second destination of the command packet, and also sets the bit that asks whether the reception is complete, similar to the sequence described above. 1” and transmits to the terminal at (to). This command packet is sent to the terminal at (to)~Oυ, 0 and B are transmitted sequentially, and when terminal A confirms the responses from terminals B and C, terminal AU specifies the first destination terminal and receives the command packet. Please set the bit “1” to ask if it is completed 4
2 to transmit to the terminal.

This command packet is sent to the terminal at (43 to (48), O and B are transmitted sequentially, and when the terminal A confirms the response from the terminal, the protocol for all image transmission ends. Then (46) Then, the empty packet is transmitted from terminal A to terminal A again.Then, the empty packet is transmitted sequentially to terminals A, D, C!, and B, and waits for the next transmission request.In this way, before transmitting image information, By transmitting image information to a plurality of devices at the same time after all terminals are ready for reception, high-speed transmission that effectively utilizes the transmission speed of optical fibers becomes possible.

Additionally, if a terminal is not specified as a destination by a command packet, this terminal does not perform any processing on the input image packet and transmits it to the next terminal, thereby transmitting a different number of image information for each terminal. This can be done using the same operations as when transmitting image information to all terminals.

Furthermore, since each terminal's response to the control information in the command packet is confirmed before proceeding to the next step, erroneous transmission of image information will not occur.

Next, when an empty packet is transferred on the loop -C, 12
The priority level when more than one terminal has a request to transmit image information will be explained below. As an example, a case will be described in which transmission requests are issued from terminals A and B in FIG. Now, suppose that terminals A and B have transmission requests when an empty packet is input to terminal C.
Then, it is further transferred to terminal B. In other words, the information is input to terminal B before being input to terminal A. As a result, the empty packet is sent to terminal B during the loop connection, and terminal B has the right to be the sender before terminal A.

In this way, the terminal connected to the output side of the terminal that currently outputs empty packets has the highest priority, and the priority gradually decreases according to the order in which empty packets are transferred, and the terminal that is connected to the input side of the terminal that outputs empty packets has the highest priority. terminal has the lowest priority. Also, if an image is currently being transmitted and another terminal receives a transmission request at this point, the current transmission operation ends and the terminal that was the source of the image information outputs an empty packet. The terminal connected to the output side of this source has the highest priority, and the terminal connected to the input side has the lowest priority. That is, at the time when the previous transmission of one image information is completed, the priority of the loop related to the next transmission is automatically determined based on the previous transmission source. As mentioned above, the priority changes from moment to moment.

FIG. 7 shows a circuit embodiment of a terminal of an image transmission system according to the present invention. Reference numeral 11 denotes an optical-to-electrical converter (hereinafter referred to as an 0/E converter) provided at the input section of the terminal, which converts information input as an optical signal from a signal transmission line using an optical fiber into an electrical signal. 12 is a command/image discrimination circuit which determines whether the input packet is an image packet or a command packet by ANDing the electrical signal input from the OA converter 11 with the identification signal S added before the packet and the clock as described above. If it is an image packet, it outputs an rlJ signal to line 13, and if it is a command packet, it outputs a "1" signal to line 14. Also, a packet from which the identification signal S has been removed is output to line 15. 1
Reference numeral 6 denotes a recording unit that records images based on input image packets, and an image packet that reads the original and converts it into electrical signals.

This is the reader/printer section that forms the paper. Line 17 is a non-source signal line to which a "1" signal is always output when this terminal is not the source of image information. 18 and 19
is an AND circuit, and the "1" signal on line 13 from the command/image discrimination circuit 12 and the "1" signal of the non-source signal on line 17 are input to the AND circuit 18.

If so, the image packet input by line 15 is output on line 15. Also, the AND circuit 19 is supplied with “1” on the line 13 from the command/image discrimination circuit 12.
” signal is input, outputs the command packet input by line 15 on line 21. If the terminal is the source of image information, the non-source signal on line 17 is a "0" signal, which prohibits output of input image packets to the line. This results in 1
The 0-input capacitor prevents the image packet transferred from the terminal of cap-C from being outputted again.
If the image packet is output on line 20, the image packet is branched into a line input to the reader/printer device 16 and a line input to the delay circuit 22. The delay circuit 22 outputs the image packet to the next terminal.
Since the identification signal must be added before the image packet, it is provided to delay the image packet for the formation of the identification signal S. Reference numeral 23 denotes an image identification signal generation circuit which, when receiving the line 1 a rtl signal, generates an identification signal to be added to the front of the image packet currently being input. 24 is an OR circuit that adds the identification signal S of the "1" signal output from the image identification signal generation circuit 23 to the image packet output from the delay circuit 22, and also adds the league signal when the terminal is the source of the image information. Then, an identification signal S is added to the image information outputted from the printer device 16 on line 33 and outputted on line 25.

Reference numeral 26 is an electrical-to-optical converter (hereinafter referred to as E10 converter) provided at the output section of the terminal, which converts the image packet input via line 25 into an optical signal.

It is transmitted to the next terminal using optical fiber as a medium.

On the other hand, if the input; l'J packet is a command no (kerat), the command no (kento) output on line 21 is input to the input command register 27.

The input command register 27 stores all command packets of 32-bit configuration. 028 is a command analysis and generation circuit, which outputs an image packet discrimination signal on line 13 and a command number (kerat discrimination signal) output on line 15. 0 input command register 26 into which
When it is determined that all 32-bit commands (kerat) have been input, all 32-bit commands (-kerat) are taken in, the contents are analyzed, and response bits and specified pits are formed as necessary as described above. Then, all 32 bits are set in the output command register 29 at the same time.Furthermore, if the aforementioned terminal is not the source, a non-source signal is output on line 17.30 is a command identification signal generation circuit, which is connected before the command analyzer). An identification signal S is formed to be added to the identification signal S. 31 is an OR circuit which is inputted from the output command register 29, but before the ζnd packet, an identification signal S from a command identification signal generation circuit 30 is added and outputted to a line 32. The line 32 is input to the converter 26, where it is converted into an optical signal in the same way as the image packet, and transmitted to the next terminal via the optical fiber used to transmit the image packet. The four switches SW1 to SW4 are used to set the address of the terminal, and the switch SW5 is used to set whether or not command packets can be issued at system startup, and is the only switch in the system. It is operated on the terminal. These five switches are preset when the system is installed, and there is no need to re-operate them unless a special problem such as system improvement occurs. Figure 8 is shown in Figure 7. 2 is a detailed circuit diagram of the command analysis and command generation circuit 28. FIG.

60 is an address bus, 61ij data bus, 62 is a read signal line, 63 is a write signal line, 40 is an eighth
The central control unit (hereinafter referred to as CPU) that controls the operation of the circuit shown in the figure is, for example, an Intel 8085 microcomputer. Reference numeral 41 denotes an interrupt controller, such as an Intel 8259, which inputs an interrupt signal to the CPU 41 for controlling interrupts of the CPU 40. The CPU 40 operates upon receiving an interrupt input from the interrupt controller 41. The signals input to the interrupt controller 41 are a signal (INTI) indicating that the timer for detecting loop break has elapsed for a predetermined period of time, and a signal (INTI) indicating that the timer has expired, and a signal (INTI) indicating that a key on the operation unit provided in the device has been operated. signal (INT
2).

The command discrimination signal (INT3) and image discrimination signal (INT4) from the command/image discrimination circuit 12 in FIG.
). When these four types of signals are input, the interrupt controller 41 sends an interrupt signal lNTR to the CPU 40.
is output, and CPU4Q starts operating. 42 is CPU
Address information on the address bus 60 output by the address bus 40.

This is an address decoder that accesses each section that is controlled by the CPU 40. 43 is a read-only memory (ROM) in which an operation control program for the CPU 4Q is stored. 44 is a random access memory (RAM) having a storage space as shown in Table 1. 045 is an event timer for detecting the breakage of the loop described above. 046
is the operation unit of the terminal, 47 is a key provided on the operation unit 46,
A key and display controller that controls input/output of a display, etc. is, for example, Intel's 8279. 47%48 is the input/output port (170 boats), for example Intel 8255. The I10 boat 47 receives operation signals of five switches SWI to SW5 provided in the command analysis and command generation circuit, and a signal SIZE from the reader and the printer device 16 indicating the size of the recording material requested by the printer device. , a signal POK indicating completion of operation preparation of the printer device, and a signal PEND indicating completion of operation of the printer device. The I10 port 48 receives a command signal CMDS for generating a command discrimination signal in the command discrimination signal generation circuit 30, a signal PRED for instructing the printer to prepare for operation, a signal PST% for starting the printer, and 29 as shown in FIG. The output command register 27 is an input command register.

Table 1 AM TABLE Master flag Channel shop line check flag Address 1 Number code area Line normal flag Address 2 〃 Line abnormal flag Address 3 〃 Destination (I) flag
Address 4NFiLL27 rasog Destination address code FiLL 3 flag Original size repeat flag Received number of sheets area Send request 7 lag Maximum number of sheets area source flag Send command/packet reception source 7 lag
Reception command/packet reception completion flag Figures 9 to 13 show command analysis and command generation circuit 2
8 is a control 70-chart diagram of the 0PU40 of No.8, and these programs are stored in the ROM 43 in advance.

The 70-chart diagram of n et al. will be explained below. When the power is turned on to the terminal, the above-mentioned loop disconnection detection is first performed. Let me explain this.

FIG. 9 shows power-on 70- When the power of the 0 terminal is turned on, the interrupt controller 41, event timer 45, key and display controller 47, I10 controller 47, 48 of FIG.
Then, the RAM 44 is initialized. Thereafter, in step 71, the I10 controller 47 is read and the terminal is activated by determining whether the input of bit 5 is "1", that is, whether SW5 in FIG. 7 is operated. At system startup, it is determined whether the master terminal is capable of issuing command packets. If the bit 50 input is "1", the terminal is a master terminal, so a master flag is set in the RAM 44; otherwise, the master flag in the RAM is reset.

Next, in step 72, bit 1 of the I10 controller 47
-4 in the channel number area of RAM 44. That is, the address of the terminal set by SW1 to SW4 is stored in R and AM44. Then, in step 73, a predetermined timer value is set in the event timer 73 to start timer operation, and a line check flag is set in the RAM44. In step 74,

Determine whether or not the master flag is set in the RAM 44, and if it is set, set 0, which is an empty packet, in the output command register 29, and if the master flag is not set, end the power-on 70-. 0 After this, if the loop is normal without any breaks, and if it is the master terminal, the command packet it issued will complete the loop before the event timer 45 times up.
It is input repeatedly. In addition, for terminals other than the master terminal, the command packet issued by the master terminal is detected by the event timer 4.
It is input before the time of 5. Therefore, if the loop is normal, the command discrimination signal INT3 is input to the interrupt controller 41, which is further notified to the interrupt terminal of the CPU 40, and the 0PU40 operates.However, if the loop is broken again, an event occurs before the command packet is input. The timer 45 times up. Then, a time-up signal lNTl indicating this time-up is input to the interrupt controller 41, which is further transmitted to the 0PU400 interrupt terminal, and the 0PU40 operates.

Figures 10A to 1OJ are command discrimination signal interrupt routines when the command discrimination signal NT3 indicating that a command packet has been input to the terminal is input, and the routine in Figure 10A is used to detect loop breakage. Since the line check flag was set in step 73 of the power-on flow in Figure 9, step 80
In step 81, the loop 1 flag indicating that a command packet has already been input has not yet been set, so the loop 1 flag is set. In step 82, input command register 27
Loads the command packet input into the received command packet area of the RAM 44. In step 83, it is determined whether or not the command packet loaded into the RAM 44 is an empty packet. In this case, since it is an empty packet, the process proceeds to step 84, and the transmission request 7-) knob is set, which indicates that the terminal has a transmission request. determine whether it is. In this case, since there is no transmission request, the process proceeds to step 85, where an empty packet is formed in the transmission command packet area of the FLAM 44, and in step 86, the output command register 29
Load into. Then, in step 87, the event timer 4
A predetermined timer value is set to 5, the timer operation is started, and the command discrimination signal interrupt routine is ended. After that, when a command packet is input again before the time-up of the event timer 45, the command discrimination interrupt routine is started again. At this point, the loop break detection is finished, and in step 81, the loop is judged to be normal. is R
, Since the loop 1 flag is sent to AM44, reset the loop 1 flag, further reset the line check flag, set the line normal flag, and reset the abnormal flag.
4, and if no transmission request is input to the terminal, an empty packet is loaded into the output command register 29 and the timer operation of the event timer 45 is started again.0 However, here When the event timer 45 times up before the command packet is input, the time-up signal lNTl is input to the interrupt controller 41 and the timer interrupt routine of FIG. 11 is called. In step 50, if the disconnection of the series is not detected by the routine shown in FIG. 10A and the loop is normal, a line flag is set in the RAM 44. End the interrupt routine 0 However, if the line flag is not set, it is determined that no command packet was input before time-up, and the line error flag is set in the RAM 44 and the process proceeds to step 51 0 In step 51, the terminal is Determine whether the master flag indicating that it is a master terminal is set 0
If the terminal is a master and the master flag is set, an empty packet is set in the output command register 29 and the process proceeds to step 52.If the terminal is not the master, the process proceeds to step 52.0 At step 52, a predetermined value is set in the event timer 45. Set the timer value and start timer operation. In this way, if the terminal is the master, when the time-up occurs before inputting the command packet, the command (kerato) which is an empty packet is output again and the timer operation of the event timer 45 is started at the same time.If the terminal is not the master, Start the timer operation of the event timer 45 again 0 In this way, repeat the loop disconnection detection several times, and if the command packet is still not input normally even after the predetermined number of detection operations, it is certain that the loop is broken. It is determined that there is a break in the loop, and activates the alarm means etc. provided in each terminal.In addition, since each terminal is configured to individually detect a break in the loop, if there is a break in the loop, The cutting position can be determined accurately.0 FIG. 12 shows a key-in interrupt routine when a key input signal INT2 indicating that a key on the operating section 46 has been operated is input from the operating section 46. The information is
In step 90, the information of the entered key is set to R, AM, which contains four types of instructions: the destination of the image information, the number of image information to be sent, the size of the image information to be sent, and an instruction to start sending.
44. In other words, when the destination address key is entered, the address code is set in the RAM 44. Also, if the transmission number key is entered, the RAM 4 corresponding to the destination address
Set the number of sheets in the number of sheets code area of 4.O still set the size in the document size area. After the above three types of information are entered, when the transmission start key is entered, R
Check addresses 1 to 4 in order to see if the number of sheets has been set in the areas corresponding to the four sending addresses of AM44. The number of sheets is set in the address bit of the first destination of the transmission command packet, and the number of sheets is set in the number of transmission bits, and then the transmission address confirmed to have the number of sheets set is set in the address bit of the second destination of the transmission command packet. is set to the transmission count bit. Incidentally, if a destination for which the number of copies is set is confirmed, a repeat flag is set in the RAM 44. If the destination is not confirmed any further, the document size bit and destination address bit of the transmission command packet are further set. Then, the send request 7 rasog of the RAM 44 is sent to 0. Here, the send command packet area of the RAM 44 is set with a send command packet to be output when an empty command packet is received. The command number (kerato) based on the destination address, number of sheets to be sent, document size, etc. is formed in the sending command packet area in the RAM 44, and the F t LL 2 flag is R.
Indicates that information regarding the terminals with addresses 1 and 2 has been set in the transmission command bat area in AM44, and
LL3 indicates that information regarding the terminals with addresses 1 and 3 or 2 and 3 has been set in this area. In this way, a command packet is formed in the kerato area of the send command in RAM 44, and the send request flag is set. When an empty packet is input to a terminal, a command discrimination signal interrupt routine is called by the command discrimination signal INT3. Then, this terminal becomes the source of the image information, and starts the protocol necessary for transmitting the image information to the destination.0 Below, the operation of the source terminal will be explained. 0 Refers to the command discrimination signal interrupt routine of
When an empty packet is input to a terminal in which the rasog is set, the routine shown in FIG. 10A is called by the command discrimination signal INT3. Since the line check flag has already been reset, the process advances to step 82 and loads the command input into the command register into the received command packet of R and AM44. Then, in step 83, the content is determined and it is an empty packet, so the process goes to step 84 and checks whether the transmission request flag is set. In this case, there is a transmission request, and the RAM 44
Since the transmission request flag is set, the process proceeds to step 92.0 At step 92, the transmission request flag in the RAM 44 is reset, and a sender flag indicating that the terminal has become the sender is set in the RAM 44, and the process proceeds to step 86. In step 86, the command packet that has already been formed in the transmission command packet area of the RAM 44 based on the data input from the operating section is loaded into the output register 29.

Then, while transmitting the command packet, a predetermined value is set in the event timer in step 87 to start timer operation, and the routine of FIG. 10A is ended. At this point, a command packet with bits set indicating the destination, the corresponding number of transmissions, the source, the original size, and the line connection is transferred onto the loop. The source terminal then waits for this command packet to pass through all terminals and be input again.

When a command packet is input again to the source terminal, the routine shown in FIG. 10A is called by the command discrimination signal INT3. This command packet contains information related to transmission and a response from the destination. Therefore, , it is determined in step 82 that the command packet loaded into the RAM 44 is not an empty packet, and the process proceeds to step 88.
Since the source flag is set in the RAM 44, the process advances to [F] in FIG. Then, in step 101, the command packet in the reception command packet area of the RAM 44 includes a reception preparation completion bit, a transmission start command bit,
Then, check whether the transmission completion bit is set. In this case, since these three types of bits are not set, the process proceeds to step 102. In step 102, it is determined whether or not bits corresponding to the first and second destinations are set in the received command packet area. If they are set to 0, each bit is reset and the process proceeds to step 103. , if not set, the number code area of the RAM 44 corresponding to the destination is set to O, each response bit is reset, and the process proceeds to step 103.

In step 103, it is checked whether the repeat flag is set in the RAM 44 in the key-in interrupt routine shown in FIG. If the repeat flag is set, it is determined that there is another destination for which the number of sheets can be set, and in step 104 it is checked whether the FiLL2 flag is set. 0 or F to see if it is set
If the iLL2 flag is set, step 104
Assuming that the information to the destination corresponding to addresses 1 and 2 was set in the previous command packet, address 3
Check whether the number of sheets is set for both addresses 3 and 4. In this case, if the number of sheets is set for both addresses 3 and 4, set the address 3 to the first destination bit of the receive command packet area in RAM 44 and the number of sheets. Set the transmission count bit, set address 4 to the second destination bit, and set the number of sheets to the transmission count bit. is set to the first destination bit of the received command packet area, and the number of sheets is set to the transmission count bit to 0. Then, the FiLL2 or FiLL3 flag is reset and the process proceeds to step 106.0 In step 106, the repeat flag is reset to 0. Then, the command packet set in the RAM 44 is loaded into the command register 29, and the event timer 45 is activated. However, if the repeat flag is not set in step 103, the process proceeds to step 107.In step 107, it is checked whether the RAM 44 has the number of copies set for destinations 1 to 4. If it is the sender terminal, the number of sheets has been set, so the process proceeds to step 108, and first a bit is set in the RAM 44 to inquire whether the reception preparation for the reception command packet is complete. Then, in step 109, it is determined whether or not the number of sheets is set in the area corresponding to each address.
If the number of sheets has been set, set that address to the first and second destination address bits in the receive command packet area of the RAM 44 according to the flowcharts in Figures 10D to 10G corresponding to each address. , if the number of sheets is set in three or more terminals, set the repeat flag 0 and proceed to 0 RAM
44 is loaded into the output command register 29, and the event timer 45 is activated. In this way, the command packet with the bit set to inquire about the completion of reception preparation is output onto the loop. The source terminal then waits for this command packet to be input again as described above.

Next, when a command packet is input, the routine of FIG. 10A is called by the command discrimination signal INT3, and if the reception ready bit of the received command packet is set, step 10 of CxIA
1 to [F] in Figure 10H. And step 1
If the destination response pit should have been set in step 01 but it is not, load the input received command packet into the output commander register 29 and return to step ① to load the same command packet again. Output. If the destination response bit that should have been set is set, the response bit is reset in step 111, and it is determined in step 112 whether the beat flag is set in R, AM 44. If it is not set, in step 113 the reception ready bit of the reception command packet is reset, the transmission start command bit is set, and the process proceeds to ◎ in Fig. 1oC. and step 10
In step 5, it is again sequentially determined whether or not the number of sheets is set in the area corresponding to each address in the RAM 44. Then, set the address in the receive command packet area,
Return to step (3) and output the command packet sent to 9RJAM44. Q. If the repeat flag is set in step 112, it is determined in step 114 whether the FiLL2 flag is set, and if it is set, the previous command packet is received to the destination corresponding to addresses 1 and 2. Assuming that the bit inquiring about the completion of preparation is set and the response bit is obtained, it is checked in step 115 whether or not the number of sheets has been set at addresses 3 and 4. and,
Set the addresses in the address bits of the first and second destinations in the RAM 44, reset the repeat flag, and return to step (3) to receive the command packet with the bit set in the fiRAM 44, inquiring whether reception is ready for the new destination. Output.

Next, when a command packet with the transmission start command bit set is input, the command discrimination signal INT3 causes the first
The routine shown in Fig. 0A is called, and the process proceeds from step 101 in Fig. 100 to (2) in the 10th engineering drawing. In FIG. 1, it is determined in step 116 whether the response bit for the transmission start command is set, and if it is not set, the process returns to (2) and sends out a command packet containing the same information again. If the response bit is set, it is determined in step 117 whether the repeat flag is set. If it is a cent, proceed to ■ in Figure 10H. If set -C, proceed to step 118 and RA
Step 102 for resetting the transmission start command bit in the received command packet area of M44 and further instructing the start of the league.
Set bit 3 of . Then, among the set numbers corresponding to each destination address set in the RAM 44, the maximum number is set in the maximum number area of the RAM 44.

As described above, when a response from the destination to the transmission start command from the source is confirmed, the source terminal starts transmitting image information.

That is, an image packet formed by reading a document is output from the transmission source. When the image packet returns to the source terminal via each terminal, the image discrimination signal interrupt routine shown in FIG. 13 is called by the image discrimination signal INT4. If the terminal is the source, the process proceeds to step 120, where 1 is subtracted from the maximum number area, and when the content of the maximum number area becomes 0, it is assumed that the transmission of the image packet has been completed, and the process proceeds to step 121.

Then, in step 121, l10
Reset bit 3 of 2, and set a bit in the receive command packet area to inquire about reception completion.

and go to 0 in Figure 100. And... step 10
At step 5, the address of the terminal for which the number of sheets has been set is placed in the first or second destination pit of the received command packet, and the process returns to 0 to output the command packet set in the RAM 44. Also, if the value in the maximum number of images area does not become 0 in step 120, the image packet is output again.O The value in the maximum number of images area becomes 0, and the source terminal that outputs the command packet with the pit set to ask about completion of reception. waits for response bits from the destination. When this command packet is input, the command discrimination signal interrupt routine shown in FIG. When a command packet is input, it is determined in step 101 and the process proceeds to Figure 10. If the flag is not set, return to step 3 and send out a command packet with the same information again. If the response focus is set, proceed to step 123 and determine whether the repeat flag is set. If so, proceed to ■ in Figure 10H and ask the remaining destinations whether the reception is complete.If the flag is not set, proceed to step 124, set the transmission command packet to O, and proceed to ■ in Figure 10A.Here, , all images have been sent from the source, and empty packets are sequentially transferred onto the loop again.

Next, the operation of the destination terminal will be described.

Assume that the line check is completed, the source outputs a command packet containing information specifying the destination, and this command packet is input to a terminal other than the source. As a result, the command discrimination interrupt routine of FIG. 10A is called by the command discrimination signal INT3. In step 80, since the line check flag has already been reset, the process proceeds to step 82, and the input command packet is written into the received command packet area of the RAM 44. The process then proceeds from step 83 to step 88, and since it is not the originator, the process further proceeds to step 89. Step 89
Then, it is checked whether the first destination address bit of the received command packet matches the channel number of the own terminal set in the RAM 44. If it matches, RAM4
Set the receiving source flag No. 4 and proceed to ① in FIG. 10B. If the first destination address bits do not match, then in step 90, a match with the second destination address bits is checked. If they match, the process proceeds to ■ in FIG. 10B. If they do not match, that is, if it is not specified as either the first or second destination, the process advances to step 91 and the received command packet is output as is to the command register 2.
9, reset the receiving source flag in the RAM 44, and proceed to step 87, set a predetermined timer value in the event timer, start the -C timer, and output an empty packet. If it is specified as the first or second destination as described above, proceed to step 2 in FIG. 10B (0).Then, it is determined in steps 93 to 95 what the received command packet is for.

In other words, if the first question is whether reception preparation is complete, l101
Step 10: reads the data and indicates whether printing is possible or not.
Look at the Biwa door signal in No. 1. If the printing operation is possible, proceed to ◎ and check in step 99 whether or not the receiving source flag is set. If it is set, it is assumed that the own terminal is the first destination, and the first destination response bit of the received command packet is set. Load the sending command into the packet area.Also, if the receiving source flag is not set, assume that your terminal is the second destination, and set the receiving command's response bit (Kerato's second destination response bit to 0), and then print the command. Set pit 2 of l102, which is the preparation command for
44, the process proceeds to FIG. 10A, 00, outputs to the loop, and starts the timer.

However, if the printing operation is not possible, proceed to ◎ and proceed to ◯ in FIG. 10A without setting the response bit of the own terminal and directly output the received command packet.

Second, if the received command packet instructs the start of transmission, the printer device is made ready to accept the image signal in step 94, and the process proceeds to (2), where the response bit is set.

Also, if the third question is to inquire about reception completion, step 95
Then read l101 and check the signal of bit 8 of l101 indicating whether the printing operation has ended or not. If the print operation is completed, proceed to ◎ and set the response bit. If the printing operation is completed and there is no -C, proceed to ◎ and do not set the response bit.0 Also, if the received command packet does not ask any of the three questions mentioned above, read l101 and set it in the printer device in step 97. It is determined whether bit 6 of l102, which indicates the size of the recording material being used, is equal to the size specified by the received command packet. If they are equal, the process proceeds to step 99 and the response bit is set; if they are not equal, the command packet is output without setting the response bit.

In FIG. 10B, a command packet with the focus set in response to the transmission start command is sent out, and when this command packet is confirmed by the sending terminal, an image packet is sent.

When an image packet is input to the destination terminal, the image discrimination signal interrupt routine shown in FIG. 13 is called by the image discrimination signal INT4. In step 119, since this is the destination terminal, the source flag is not set.

If the image packet corresponding to the set number of images has not been received, the reception completion flag is not set in the R, AM 44, so 1 is subtracted from the received image number area of the RAM 44, and the number in the received image number area becomes O. See if it works or not. If it becomes 0, the reception completion flag is transferred to RAM4.
4, and further resets bit 2 of l102, which is a signal output terminal for copying operations.

In this way, the destination terminal is an image packet.

When the number of sheets is input, 1 is subtracted from the received number area of R, AM44, and when the value becomes 0, it is determined that reception is complete, and the RAM is
The reception light completion flag is set in 44 to finish receiving the image packet. Then, a response bit is set for the next input reception command packet in which the bit inquiring about reception completion is set.

As explained above, according to the present invention, it is easy to generate an identification signal for discriminating information on a common optical fiber,
Further, the identification signal judgment circuit can be easily constructed. Furthermore, the time required for the determination is short and does not interfere with high-speed transmission.

Although this embodiment has described a system in which four terminals are connected, the number of terminals may be other than that.
However, the present invention is applicable to terminals that have only one of the functions, and even to terminals that have other functions such as a display.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the connection of a loop transmission system using optical fibers to which the present invention is applied, FIG. 2 is a diagram showing the configuration of an image reading section, FIG. 3 is a diagram showing an image packet, and FIG. 5 is a diagram showing the contents of the command packet, FIG. 6 is a diagram showing the procedure of global calls related to image transmission, FIG. 7 is a block diagram showing an example of the terminal circuit, and FIG. Figure 8 is a detailed circuit diagram of the command analysis and command generation circuit, Figures 9 to 13 are CPU control flowcharts, 12 is a command/image discrimination circuit, 27 is an input command register, and 28 is a command analysis circuit. 29 is an output command register, 40 is a CPU, 41 is an interrupt controller, 43
is ROM. 44 is a RAM. Applicant: Canon Co., Ltd. (timer official approval, 5 μm)

Claims (1)

[Claims] (1) A first transmission path that transmits multiple pieces of information, a second transmission path that synchronizes with the above information or transmits a four-way signal, and adds an identification signal to the information transmitted by the first transmission path. ,
iii. A transmission system characterized in that information on the first transmission path is discriminated by transmitting a clock signal synchronized with the identification signal through the second transmission path (2. 2. The image transmission system according to item 1, wherein the information is discriminated based on the level of the identification signal.