JPS61105142A - Communication interface for video display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for connecting a user input/output terminal device to a data processing device. Such a connection may be used if one data processing device supports a large number of user terminals or only one user terminal a' located at a distance from the data processing device. is necessary. A communication link between the data processing equipment and the user terminal equipment is necessary to provide the necessary interaction between these equipment. The present invention relates to this communication leak.

OBJECTS AND SUMMARY OF THE INVENTION The types of user terminals to which the present invention is applicable include a variety of input and output devices. The primary output device used in such user terminals is a video display device. Video display devices are typically Rusk scan cathode ray tubes that provide graphical and image information to the user. The terminal device may also include a tone generator for generating tones useful for audible alarms and the like. Such user terminal equipment further includes some type of speech synthesis device;

There are cases where all audio output is generated mechanically and is understood by naive users. If there are restrictions on the type of mapped data, one or more display lamps controlled by the data processing device may be biased.

The type of user terminal device to which the present invention is applicable usually includes:
A manual typewriter type keypad is used as the primary human power device. The keyboard is used to press one or more keys to compose text messages to be transmitted to a data processing device. Another type of input device that is widely used is the mouse.

A mouse is a pointing device shared with a video display screen. A cursor or pointing device on the screen moves in response to movement of a mouse on a surface, such as a desk, that is in direct contact with a user terminal. This type of mouse also includes one or more user-operated switches by which condition signals can be transmitted from the user to the Central American processing device. In addition, such a user terminal device may include a microphone for receiving verbal communication, which is understood in conjunction with a voice recognition device.

It can be seen that even the simplest type of user terminal equipment requires bidirectional communication. When a data processing device transmits video data to a customer terminal, this communication must occur at a high bit rate. In contrast,
Data transmitted from a user terminal device to a data processing device, such as data from a keyboard, typically occurs at a slow rate. Accordingly, the type of interface to which the present invention pertains includes bidirectional communication with varying bit rates.

There are mechanical and electrical dispersions for this type of communication link. First, it is necessary to reduce the weight and volume ti of the communication links between these devices. Minimal weight and volume facilitates installation of communication links. It is also desirable that the cable used for this purpose be flexible and able to adapt well to the requirements of any installation path.

Such communication links are typically installed in offices used by technicians or other technicians. Other single child devices also
Usually used in such places.

Consider the electrical requirements for such a communication link. Electromagnetic interference (KM engineering) and radio frequency interference (RP)
■) are emitted from such communication links.

This is the type of radiant energy that is emitted. Particularly when high bit rates are required, high frequency signals are required in the communication link and special measures must be taken to minimize the amount of radiated energy. This total minimization of radiated energy minimizes the interference caused by this particular communication link to other electrical devices within the same area.

For similar reasons, it is desirable to provide a type of communication link that minimizes electrostatic discharge (ESD). Data processing equipment and user terminal equipment are typically made of metal oxide semiconductors (M
OS) configured using the device. These M.O.
8 devices are static sensitive and susceptible to injury from electrostatic discharge. Therefore, it is highly desirable to have a general communication link that minimizes the number of silent discharge sessions.

Another problem with communication links is the gap between ground movement. 1 High-frequency copper wire is usually low mV.
Connect to the chassis ground terminal. When two chassis are located apart, there is a possibility that they will be connected to different branches of the power supply line and have different chassis ground potentials. In such a case, unnecessary current may flow through the thin wire, causing problems.

(Example) FIG. 1 shows the general configuration of an apparatus used in a preferred example of the present invention. This device includes a central processing unit 1110,
Graphics controller 120 and user terminal 130t-included. The central processing unit 110 has a communication link 1
Graphink Controller 1 via 12 and 116K gold
20 and performs all bidirectional communication. Similarly, graphics controller 120 has full bidirectional communication with user terminal fit 130 via communication links 122 and 126. A dashed line 140 surrounds the central processing unit 110 and graphics controller 120. This break m 140 is shown in the package fl' included in one housing. When the computer group *ioo is used by only one user, it is desirable to house all of these devices in k1 cases. In that case, communication links 112 and 116 and communication links 122 and 126 can be housed within one housing, and the mechanical and electrical problems for running these communication links are greatly simplified. However, as the computer system of the preferred embodiment becomes larger, these six
It is conceivable that it will be impossible to accommodate all three devices in the same housing. When a data processing device becomes too large to be accommodated in a single housing, it becomes necessary to use multiple housings and connect these housings. As shown in FIG. 1, there is a natural functional division between the 1C1 central processing unit, graphics controller, and user input/output terminals. [Thus, these devices can be arranged in six separate nine housings or differently in two housings. One method is to house the central processing unit and the graphics controller in one casing, and to house the user terminal in a't-another casing, as shown in FIG. Another method is to house the central processing unit 1 in one housing, and house the graphics controller and user terminal device in another housing. Since the data processing system of the preferred embodiment of the present invention uses a high resolution video display device, communication between central processing unit 110 and graphics controller 120 requires high data rates. Therefore, the central processing unit 11
0 and the GraphInk controller 120 in the same housing.

In the preferred embodiment, central processing unit 110 and graphics
The controller 120 is housed in the same housing. Accordingly, communication links 122 and 126 are provided from the housing 140 to the user terminal 130. In this case, communication links 122 and 126 experience the mechanical and electrical problems discussed above.

FIG. 2 illustrates a communication link 12 according to a preferred embodiment of the present invention.
2 and 126 are shown.

Transmitter 210 and receiver 220 are located within graphics controller 120. On the other hand, the receiver 23
0 and the transmitter 240 are located within the user terminal 61130.

Transmitter 210 transmits data over communication link 122 to receiver 230 . The transmitter 210 is a video
11. Receive keyboard input (controlling keyboard display or controlling keyboard configuration) 212 and signal tone input 213'.

Receiver 230 receives these data over communication link 122. The receiver 230 receives video data 231,
Keyword data 232 and signal tone data 233 are separated on the output side and added to a corresponding portion (not shown) in the user terminal device that utilizes all of these data. Receiver 230 also transmits a clock signal 235 derived from the signal received by communication link 122.

In a preferred embodiment according to the invention, communication links 122 and 1
26 are both made up of original fibers. Using original fiber for this communication link minimizes mechanical and electrical problems with the communication link. First, the original fiber
Since the pull is extremely thin, it is relatively lightweight and has a small volume. These cables also have superior flexibility compared to prior art copper coaxial cables. Thus, the original fiber cable contributes to solving mechanical problems associated with such communication links.

Furthermore, the original fiber cable also helps solve electrical problems associated with such communication links.

There is no vibration wJ% flow in the original fiber cable.

This absence of oscillating currents, in contrast to prior art copper coaxial cables, is a factor that makes fiber optic cables km advantageous. The main causes of electromagnetic interference (1!!M) and radio frequency interference (R11') are their oscillating currents. The original fire cable is essentially
Reduce this cause of electrical problems. Also, the original fiber cable is non-conductive. Therefore, the chance of injury due to electrostatic discharge (part D) from the original fiber cable (as opposed to the prior art copper coaxial cable) is substantially reduced.

Such original fiber links are also prone to static electricity and are the most likely to cause interference with user terminal equipment? Care should be taken to prevent electrostatic discharge paths between the central processing unit and the central processing unit.

A receiver 220 within graphics controller 120 receives data over communication link 126 from a transmitter 240 located within user terminal 130 . The transmitter 240 includes keyzai data 241 and mouse data 2.
42 and audio data 243 are added. Transmitter 240 also receives clock 235 from receiver 230. Transmitter 24
0, pick up the input data along with the clock signal,
A transmission signal is sent to the communication link 126 in a format required by the communication link 126. This signal is applied to a receiver 220 within graphics controller 120.

Receiver 220 converts the signal from communication link 126 into its component signals: keyboard data 221, mouse data 222, and audio data 223. This data is applied to central processing unit 110 and processed individually.

From Fig. 3 (At to Fig. 6 (0), communication link 12
A preferred embodiment of the type of communication from the graphics controller 120 to the user terminal 130 according to FIG. The third u+ (At denotes the type of data transmitted by communication link 122 during a normal horizontal scan period. In the preferred embodiment, the video signal is transmitted in digital form. In a monochromatic display device, the display Each pixel of the digital video data is represented by one bit.This digital video data is
transmitted in a set of horizontal scan lines. FIG. 6 (Bl) shows the format of the communication transmitted during the vertical retrace period. The final diagram (0) shows the format of the coded data 320 transmitted during the horizontal did.

Signal 310 is transmitted over communication link 1 during a normal horizontal scan period.
represents the portion of data transmitted by 22. This signal 310 is comprised of uncoded data 315 and coded data 320.

Preferably, the uncoded data 315 is one bit for each pixel on each horizontal line in the video display. For example, a "zero" at a particular pit location causes the corresponding pixel on that horizontal line of the video display to be black. On the other hand, a 1'' in that bit position is
Makes the corresponding pixel on the screen white. This is in accordance with the preferred embodiment using digital video signals. Communication link 122 is also capable of transmitting all analog signals, including all gray scales. The required bit rate for the communication link is determined primarily by the number of pixels on the video screen and, therefore, the number of pit locations in the uncoded video data 315. For example, each i, o o
For a high-quality video screen with 1,000 horizontal &''k pixels, each uncoded video data portion 315 must contain 1,000 pixels.
Also, to transmit the entire video screen, 1,0
00 uncoded video data portion 315 needs to be transmitted. Therefore, each video screen will contain approximately one million video screens. To provide a flicker-free display of moving objects, it is generally considered necessary to transmit a complete 60 frames per second. Therefore, the data rate for such high quality video screens will be at least 60 million (60 x million) bits per second.

The coded data 320 of the signal 310 includes keyboard data, signal tone data, and other incidental data. This coded data 320 is further shown in FIG. 6 (C1).

Signal 330 shows the signal transmitted by communication link 122 during the vertical retrace interval. As is well known to those skilled in the art, during the vertical retrace period of a rask scan image, the cathode ray spot is
Return to the upper right corner. This time period is equal to several horizontal scan periods, during which incoming video data is ignored. Therefore, the video data transmitted during this period of the scan cycle is not Me. In the preferred embodiment, a square wave signal 335 is transmitted during this vertical blanking period. In addition, the coded data 320 is transmitted at the end of each horizontal scanning line constituting the vertical retrace period, just as in the case of the normal horizontal scanning signal 310.

Full details of the coded data 320 are shown in FIG. 6 (CI).

Coded data 320 includes synchronization pattern 321, vertical synchronization 322) key size data 323, audio data 3
24, signal tone data 325 and test data 326. Synchronization pattern 321 is used to notify the user terminal of the end of a horizontal scan line. In analog video systems, the horizontal synchronization signal is communicated as an analog signal outside the range of allowed video signals. In the preferred embodiment video system, video data is transmitted as a digital signal. Therefore, it is necessary to provide other means for identifying the ends of horizontal scan lines.

The PL period pattern is a predetermined set of bits. As will be described in detail later with respect to FIG. 5, the receiving device within the user terminal detects this predetermined set of bits in response to the synchronization pattern 321, and thereby detects the coded data. 320 decoding begins.

Vertical sync 322 performs a similar function to sync pattern 321. Vertical line 1322 is used to indicate when a frame reset is required.

The remaining portion of coded data 320 is a graphic
This corresponds to data transmitted from the controller 120 to the user terminal device 130. Keymate data 323 serves to control the keyboard indicator sound and also controls the configuration of the keyboard. Audio data 324 is used with a speech synthesis circuit. Audio data 324 specifies a particular synthesized speech generated by user terminal device 130. Similarly, tone data 325 is used with an audible tone generator. The beep sound data 325 is used in the user terminal device to instruct the type of sound generated by the beep sound generation device. User terminal equipment [113
User terminal device 130 to test various points of 0.
It is used by

Those skilled in the art will appreciate that the above description of coded data 320 is not exhaustive. It will be apparent to those skilled in the art that other formats of encoded data than those illustrated and described in FIG. 3 may be transmitted as encoded data 320. In particular, note that the data rate required for the data in coded data portion 320 is typically lower than the data rate required for uncoded video data 315. Therefore, coded data 320 can be transmitted at a very slow rate. Transmitting at these very modest bit rates allows for much less complex decoding to be used than when transmitting at uncoded video data rates.

FIG. 4 shows a transmitter 400t located within the graphics controller. Transmitter 400 is connected = V link 1
22, which is applied to a receiver within the user terminal. Transmitter 400 includes a parallel-serial shift register 410. Parallel-serial shift register 410 has a number of data and control inputs. For data input, vertical synchronization 411, keyboard data 41
Each of these data inputs, including tone data 413, audio data 414, synchronization code 415, and test data 416, is illustrated as a single line; It should be understood that bits of Parallel-serial shift register 410 is controlled by load signal 417 and shift signal 41B from timing and control logic 420. The output of parallel-serial shift register 410 is serial data 431.

Timing and control logic 420 performs the primary control functions within transmitter 400. Timing and control logic 420 includes clock input 421 and horizontal synchronization input 42
Receive 2. Timing and control logic 420 thereby generates various signals at the necessary times to other elements of the transmitter. Timing and control logic 420 provides load signal 4 to parallel-serial shift register 410.
17 and a shift signal 41B. Load signal 41
7 is added when parallel-serial shift register 410 is loaded with different data bits. shift signal 418
does not allow the shift register 410 to receive any more data input, and transfers its contents to the Manchester encoder 430 as serial data 431.
transfer to.

Manchester encoder 430 receives serial data 431 from shift register 410 and also receives a clock signal 432 from timing and control logic 420. Clock signal 432 has a different frequency than clock signal 421 that is applied to timing and control logic 420. Manchester encoder 430 generates the encoded data by exclusive ORing serial data 431 and clock signal 432. This encoded data 441 generating 441 is applied to multiplexer 440.

Multiplexer 440 serves to combine multiple signals under the control of timing and control logic 420. Multiplexer 440 receives coded data 441 from Manchester Any/430. coded video signal 44
2 is also received.

Multiplexer 440 receives square wave signal 443 and control signal 444 from timing and control logic 420 . Multiplexer 440 operates according to control signal 444 to output coded data 441 and video data 44.
2) or square wave signal) to the electrical output 44.
Send to 5.

During normal horizontal scanning, video data 442 is coupled to electrical output 445. During the horizontal retrace interval, encoded data 441 is applied to electrical output 445.

During the horizontal blanking period of one set of scanning wheels corresponding to the vertical blanking line,
A square wave 443 is coupled to multiplexer 440 and sent to electrical output 445 in place of video data 442 . In this manner, multiplexer 440 performs the assembly and combination of signals shown in FIG. Timing and control logic 42Ll sends appropriate signals on control lines 444 to cause multiplexer 440 to perform its functions.

Fiber optic transmitter 450 converts electrical signals to optical signals. The preferred embodiment of the invention uses fiber optics for the communication link 122 between the graphics controller 120 and the user terminal 130. Fiber optic transmitter 4
50 receives electrical output 445 from multiplexer 440. The fiber optic transmitter 450 has this 'electrical output 44'.
5 to a light output of 451. This optical output 451 is applied to an optical fiber (not shown) that constitutes the communication link 122.

A receiver 500 is illustrated in FIG. Receiver 500 is provided within user terminal 130 and communicates with communication link 122.
Receive input from This human power is applied as optical input 511 to fiber optic receiver 510 . Receiver 500 generates output for use by the user terminal, as will be explained in more detail below.

Fiber optic receiver 510 operates as an input to receiver 500. Fiber optic receiver 510 receives optical input 511 from communication link 122 .

The optical fiber receiver 510 converts this optical input into electrical power 51.
2 and add it to both Video Date 515 and Manchester Decoder 5200.

6, optical input 511 includes a portion of square wave signal 335 corresponding to uncoded video data 315 and a portion corresponding to coded data 320.
including. To separate these respective components,
A video date 515 and a Manchester decoder 520 are used.

Electrical power 512 is applied to Manchester decoder 520. Manchester decoder 520 is configured to recover the clock signal from the Manchester Ennie data.

When this clock signal is recovered, it becomes possible to separate the coded data from the coded video data. Manchester decoder 520 then generates clock signal 521 and data signal 522.

A synchronous pattern detector 52 where a clock signal 521 and a data signal 522 are applied to a synchronous pattern detector 525.
5 checks and determines whether the synchronization pattern 321 has been received. When synchronization pattern 321 is received, synchronization signal 526 is generated. Sync pattern 32
The reception of 1 is the most important one. This is because it marks the end of uncoded data 315 or square wave signal 335 and the beginning of coded data 320. This is clearly an important time, and synchronization signal 526 signals detection reception of synchronization pattern 321.

The main timing and control functions in receiver 500 are performed by event counter 530. Event counter 530 operates in conjunction with window 531, phase-locked loop oscillator 532, and reset select date 533 to generate appropriate timing and control signals at the output of receiver 500. event counter 530
counts the pulses it receives from phase-locked loop oscillator 532. According to this count, event counter 530 generates signals at its output, such as a date signal 534, a synchronization signal 535, a validity signal 536, a P-) signal 537, and a reset signal 538.

The phase-locked loop oscillator 532 is connected to the event counter 5
The timing pulse t used in t-30 is generated to control a number of events within receiver 500. Phase locked loop oscillator 532 is controlled by window date 531.

Window date 531 receives synchronization signal 526 from synchronization pattern detector 525 and date signal 534 from event counter 530. Window 531 applies a rate signal to phase-locked loop oscillator 532 to control its frequency, and thereby also controls event counter 532.
30 timing signals are controlled. This rate signal is governed by the rate at which synchronization signal 526 is received by synchronization pattern detector 525. Date signal 534 is used to prevent false rate signals caused by falsely detecting signal patterns. Event counter 530 generates a date signal 534 to enable window date 531 for a predetermined period of time near the expected arrival time of the synchronization pattern, and thus for the required period of the synchronization signal. Date signal 534 is preferably of variable duration, depending on the quality of the phase synchronization of synchronization pattern 3210. In other words, when the window date 531 cannot achieve good phase synchronization,
It is enabled to operate for a longer period of time under the control of the date signal. On the other hand, if the quality of phase synchronization is improved,
window) 531 is enabled for a short period of time. In this manner, the timing of events from event counter 530 is in phase with the reception of synchronization pattern 321 by communication link 122.

The event counter count is reset by reset selection date 533. Reset selection date 5
33 causes the event counter to be reset by two situations. Normally t'4 event counter 53
The reset signal from 0 occurs almost simultaneously with the synchronization signal 526. In this case, reset selection date 533 resets event counter 530 when it receives reset signal 53B. This prevents slight jitter in the reception and detection of synchronization pattern 321 from interfering with normal operation. Reset signal 53B and synchronization signal 52
If 6 and 6 move apart in time by more than a predetermined limit and this state continues for several cycles, reset selection gate 533 receives synchronization signal 526 and switches to 9 o'clock operation. If this condition continues and the reset signal 538 and synchronization signal 526 are again received within predetermined limits, normal operation is resumed. This is the reset signal 53
8 behaves differently than the synchronization signal 526, preventing false triggers from continuing.

When event counter 530 is properly set to synchronize to the reception of synchronization pattern 321, event counter 530 properly controls the output of receiver 500.

Event counter 530 generates a date signal 537 and adds it to video date 515. This causes video date 515 to pass electrical power 512 to video output 513. This date signal 537 is applied during the reception of uncoded video data 315. The time at which video 'F'-) 515 opens is set to coincide with the period during which uncoded video data 315 is received.
The time is kept consistent with the internal count of counter 530. Therefore, the video output 513 has encoded data 32
It includes consecutive scan lines of uncoded video data 315 with zeros removed. During the vertical retrace period, video date 515
is closed, so neither square wave signal 335 nor coded data 320 appears on video output 513.

Data multiplexer 540 also routes data signals to Manchester decoder 520 and event counter 53.
0 to valid data signal 536t-receive. The decoder signal 522 from the Manchester decoder 520 is a stream of serial bits that is input to the decoder during the load period.
Demultiplexer 540 is added. When receiving valid data signals from event counter 530, data demultiplexer 540 generates parallel outputs to many portions of user terminal 130. These outputs include keyboard output 541, signal tone output 542) audio output 543, and test output 544. These multi-bit data signals are utilized in a conventional manner in many parts of the user terminal equipment. When valid data signal 536 is not received from event counter 530, data demultiplexer 540 does not generate these various output signals.

Horizontal sync generator 550 and vertical sync generator 555 generate sync signals for the video portion of user terminal 130 to control horizontal and vertical scanning operations. Both horizontal sync generator 550 and vertical sync generator 555 also receive a sync signal 535 from event counter 530 .

This synchronization signal 535 is not received directly from the synchronization pattern detector 525, but from the event counter 530, which reduces the chance of false synchronization detection. Event counter 530 with window date 531 and phase-locked loop oscillator 532 provides a reliable reception indication of synchronization pattern 321 with fewer false indications than when receiving directly from synchronization pattern detector 525. Horizontal sync generator 550 generates horizontal sync signal 5 directly from sync signal 535.
51 is generated.

Meanwhile, vertical sync generator 555 also receives additional inputs.

This additional input is the vertical synchronization signal 545. Note that the vertical synchronization signal 322 is part of coded data 32001. In order to detect a valid vertical synchronization signal, a frame reset is caused in the video display of the user terminal 130, and the synchronization pattern 321 and the vertical synchronization 3
It is necessary to receive both. Vertical sync 32
2 is part of coded data 320, data signal 522 is applied to data demultiplexer 540. The generation of both synchronization signal 535 and vertical synchronization signal 545 causes vertical synchronization generator 555 to generate a social reset signal 556. This vertical reset signal 556 is used in the video display terminal to reset the video frame.

FIG. 6 shows a transmitter 600 located within the user terminal device 130. The transmitter 600 is the user terminal device 130
, transmits keyboard, mouse, and audio data to graphics controller 2120 via communication link 126 .

Input data to transmitter 600 is applied to parallel-serial shift register 610. The input data includes keyza
Data 611, mouse data 612 and audio data 6
Contains 13. As previously discussed with respect to FIG. 4, each of these input data preferably includes a plurality of parallel bits. This data is loaded into parallel-serial shift register tli10 by load instruction 614 from timing and control logic 620. shift signal 6
Upon receiving 15t-, parallel-serial shift register 610 applies serial Cheetaro 31 to Manchester encoder 630.

Timing and control logic 620 performs the primary timing and control functions of transmitter 600. Timing and control logic 620 receives clock signal 621t from receiver 500. This clock number 621 is
Associated with clock signal 521 generated by Manchester decoder 5200. With such a device, the transmitter 6
00 is coupled to the same Manchester clock signal as transmitter 400 within graphics controller 120.

Timing and control logic 620 includes load signal 61
4 and a shift signal 615 are generated in time to cause the parallel-to-serial shift register 610 to convert the input data from parallel to serial. Timing and control logic 620 includes:
It also generates a clock signal 632 and applies it to the Manchester encoder 63G. Manchester Ennie/6
30 performs a t-OR combination with data 631 and clock 632 to generate coded data 641.

The timing and control logic also generates a control signal 642 and applies it to the synchronization signal adder 640. The synchronous 4N booster 640 receives coded data 641t from the Manchester encoder 631', and receives the coded data 320
A synchronization signal similar to the synchronization pattern 321 of is added to the coded data 641. The time this synchronization signal is applied is
Controlled by control signal 642. Synchronous signal adder 6
40 thus produces an electrical output 645.

Fiber optic transmitter 650 receives electrical output 645. Fiber optic transmitter 650 produces an optical output 651 that corresponds to electrical output 645. This optical output 651 is applied to an optical fiber (not shown) that constitutes the communication link 126. In this manner, keyboard/mouse and audio data is added to communication link 126.

FIG. 7 shows a receiver 700 located within graphics controller 120. Receiver 700 is connected to communication link 126 to receive the transmitter 600 transmit ratio signal.

Receiver T00 includes a fiber optic receiver 710 that receives optical input 111. This optical fiber constitutes a communication link 126. With the received light input cuff 11, the fiber optic receiver 710 generates an electrical input /12t-.

Electric man cuff 12 is added to Manchester decoder 720. As I mentioned earlier about the Manchester Decoder 520, and to my colleagues, the Manchester Deco/720 is used in the Manchester Encoder 630 and clocks 632.
A clock signal 721 and a data signal 722 are generated that match the . This data signal 722 corresponds to the original data received by transmitter 600.

Clock signal 721 and data signal 722 are applied to serial-parallel shift register 730. The parallel outputs of series-parallel shift reso-stuff 30 are applied to output latch 740.

Output latch 740 also receives a latch clock signal from synchronous detector 725. When the synchronous detector 725 receives the electric cuff 12 and detects a proper synchronous signal, it generates the latch clock 16. This synchronization signal is a synchronization signal added to the coded data by the synchronization booster 640. Synchronous detector 125 signals this detection by launch clock 726. At this time, is the data loaded into the output latch 740 valid?
Motsu. Therefore, the output latch 740 produces keyboard data 741, mouse data 742, and audio data 743 corresponding to the input data of the transmitter 600. This data is used by graphics controller 120 and central processing unit 110. These signals from user terminal 130 are used to control the operation of the data processing equipment.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a diagram showing a general outline of a combination of a data processing device and a user terminal device to which the present invention is applied, and FIG. 2 is a diagram showing a transmitter according to a preferred embodiment of the present invention. FIG. 3 shows the format of data transmitted from the data processing device to the user terminal device according to a preferred embodiment of the present invention. FIG. 4 is a diagram of a preferred embodiment of a transmitter arranged in a data processing device according to the invention; FIG. 5 is a diagram of a preferred embodiment of a receiver in a user terminal; FIG. FIG. 7 is a diagram of a preferred embodiment of a transmitter in a user terminal, and FIG. 7 is a diagram of a preferred embodiment of a receiver in a data processing device. (Explanation of symbols) 100... Computer device 1
10... Central processing unit 112.
116.122.126...Communication link 120...
...-- Graphic controller 130
・−・・・−・ User terminal device 210.2
40.400.600...Transmitter 220.230.5
00, Too...Receiver 410.61G...
Low-cost serial shift register 420.62υ --- Timing and control logic 430.630 ---
Manchester encoder 440...
Multiplexer 450.650...- Source fiber transmitter 510.710...-Optical fiber receiver 51
5... Video date 520.72
0...Manchester decoder 525...
... Synchronization pattern detector 530 - ...
Event counter 531...
Window date 532... Phase locked loop oscillator 53
3... Reset selection date 540...
・・・−・ Data demultiplexer 550・−
...Horizontal synchronization generator 555...
Vertical synchronization generator 640 --- Synchronization signal adder 725 --- Synchronization detector

Claims (10)

[Claims] (1) A communication interface for a video display device, comprising: (a) a communication link for transmitting a communication signal; and (b) a video display generation device, which: (1) generates a digital video signal having a plurality of video scan lines. a video data encoder; 2) a control data encoder that generates a digital control signal including self-clocking control data having a slower data rate than the digital video signal; 3) the video data encoder and the control data encoder; connected to an encoder to generate and multiplex the digital control signal during the retrace period of the digital video signal by time-division multiplexing the digital video signal and the digital control signal; a multiplexing device for forming a signal; and 4) a transmitting device connected to the communication link and the multiplexing device to generate a communication signal on the communication link in response to the multiplex signal. c) a video display device comprising: 1) a receiving device connected to the communication link to receive the communication signal; 2) a receiving device connected to the receiving device to transmit the communication signal to the digital video signal and self-clocking detection; a demultiplexing device comprising means for demultiplexing said digital control signal to enable detection of said control data by detecting a self clock of said digital control data; and said self clocking detection. 3) a time gating device connected to the demultiplexing device to enable operation of the self-clocking detection device only during time intervals in which a retrace period is expected; 4) a utilization device connected to the demultiplexing device to receive and utilize the digital control data; A communication interface for the video display device as described above. (2) In claim 1, the control data encoder further includes a device for generating a predetermined synchronization bit pattern indicating the end of a video scan line of the digital video signal; A communication interface for a video display device, comprising: a synchronization bit pattern detection device for detecting reception of a predetermined synchronization bit pattern; and a horizontal reset device for starting display of a new video line upon detecting said synchronization bit pattern. (3) In claim 1, the control data encoder also includes a device for generating a predetermined vertical synchronization bit pattern indicating the end of a video frame of the digital video signal, and the utilizing device a video display device, comprising a vertical synchronization bit pattern detection device for detecting reception of the predetermined vertical synchronization bit pattern and a vertical reset device for starting displaying a new video frame when detecting a previous vertical synchronization bit pattern. communication interface for (4) In claim 1, the digital control data includes signal sound generation data;
Further, the communication interface for a video display device, wherein the utilization device includes a signal sound generation device that generates a signal sound in response to the signal sound generation data. (5) In claim 1, the digital control data includes synthetic speech generation data, and the utilization device includes a synthetic speech generator that generates synthetic speech in response to the synthetic speech generation data. A communication interface for a video display device, comprising: a communication interface for a video display device. (6) In claim 1, the communication link includes an optical fiber cable, and the transmitting device includes an optical fiber cable connected to the optical fiber cable.
a fiber optic transmitting device that generates a digital optical signal corresponding to a multiplexed signal, and the receiving device includes a fiber optic transmitting device that generates a digital optical signal corresponding to a multiplexed signal; A communication interface for a video display device, including a fiber optic receiver that generates a demodulated signal in response to an optical signal. (7) In claim 1, the communication link includes an optical fiber cable including a first optical fiber and a second optical fiber, and the transmission device is connected to the first optical fiber and the multiplex a first optical fiber transmitting device for generating a digital optical signal corresponding to a signal, the first optical fiber transmitting device being connected to the second optical fiber and responsive to the optical signal transmitted by the second optical fiber to the video display generating device; a first optical fiber receiver that generates an output signal, and an output device that is connected to the first optical fiber receiver and utilizes the output signal; a second fiber optic receiver for generating a demodulated signal responsive to the digital optical signal transmitted by the optical fiber; and a second optical fiber transmitter connected to the input device and the second optical fiber to generate a digital optical signal corresponding to the input signal on the second optical fiber. , Communication interface for video display devices. (8) In claim 7, the input device includes a manual keyboard; Communication interface for video display devices. (9) In claim 7, the input device includes a manual instruction device; Communication interface for video display devices. (10) The communication interface for a video display device according to claim 7, wherein the input device includes an audio encoding device operable by audio.