DE4411876A1 - Video interface system and method - Google Patents

Abstract

This invention is intended to make the switching device under the video interface system superfluous. This receives the video signal from a large number of host computers in a hard copy device, and prints out the image. The adapters which are assigned to each host computer are in each case arranged with the individual host computers, which produces the priority chain connection between the adapters. The invention can also be used for remote transmission of video data. The invention can also control two or more sets of hard copy devices in the same priority chain. In this video interface system, the adapter is equipped with the A/D converter, the synchronous isolating circuit, the adapter number setting switch and the serial communication circuit, and the hard copy device is equipped with the graphic memory, the phase-locked loop (PLL), the serial communication circuit, the priority setting circuit and the control circuit.

Description

The present invention relates to an interface system and a method for interfacing between one Printer for images and / or characters that are on a type pointing device such. B. a cathode ray tube and one Color hardcopy device are output, and a host computer, which a video signal to the color hardcopy device or that Display device outputs.

If a number of host computers are connected to a hardcopy device Sen is to be including a switching device a relay used to output a video signal from the master switch computer. And even if the host computer is on the same or more than two hardcopy devices is connected uses a switching device with which the video signal is switched.

This type of switching device could only be used with a coaxial cables, etc. for the purpose of direct transmission of video signals on the recording device such. B. a color hard copy machine operated. But since more and more high frequency  too high for the video signals with increasing tendency solving image transmission is used, it always will more difficult to get video signals over relatively long distances without Transmit deterioration of the high frequency video signal also with the use of a coaxial cable; another disadvantage when using such a coaxial cable is that Cable is very large.

The object of the present invention is to make a video cut point system and a method for remote transmission of Video signals without degradation of the video signals, too for high-frequency video operation and for the transmission of Image data on recording devices such as B. a color hard copy device without providing the above switching device.

To solve the above tasks, this includes fiction appropriate video interface system: a host computer that does the Outputs video signal for image display, an adapter that the Video signal processed and the synchronization signal and outputs the image data and attached to a priority chain is closed, to which the control signals are sent and from it are received, and a recorder that syn chronization signal and records the image data and that Sends control signals to the adapter and receives them; and which is controllable in its switching function, the priori chain is designed so that means of communication in Adapters or in the recording device are provided. The above Adapter is equipped with an A / D converter, with which the Signal in the form of a digital signal to the recording device can be transmitted in such a way that it is the radio frequency Video signal without deterioration over a proportionate can transmit long distance. The sending also takes place and receiving the signal between the adapter and the on device between a differential driver and a Differential receiver. In cases where a plurality of Recording equipment is used is a priority setting set up the priority order in each of the  Recording devices. Due to the above means, e.g. B. for two sets of recorders included in the system each of the cradles is with a DIP switch equipped, depending on the setting ent decides whether the recording device is device A or device B. should, and with a control circuit depending on the setting connects a bus to device A or device B.

Converts in the video interface system of the above configuration from a command signal issued by the recording system is given, the selected adapter is output by the host computer level image signal from the analog data into digital data and transfers them to the priority chain. Because the initial state the other, not selected adapter, to the priority chain is controlled so that it has a high impedance, only the signals given by the selected adapter transferred to the receiving device.

The total length of the priority chain may be due to the better Performance of noise reduction characteristics extended be because the above signal is converted into a digital signal was changed and because the signal transmission and reception each terminal is at a different level. The means that the picture will not be lost even with remote transmission worsened. In the case of a variety of intake devices tungen, z. B. in video interface systems with two sentences of recording devices, the recording device works set as device B with the priority setting means (the recording device, the second in the recording sequence Has priority) so that device A (the device that is in the Consequence the first priority has) receiving the priority chain allows. So if a cradle first If priority is selected for printing, the image data will be displayed transferred this device and if the device is the first Priority was not selected for printing and the up second priority device was selected for printing,  the image data to the recording device of the second Transfer priority.

The video interface method in video interfaces system that with the host computer, with the adapter and with the Is equipped, is set up for this purpose

• (a) the signal including the signal that the desired adapter for the priority chain of the adapters of the ge chose cradle dials to issue,
• (b) the synchronization signal (SYNC signal) to the adapter output, which is selected by the above signal, and the Output terminals for the SYNC signal and the image data of the other adapter that is not selected by the signal above, to set high impedance
• (c) to cause the selected cradle outputs the sampling clock signals with the SYNC signal that are issued by the adapter that is from the priority chain selected above,
• (d) to cause the selected adapter to display the image data, that represent the digital image signal, along with the Ab outputs key clock signal to the above priority chain,
• (e) to cause the selected cradle stores the image data in a storage means.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a block diagram of the video interface circuit according to the invention.

Fig. 2 shows a circuit diagram for the connection of the control computer, the adapter and the hard copy devices which relate to the video interface system according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Fig. 1 shows the block diagram of an embodiment which refers to the inventive interface system. In this figure, the video signal, which contains the SYNC signal, is sent to the adapter 31 by the host computer, which is not shown here and which outputs the video signal. In the event that the video signal is equal to the "Sync on green" signal form, the SYNC signal separation circuit 1 in the adapter 31 will separate the SYNC signal from the video signal, and the separated signal will be sent to the PLL (phase locked) via the multi-wire cable 10 Loop - phase-synchronized loop) 2 in the hardcopy device 21 . And if the video signal is the "Separate Sync" waveform, the SYNC signal separation circuit 1 transmits the signal and transmits it over the multi-wire cable 10 as it is to the hardcopy device 21 because the SYNC signal has already been separated. PLL 2 generates the sampling clock, which is phase-synchronized with the input SYNC signal. This sampling clock is transmitted to the adapter 31 via the multi-core cable 10 . The A / D converter 3 in the adapter 31 carries out the A / D conversion of the video signal via this sampling clock and transmits the digitized image data via the multi-wire cable 10 to the hardcopy device 21 . The hard copy device stores the transmitted image data in the graphic memory 4 which is present in the hard copy device 21 .

The adapter number setting switch 5 in the adapter 31 sets its adapter number. If several adapters are installed, a different adapter number must be set. A mechanical part, such as. B. a DIP switch, or a memory element in which can be written from the outside, such as. B. a RAM, NVRAM or EEPROM, can be used as this adapter number switch 5 . The signal communication circuit 6 in the adapter 31 and the serial communication circuit 7 in the hard copy device 21 control the mutual relationships between the adapter 31 and the hard copy device 21 via the multi-wire cable 10 , and the serial communication circuits 6 and 7 are controlled by the CPUs are not shown in the figure and are built into the adapter 31 or hardcopy device 21 . When the command including an adapter number is sent from the hardcopy device 21 to the adapter 31 , the serial communication control acts through the serial communication circuits 6 and 7 , so that the adapter 31 whose number matches the adapter number sends the response command. Accordingly, the multiple adapter sets and one or more hard copy devices are controlled in a mutual relationship.

The A / B setting switch 8 in the hard copy device 21 is the priority setting means for the multiple settings of the ready-to-use hard copy device. In this embodiment, the case of two sets of a ready-to-use hardcopy device is shown, with the A / B setting switch, the one set "A" is set to a higher priority.

For this A / B setting switch 8 , the Adapterein setting switch 5 can now be used as a mechanical part, such as, for. B. a DIP switch, or a memory element to which can be written from the outside, such as. B. a RAM, NVRAM or EEPROM can be used. The position of the switch, which is set by the A / B setting switch 8 , that is, the priority order of the hard copy machine, is given to the A / B control circuit 9 in the hard copy machine 21 . The hard copy machine set to "B" by the A / B set switch 8 , that is, the one set to the second or lower priority (hereinafter referred to as hard copy machine B, while the other one set by the A / B set switch 8) "A" (that is, the priority whose priority has been set, hereinafter referred to as hard copy device A) gives the request signal B-RQ to the hard copy device A, and can pick up a bus of the video-related signal that data the picture, the SYNC -Signal and the sampling clock, as well as the serial connecting lines that send and receive the command signal with the adapter only in the event that an acknowledgment signal B-ACK is sent back from the hardcopy device A. The A / B control circuit 9 is connected to the CPU which is used in the hardcopy device 21 , although it is not shown here. And all the A / B control circuits in the hard copy device A and in the hard copy device B are connected to one another via the multi-core cable 10 . Since the signal line carrying the request signal B-RQ and the acknowledgment signal B-ACK is contained in the multi-core cable 10 , these signals are also transmitted to the adapter 31 , although they have no effect on the adapter 31 . As explained above, the A / B control circuit in the hard copy machine B controls the transmission of a B-RQ signal and the reception of a B-ACK signal, and the A / B control circuit in the hard copy machine A controls the reception of the B-RQ signal and the like Send the B-ACK signal.

The input and output terminals of both the adapter 31 and the hard copy device 21 are ver bindable with the priority chain. That is, in the adapter 31 , the input or output signals such as the output of the image data, the input of the sampling clock, the SYNC signal output, the serial communication signal TX and RX and the B-RQ and B-ACK based on the serial communication signal controlled by the hard copy device 21 , and in the event that the specific adapter is not selected, all terminals except the input and output terminals of the serial communication circuit are at high impedance. The higher-level adapter and the downstream adapter (s) are thus constituted such that they can be connected to the priority chain. And although on the one hand the gate circuits which control the position thereof are set to the active, ie high-lying impedance state at the input and output terminals, the gate circuits are not shown in the figure. On the other hand, the input signals such as the image data input, the SYNC signal input and the serial communication signal RX can always be received in the hardcopy device, but the output signals such as e.g. B. the sampling clock and the serial communication signal TX are given on the bus of the priority chain via the gate circuits, which are not shown here and which are controlled by the output signal of the A / B control circuit 9 . The superordinate and the subordinate hardcopy circuit can thus be connected in priority to the priority chain. Gate circuits are used here which are conventionally used for the priority chain.

As a driver for each output signal, the differential driver is used, which works on the bus of the priority chain and outputs the TTL level signal in the adapter 31 , and the hard copy signal 21 is converted into the differential level signal. As the receiver for each input signal, the differential receiver is used, which converts the differential level signal that is input into the adapter 31 and sets the hardcopy device 21 to the TTL level signal. As mentioned above, the noise reduction characteristic is improved and stable signal transmission can be realized by means of the means that the signals which are given to and received by the individual devices are converted to the differential level one.

Fig. 2 shows the connection of the video interface system into which n sets of host computers, n sets of adapters, each of which is connected to one of the above host computers, and 2 sets of hard copy devices are constituted.

The hard copy device-A, in which the graphics memory 4 , the PLL 2 , the serial communication circuit 7 , the A / B control circuit 9 and the A / B setting switch 8 in FIG. 1 are constituted, is the device with privileged priority according to the A / B setting switch 8 . And the hard copy device-B, in which the graphics memory 4 , the PLL 2 , the serial communication circuit 7 , the A / B control circuit 9 and the A / B setting switch 8 are constituted as in the hard copy device-A, is in order of priority the A / B setting switch 8 . The hardcopy device A and the hard copy device-B are connected to each other via the multicore cable 11 X.

Hardcopy device A and hardcopy device B need not be the same in print mode, e.g. For example, one may be a sublimation type thermal ink transfer printer and the other may be a fusion type thermal ink transfer printer. Furthermore, the one hard copy machine may be an electrophotographic type printer and the other may be a thermal ink transfer printer. And both can be of the same type, and in this way one printer can be used as a replacement for the other, ie the second steps in immediately if the main printer fails, runs out of paper, and so on. In short, the video interface only has to agree with how it was constituted with the graphics memory 4 , the PLL 2 , the serial communication circuit 7 , the A / B control circuit 9 and the A / B A setting switch 8 , etc.

The adapter-a 31 has the A / D converter 3 , the sync signal separation circuit 1 , the serial communication circuit 6 , the adapter number setting switch 5 in the configuration as shown in FIG. 1, and is via the video signal cable 12 a connected to the host computer-a 41 and via the connecting cable 11 a to the hardcopy device-A 21 . The adapter number setting switch of adapter-a 31 is set to "1". Both the adapter-b 32 and the adapter-n 33 have the same configuration as the adapter-a 31 . The adapter-b 32 is connected via the connecting cable 11 b to the adapter-a 31 , and via the connecting cable 11 c to the adapter-c (not shown), and in the same way to others in running order, and last is the Adapter-n 33 connected via the connecting cable 11 n to the adapter (not shown) (n-1); the daisy chain connector organizes all of these connectors including the two sets of hard copy devices. The adapter number setting switch of the adapter-b 32 is set to "2", the adapter number setting switch of the adapter-c to "3", and in cases where the system comprises five sets of host computers and five sets of adapters, the Adapter number setting switch of adapter-n 33 set to "5".

Operation of the video interface system in one The above configuration is explained here below.

As a rule, two sets of hard copy devices poll the adapters cyclically. That is, the hard copy machine-A 21 sends the command signal including the adapter number "1" to the priority chain circuit via the serial communication circuit. If the operator of the host computer-a 41 does not want a hard copy on paper, the hardcopy device-A 21 sends the command signal with its adapter number "2" to the priority chaining circuit via the serial communication circuit, because the adapter-a 31 does not resend the response signal the hardcopy device-A 21 sends back. If the operator of host computer device-b 42 does not want a sheet of hard copy, hard copy device-A 21 sends the command signal with adapter number "3" via the communication circuit to the priority daisy-chain circuit because adapter-b 32 does not return the response signal to the hard sends back copygerät-A 21 . In this way, the command signal with the sequentially changed adapter number is sent to the priority chain circuit via the serial communication circuit. If there is then no response signal from adapter-n 33 , hardcopy device B 22 repeats the same process in the same order as above. If the hard copy device-B 22 cannot receive the response signal, the hard copy device-A 21 repeats the same procedure again.

The case will now be explained that the operator of the host computer-b 42 wants to print out a sheet of a hard copy. The operator has to select the desired hardcopy device via the simple control panel which is connected to the master computer-b 42 to the adapter-b 32 . In this case we want to assume that he selected the hard copy device B 22 . When the hard copy machine-B 22 makes its call and sends the command signal with the adapter number "2" to the priority chaining circuit, the adapter-b 32 gives the response signal to the priority chaining circuit via the serial communication circuit. Upon receipt of the above response signal, hardcopy device-B 22 sends the request signal B-RQ to the daisy chain, which means the bus request to hardcopy device-A 21 . The hard copy device A 21 gives the acknowledgment signal B-ACK to the priority chaining circuit, while the hard copy device A 21 does not have to address the bus. Then the hardcopy device B 22 can take over the bus.

The selected adapter-b 32 sets the output terminal to the connecting cable 11 to "active". Upon receipt of the SYNC signal from the sync signal separation circuit from the video signal input from the host computer-a 41 via the video signal cable 12 a, there is the adapter-b 32 to the sync signal line, which is contained in the connection cable 11 . At this moment there is the status of high impedance, apart from the serial communication circuit, the output terminals to the connecting cable 11 of the adapter, which is not selected, apart from the adapter-b 32 , do not interfere with the transmission of the SYNC signal that the selected adapter -b outputs 32 because the output terminals, apart from one for the serial communication circuit, are in high impedance state. Upon receipt of the SYNC signal from adapter-n 32 to the internal PLL, and generation of the sampling clock phase-synchronized with the SYNC signal, there is the hard copy device B 22 in the sampling clock line in the connecting cable 11 . This above sampling clock is only picked up by adapter-b 32 and is used as the sampling signal for which the A / D converter of adapter-b 32 converts the video signal from A to D. The A / D converter of the adapter-b 32 converts the video signal from A to D and outputs it to the image data line in the cable 11 , whereby image data is obtained as a result of the above conversion. The hard copy device B 22 temporarily stores this image data in the graphics memory, and the stored data is read later and on the image medium, e.g. As paper, printed out in the printout part, which is not shown in the figure. As above, the hard copy can be obtained, which shows the same image as the display device, which, for. B. is a cathode ray tube of the host computer.

Although in the above embodiment two sets of hard copy devices are used, does not have to be particularly pointed out that the invention is also available for three or more hard copies devices can be executed. With three or more Of course, the switch must be converted to hardcopy devices be an A / B priority setting for three or can set more devices, and also the A / B tax circuit must be designed so that a bus request arbitrarily chosen from three or more devices can be.

To apply the invention to the case of a hard copy device set To be able to turn does not need to be stressed that the priority chaining of the hardcopy device has just been completed needs to be and that the priority chain of the Last priority adapter or hardcopy device must be closed.

As explained above, this invention can Video signal from a large number of host computers without switching direction given to the recording device or device and the image is not adversely affected quality, and remote transmission can also be realized be because the video signal from the adapter into a digital image signal is converted and receiver and transmitter from Differential type can be used. Furthermore, the cables can be thin and the system environment to be intelligent because no coaxial cable for connecting the adapter and the recording device is needed. And further, because more than two sentences Recording devices can also be controlled two or more sets on the same priority chain operate connection. Accordingly, and even in such Cases where different printouts for different  Liche use are required, the present Er useful because both an inkjet device from High quality sublimation type as well a very fast, however, cheap type of function can be easily controlled.

Claims (6)

1. An adapter for inputting a video signal from a host computer device and for outputting a video data corresponding to the video signal to a recording device, at least including:
a synchronizing signal separating means for separating a synchronizing signal from the video signal and for transmitting the video signal to the recording apparatus; and
an A / D converter for analog / digital conversion of the video signal by a sampling clock, which is obtained from this synchronizing signal, and for outputting a digital image data. 2. An adapter according to claim 1, further comprising:
An adapter number setting means for setting a specific adapter number for a plurality of adapters, respectively; and
an adapter-side communication means for receiving a command signal containing this adapter number, which is sent from the recorder, and for sending back a response command signal when the adapter number set by the adapter number setting means is identical to the adapter number contained in the command signal. 3. A recording device for forming an image on a recording medium based on the image data output by an adapter, comprising at least:
storage means for storing the image data; and
a PLL circuit for outputting a sampling clock signal which is in phase synchronization with a received signal. 4. A recording device according to claim 3, further comprising:
Priority order setting means for setting the priority order by which it is determined whether the recording apparatus has a higher or a lower priority;
recording device side communication means for sending a command signal having an adapter number and capable of receiving a response command signal from the adapter; and
control means for controlling the transmission of the command signal containing the adapter number from the recording device side communication means depending on a value set by the priority order determining means and an operation status of the other recording devices. 5. A video interface system that includes:
at least one or more master computer devices for outputting a signal which includes a video signal for outputting an image on an image display device;
an adapter that includes a synchronizing signal separating device for receiving a video signal, separating a synchronizing signal from the video signal and outputting the synchronizing signal, an A / D converter for A / D converting the video signal by a sampling clock consisting of the synchronizing signal) and outputting a digital image data, an adapter number setting device for setting a specific adapter number, and an adapter-side communication means for receiving a command signal including an adapter number and returning a response command signal when the adapter number set by the adapter number setting means is identical to the adapter number, which is contained in the command signal, in which a number of adapters corresponds to a number of host computers and the adapters are connected to the host computer devices via a priority chain connection; and
a recording device which includes: storage means for storing the digital image data, a PLL circuit for outputting the sampling clock which is phase-synchronized with the synchronous signal, priority-following means for determining the priority which decides which recording device has a higher priority, a recording device-side Communication means for sending the command signal containing the adapter number and receiving the response command signal, and control means for controlling the sending of the command signal including the adapter number from the recording device side communication means depending on a value set by the priority order setting means, and an operating status of the other recording devices. 6. A method of operating a video interface system which includes: a host computer device for outputting an image signal for displaying an image, an adapter for outputting a synchronous signal and image data, and for transmitting and receiving a control signal in which the adapters are connected in a priority chain and a recording device for receiving the synchronizing signal and the image data and for sending and receiving control signals to and from the adapter, this method comprising the following steps:

• (a) output of a signal which contains a signal for designating a desired adapter from a selected recording device to a priority chain of the adapters,
• (b) outputting the synchronizing signal in an adapter selected by this signal, and setting the output terminals for the synchronizing signal and the image data to the high impedance state in an adapter not selected by the signal;
• (c) output of a sampling clock, which is synchronous with the synchronous signal, from the selected adapter from the selected recording device to the priority chain;
• (d) converting an image signal into an image signal digitized by the sampling clock in the selected adapter and outputting the image data to the priority chain; and
• (e) storing the image data in storage means in the selected recording device.