Server double-signal-source switching display output system and method

Abstract

The invention discloses a server double-signal-source switching display output system and method, mainly relates to the technical field of signal source switching, and is used for solving the problem that an existing scheme cannot meet the synchronous switching use requirement of an external signal source and a computer end signal source. And in addition, the whole process of replacing the computer end and the KVM end by the user is relatively tedious and inconvenient to operate. Comprising an external input and output module used for acquiring an external signal; the server main control module is used for outputting a server main control signal; the signal source switching module is used for converting the first display signal and the second display signal into signals in a preset format, and then a final output signal is determined between the first display signal and the second display signal; determining a final control signal between the USB equipment external control signal and the USB equipment internal control signal; and the external input and output module is connected with external equipment and is also used for sending the external output signal to the corresponding external equipment based on the format of the external output signal.

Description

Technical Field

[0001] The present application relates to the technical field of electronic products, and in particular to a server dual-signal source switching display output system and method. Background Art

[0002] KVM stands for Keyboard, Video and Mouse, which means using a set of keyboard, monitor or mouse to control multiple devices, and plays an important role in remote scheduling and monitoring.

[0003] Today, with the widespread use of laptops, there is an increasing demand for laptops with multi-function displays. Existing ordinary KVM monitors or laptops cannot simultaneously meet the requirements for synchronous switching of external signal sources and computer-side signal sources. When users need to use an external signal source or a laptop, they need to tediously switch between the computer side and the KVM side. The overall process is cumbersome and inconvenient to operate. In addition, at this stage, users who already have ordinary KVM monitors or laptops mainly use software solutions to achieve synchronous switching of signal sources. For example, some third-party software is used to help users manage multiple monitors and signal sources, and provide a user interface for switching. Such a solution requires some configuration of the system and installation of additional software.

[0004] Therefore, there is an urgent need for a server dual signal source switching display output system and method to solve the problem that the existing ordinary KVM monitors or laptops cannot meet the requirements of synchronous switching of external signal sources and computer signal sources; in addition, the overall process of users replacing the computer end and the KVM end is relatively cumbersome and inconvenient to operate. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present application provides a server dual signal source switching display output system and method to solve the problem that the existing ordinary KVM monitors or laptops cannot meet the requirements of synchronous switching of external signal sources and computer-side signal sources; in addition, the overall process of users replacing the computer side and the KVM side is relatively cumbersome and inconvenient to operate.

[0006] In the first aspect, the present application provides a server dual signal source switching display output system, the system comprising: an external input and output module, for obtaining external signals; wherein the external signals include a first display signal of a KVM signal source and an external control signal of a USB device; a server main control module, comprising an integrated graphics card and an independent graphics card, for outputting the server main control signal; wherein the server main control signal includes a second display signal, an external output signal and an internal control signal of a USB device; a signal source switching module, comprising a display switching unit, an output selection unit and a USB control switching unit, and connected to the external input and output module and the server main control module, for converting the first display signal and the second display signal into a preset format signal, and then determining the final output signal from the first display signal and the second display signal; and determining the final control signal from the external control signal of the USB device and the internal control signal of the USB device; wherein the output signals are display signals and external output signals respectively; the external input and output module, connected to the external device, is also used to send the external output signal to the corresponding external device based on the format of the external output signal.

[0007] Furthermore, the second display signal at least includes: a display DP signal, a first display HDMI signal and a USB device internal control signal; the external output signal at least includes: an external DP signal, a first external HDMI signal, and a first external VGA signal.

[0008] Furthermore, the integrated graphics card is used to output a display DP signal or an external DP signal, and the independent graphics card is used to output a first display HDMI signal, a first external HDMI signal or a first external VGA signal; wherein the USB device includes at least: a touch screen, a keyboard and a mouse.

[0009] Furthermore, the display switching unit includes a first signal converter, a second signal converter, a first signal selector, and a signal selection processor; wherein the first signal converter is connected to the integrated graphics card in the server main control module, and is used to convert the display DP signal into a second display HDMI signal; the second signal converter is connected to the integrated graphics card, and is used to convert the external DP signal into a second external HDMI signal or a second external VGA signal; the first signal selector is connected to the first signal converter and the independent graphics card in the server main control module, and is used to obtain the first display HDMI signal and the second display HDMI signal, obtain a selection instruction through a preset first selection key, and obtain a selected display HDMI signal; the signal selection processor is connected to the external input and output module and the first signal selector, and is used to obtain the selected display HDMI signal and the second display VGA signal, obtain a selection instruction through a preset second selection key, obtain a selected display signal, and convert the selected display signal into a display signal in LVDS format.

[0010] Furthermore, the display switching unit includes a display screen signal converter, and the display screen signal converter is connected to the signal selection processor and the server LCD screen; it is used to convert the display signal in LVDS format into a display signal in EDP format, and then transmit it to the server LCD screen.

[0011] Furthermore, the output selection unit includes a second signal selector and a third signal selector; the external output signal includes at least an HDMI output signal and a VGA output signal; wherein the second signal selector is connected to the independent graphics card and the second signal converter, and is used to obtain the first external HDMI signal and the second external HDMI signal, and obtain the selection instruction through the preset third selection key to convert the external HDMI signal corresponding to the selection instruction into the HDMI output signal; the third signal selector is connected to the independent graphics card and the second signal converter, and is used to obtain the first external VGA signal and the second external VGA signal, and obtain the selection instruction through the preset fourth selection key to convert the external VGA signal corresponding to the selection instruction into the VGA output signal.

[0012] Furthermore, the external device includes at least an external HDMI processing device and a VGA processing device, and the format of the external output signal includes at least an HDMI output signal and a VGA output signal; the external input and output module is used to output the HDMI output signal to the external HDMI processing device and output the VGA output signal to the external VGA processing device.

[0013] Furthermore, the USB control switching unit includes a fourth signal selector; the fourth signal selector is connected to the external input and output module and the USB device, and is used to obtain the external control signal of the USB device and the internal control signal of the USB device, and obtain the selection instruction through the preset fifth selection key to output the USB device control signal corresponding to the selection instruction as the final control signal.

[0014] Furthermore, the system also includes a button indicator light, and the button indicator light includes at least a power on indicator light, a power indicator light, a hard disk indicator light, and a current signal source indicator light; and the signal source indicator light is connected to the signal source switching module and the server main control module, and is used to obtain the control instructions issued by the signal source switching module or the server main control module.

[0015] In the second aspect, the present application provides a server dual-signal source switching display output method, which is applied to a server dual-signal source switching display output system, and the method includes: obtaining an external signal through an external input and output module; wherein the external signal includes a first display signal of a KVM signal source and an external control signal of a USB device; obtaining a server main control signal through a server main control module; wherein the server main control signal includes a second display signal, an external output signal and an internal control signal of a USB device; through a signal source switching module, converting the first display signal and the second display signal into a preset format signal, and then determining the final output signal from the first display signal and the second display signal; and determining the final control signal from the external control signal of the USB device and the internal control signal of the USB device; wherein the output signals are a display signal and an external output signal respectively; through the external input and output module, based on the format of the external output signal, sending the external output signal to the corresponding external device.

[0016] Those skilled in the art can understand that the present application has at least the following beneficial effects: The external signal is obtained through the external input and output module, the internal signal (server main control signal) is obtained through the server main control module, and then the signal is selected from the external signal and the internal signal through the signal source switching module, and the selected signal is displayed on the LCD screen (display signal), and the final control signal can be determined between the external control signal of the USB device and the internal control signal of the USB device. Based on this, it can be seen that the present application can switch between external and internal display signals and can switch between external USB control signals (USB device external control signals) and internal USB control signals (USB device internal control signals), realizing the synchronous switching use requirements of the external signal source (external signal) and the computer-side signal source (server main control signal), and the scheme involved in the present application does not need to tediously replace the computer side and the KVM side during actual use, and the entire implementation process is relatively convenient.

[0017] In addition, the present application can also select the signal to be transmitted to the outside, and then send the external output signal to the corresponding external device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Some embodiments of the present disclosure are described below with reference to the accompanying drawings, in which: Figure 1 It is a schematic diagram of the internal structure of a server dual signal source switching display output system provided in an embodiment of the present application.

[0019] Figure 2 It is a schematic diagram of the internal signal transmission process of a server dual signal source switching display output system provided in an embodiment of the present application.

[0020] Figure 3It is a flow chart of a server dual signal source switching display output method provided in an embodiment of the present application.

[0021] Description of reference numerals: 100, external input and output module; 200, server main control module; 210, integrated graphics card; 220, independent graphics card; 300, signal source switching module; 310, display switching unit; 311, first signal converter; 312, second signal converter; 313, first signal selector; 314, signal selection processor; 315, display screen signal converter; 320, output selection unit; 321, second signal selector; 322, third signal selector; 330, USB control switching unit; 331, fourth signal selector; 400, server LCD screen; 500, USB device; 510, touch screen; 520, keyboard; 530, mouse. DETAILED DESCRIPTION

[0022] It should be understood by those skilled in the art that the embodiments described below are only preferred embodiments of the present disclosure, and do not mean that the present disclosure can only be implemented through the preferred embodiments. The preferred embodiments are only used to explain the technical principles of the present disclosure, and are not used to limit the protection scope of the present disclosure. Based on the preferred embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work should still fall within the protection scope of the present disclosure.

[0023] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0024] The technical solution proposed in the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0025] Figure 1 A server dual signal source switching display output system is provided in an embodiment of the present application. Figure 1 As shown, the system provided in the embodiment of the present application mainly includes: an external input and output module 100, a server main control module 200, and a signal source switching module 300.

[0026] The external input and output module 100 is used to obtain external signals; wherein the external signals include a first display signal of a KVM signal source and an external control signal of a USB device.

[0027] The server main control module 200 includes an integrated graphics card 210 and an independent graphics card 220, which are used to output a server main control signal; wherein the server main control signal includes a second display signal, an external output signal and a USB device internal control signal.

[0028] It should be noted that the second display signal at least includes: a display DP signal, a first display HDMI signal and a USB device internal control signal; the external output signal at least includes: an external DP signal, a first external HDMI signal and a first external VGA signal.

[0029] As an example, the integrated graphics card 210 is used to output a display DP signal or an external DP signal, and the independent graphics card 220 is used to output a first display HDMI signal, a first external HDMI signal or a first external VGA signal; wherein the USB device 500 includes at least: a touch screen 510, a keyboard 520 and a mouse 530.

[0030] Among them, the signal source switching module 300 includes a display switching unit 310, an output selection unit 320 and a USB control switching unit 330, and is connected to the external input and output module 100 and the server main control module 200, and is used to convert the first display signal and the second display signal into a preset format signal, and then determine the final output signal from the first display signal and the second display signal; and determine the final control signal from the external control signal of the USB device and the internal control signal of the USB device; wherein the output signals are display signals and external output signals respectively.

[0031] It should be noted that the display switching unit 310, the output selection unit 320 and the USB control switching unit 330 in the signal source switching module 300 are composed of a plurality of signal converters. The display switching unit 310 corresponds to the display signal, the output selection unit 320 corresponds to the external output signal, and the USB control switching unit 330 corresponds to the control signal of the USB device 500.

[0032] As an example, converting the first display signal and the second display signal into preset format signals, and then determining the final display signal (output signal) from the first display signal and the second display signal can be specifically implemented by the display switching unit 310 .

[0033] Specifically, the display switching unit 310 includes a first signal converter 311 , a second signal converter 312 , a first signal selector 313 , and a signal selection processor 314 .

[0034] The first signal converter 311 is connected to the integrated graphics card 210 in the server main control module 200, and is used to convert the display DP signal into a second display HDMI signal; the second signal converter 312 is connected to the integrated graphics card 210, and is used to convert the external DP signal into a second external HDMI signal or a second external VGA signal; the first signal selector 313 is connected to the first signal converter 311 and the independent graphics card 220 in the server main control module 200, and is used to obtain the first display HDMI signal and the second display HDMI signal, obtain the selection instruction through the preset first selection key, and obtain the selected display HDMI signal; the signal selection processor 314 is connected to the external input and output module 100 and the first signal selector 313, and is used to obtain the selected display HDMI signal and the second display VGA signal, obtain the selection instruction through the preset second selection key, obtain the selected display signal, and convert the selected display signal into a display signal in LVDS format.

[0035] It should be noted that the first signal converter 311 and the second signal converter 312 can both be LT8712X converters; the first signal selector 313 can be a Longxun HDMI two-to-one signal selector; and the signal selection processor 314 can be a processor of model UTS6710. In addition, the above-mentioned obtaining the selection instruction by presetting the first selection key and obtaining the selection instruction by presetting the second selection key can be implemented by the existing technology, and this application will not be repeated here.

[0036] In addition, in order to adapt the display of the display signal in LVDS format, the system can also include a display screen signal converter 315, which is connected to the server LCD screen 400; it can convert the display signal in LVDS format into a display signal in EDP format, and then transmit it to the server LCD screen 400.

[0037] That is, the display screen signal converter 315 is a converter that converts LVDS signals into EDP signals.

[0038] As a second example, converting the first display signal and the second display signal into preset format signals, and then determining the final external output signal (output signal) from the first display signal and the second display signal can be specifically implemented by the output selection unit 320 .

[0039] Specifically, the output selection unit 320 includes a second signal selector 321 and a third signal selector 322; the external output signal includes at least an HDMI output signal and a VGA output signal.

[0040] Among them, the second signal selector 321 is connected to the independent graphics card 220 and the second signal converter 312, and is used to obtain the first external HDMI signal and the second external HDMI signal, and obtain the selection instruction through the preset third selection key to convert the external HDMI signal corresponding to the selection instruction into an HDMI output signal; the third signal selector 322 is connected to the independent graphics card 220 and the second signal converter 312, and is used to obtain the first external VGA signal and the second external VGA signal, and obtain the selection instruction through the preset fourth selection key to convert the external VGA signal corresponding to the selection instruction into a VGA output signal.

[0041] It should be noted that the second signal selector 321 can be a Longxun HDMI two-choice signal selector; the third signal selector 322 can be a VGA two-choice signal selector. In addition, the above-mentioned preset third selection key to obtain the selection instruction and the preset fourth selection key to obtain the selection instruction can be implemented by the existing technology, and this application will not be repeated here.

[0042] After obtaining the external output signal, the present application can send the external output signal to the corresponding external device. The specific scheme may be: The external input / output module 100 is also connected to an external device, and can send an external output signal to a corresponding external device based on the format of the external output signal.

[0043] More specifically, the external device includes at least an external HDMI processing device and a VGA processing device, and the format of the external output signal includes at least an HDMI output signal and a VGA output signal; the external input and output module 100 can output the HDMI output signal to the external HDMI processing device and output the VGA output signal to the external VGA processing device.

[0044] As a third example, determining the final control signal from the external control signal of the USB device and the internal control signal of the USB device can be specifically implemented by the USB control switching unit 330 .

[0045] Specifically, the USB control switching unit 330 includes a fourth signal selector 331; The fourth signal selector 331 is connected to the external input and output module 100 and the USB device 500, and is used to obtain the external control signal of the USB device and the internal control signal of the USB device, and obtain the selection instruction through the preset fifth selection key to output the USB device control signal corresponding to the selection instruction as the final control signal.

[0046] It should be noted that the fourth signal selector 331 can be a signal selector for selecting one of two USB device control signals. In addition, the present application can determine the specific number of the fourth signal selectors 331 according to the number of the involved USB devices 500. In addition, obtaining the selection instruction by presetting the fifth selection key can be implemented by the prior art, and the present application will not elaborate on it here.

[0047] In addition, the system also includes button indicator lights, and the button indicator lights at least include a power-on indicator light, a power indicator light, a hard disk indicator light, and a current signal source indicator light; The signal source indicator light is connected to the signal source switching module 300 and the server main control module 200 , and is used to obtain control instructions issued by the signal source switching module 300 or the server main control module 200 .

[0048] Based on the above description and Figure 2 As shown, those skilled in the art can understand that the present application proposes a server dual signal source switching display output system, which can perform dual signal source switching display of the display screen, output to external devices and control the USB device 500.

[0049] The dual signal source switching display of the display screen can be specifically as follows: An external signal is obtained through the external input and output module 100 (the external signal may be a first display signal and an external control signal of a USB device), and an internal signal is obtained through the server main control module 200 (a server main control signal, and the server main control signal includes a second display signal, an external output signal and an internal control signal of a USB device, and the integrated graphics card 210 is used to output a display DP signal or an external DP signal, and the independent graphics card 220 is used to output a first display HDMI signal, a first external HDMI signal or a first external VGA signal). Through the first signal converter 311, the display DP signal can be converted into a second display HDMI signal, and then through the first signal selector 313, the second display HDMI signal and the first display HDMI signal are obtained, and then a technician in this field can select a signal here to obtain a selected display HDMI signal; and then through the signal selection processor 314, the selected display HDMI signal and the external first display signal are obtained, and a technician in this field can select a signal here to obtain a selected signal and convert it into a display signal in LVDS format. In order to facilitate display on the server LCD screen 400, the display signal in LVDS format is converted into a display signal in EDP format through the display screen signal converter 315.

[0050] The output to the external device may specifically be: Through the second signal converter 312, the external DP signal can be converted into a second external HDMI signal or a second external VGA signal; through the second signal selector 321, the second external HDMI signal and the first external HDMI signal output by the independent graphics card 220 are obtained, and technical personnel in the field can select the signal here to obtain the HDMI output signal; through the third signal selector 322, the second external VGA signal and the first external VGA signal output by the independent graphics card 220 are obtained, and technical personnel in the field can select the signal here to obtain the VGA output signal; the external input and output module 100 obtains the HDMI output signal and the VGA output signal, and outputs them to the external device.

[0051] Among them, controlling the USB device 500 may specifically include: The fourth signal selector 331 obtains the external control signal of the USB device from the external input and output module and the internal control signal of the USB device from the server main control module 200. A person skilled in the art can select the signal here to obtain the final control signal and then output it to the USB device 500.

[0052] In addition, the embodiment of the present application also provides a server dual signal source switching display output method, such as Figure 2 As shown, the method provided in the embodiment of the present application mainly includes the following steps: Step 610: Obtain external signals through the external input and output module.

[0053] The external signal includes a first display signal of a KVM signal source and an external control signal of a USB device.

[0054] Step 620: Obtain a server main control signal through the server main control module.

[0055] The server main control signal includes a second display signal, an external output signal and an internal control signal of the USB device.

[0056] Step 630: Convert the first display signal and the second display signal into preset format signals through the signal source switching module, and then determine the final output signal from the first display signal and the second display signal; and determine the final control signal from the USB device external control signal and the USB device internal control signal.

[0057] Among them, the output signals are display signals and external output signals respectively.

[0058] Step 630: Send the external output signal to the corresponding external device through the external input and output module based on the format of the external output signal.

[0059] So far, the technical solutions of the present disclosure have been described in combination with the above multiple embodiments, but it is easy for those skilled in the art to understand that the protection scope of the present disclosure is not limited to these specific embodiments. Without departing from the technical principles of the present disclosure, those skilled in the art can split and combine the technical solutions in the above-mentioned various embodiments, and can also make equivalent changes or replacements to the relevant technical features. Any changes, equivalent replacements, improvements, etc. made within the technical concept and / or technical principle of the present disclosure will fall within the protection scope of the present disclosure.

Claims

1. A server dual signal source switching display output system, characterized in that: The system comprises: An external input and output module, used to obtain external signals; wherein the external signals include a first display signal of a KVM signal source and an external control signal of a USB device; The server main control module includes an integrated graphics card and an independent graphics card, and is used to output a server main control signal; wherein the server main control signal includes a second display signal, an external output signal, and a USB device internal control signal; The signal source switching module includes a display switching unit, an output selection unit and a USB control switching unit, and is connected to the external input and output module and the server main control module, and is used to convert the first display signal and the second display signal into a preset format signal, and then determine the final output signal from the first display signal and the second display signal; and determine the final control signal from the external control signal of the USB device and the internal control signal of the USB device; wherein the output signals are display signals and external output signals respectively; The external input and output module is connected to the external device and is also used to send the external output signal to the corresponding external device based on the format of the external output signal.

2. The server dual signal source switching display output system according to claim 1, characterized in that: The first display signal is an external VGA signal; The second display signal at least includes: a display DP signal, a first display HDMI signal and a USB device internal control signal; the external output signal at least includes: an external DP signal, a first external HDMI signal and a first external VGA signal.

3. The server dual signal source switching display output system according to claim 2, characterized in that: The integrated graphics card is used to output a display DP signal or an external DP signal, and the independent graphics card is used to output a first display HDMI signal, a first external HDMI signal or a first external VGA signal; wherein the USB device includes at least: a touch screen, a keyboard and a mouse.

4. The server dual signal source switching display output system according to claim 3, characterized in that: The display switching unit includes a first signal converter, a second signal converter, a first signal selector, and a signal selection processor; The first signal converter is connected to the integrated graphics card in the server main control module and is used to convert the display DP signal into the second display HDMI signal; A second signal converter, connected to the integrated graphics card, for converting the external DP signal into a second external HDMI signal or a second external VGA signal; A first signal selector is connected to the first signal converter and the independent graphics card in the server main control module, and is used to obtain the first display HDMI signal and the second display HDMI signal, obtain a selection instruction through a preset first selection key, and obtain a selected display HDMI signal; The signal selection processor is connected to the external input and output module and the first signal selector, and is used to obtain the selected display HDMI signal and the second display VGA signal, obtain the selection instruction through the preset second selection key, obtain the selected display signal, and convert the selected display signal into a display signal in LVDS format.

5. The server dual signal source switching display output system according to claim 4, characterized in that: The display switching unit includes a display screen signal converter, and the display screen signal converter is connected to the signal selection processor and the server LCD screen; Used to convert the display signal in LVDS format into the display signal in EDP format, and then transmit it to the server LCD screen.

6. The server dual signal source switching display output system according to claim 4, characterized in that: The output selection unit includes a second signal selector and a third signal selector; the external output signal includes at least an HDMI output signal and a VGA output signal; The second signal selector is connected to the independent graphics card and the second signal converter, and is used to obtain the first external HDMI signal and the second external HDMI signal, and obtain the selection instruction through the preset third selection key to convert the external HDMI signal corresponding to the selection instruction into an HDMI output signal; The third signal selector is connected to the independent graphics card and the second signal converter, and is used to obtain the first external VGA signal and the second external VGA signal, and obtain the selection instruction through the preset fourth selection key to convert the external VGA signal corresponding to the selection instruction into a VGA output signal.

7. The server dual signal source switching display output system according to claim 1 or 6, characterized in that: The external device at least includes an external HDMI processing device and a VGA processing device, and the format of the external output signal at least includes an HDMI output signal and a VGA output signal; The external input and output module is used to output the HDMI output signal to an external HDMI processing device and output the VGA output signal to an external VGA processing device.

8. The server dual signal source switching display output system according to claim 1, characterized in that: The USB control switching unit includes a fourth signal selector; The fourth signal selector is connected to the external input and output module and the USB device, and is used to obtain the external control signal of the USB device and the internal control signal of the USB device, and obtain the selection instruction through the preset fifth selection key to output the USB device control signal corresponding to the selection instruction as the final control signal.

9. The server dual signal source switching display output system according to claim 1, characterized in that: The system further includes a button indicator light, and the button indicator light at least includes a power-on indicator light, a power indicator light, a hard disk indicator light, and a current signal source indicator light; And the signal source indicator light is connected to the signal source switching module and the server main control module, and is used to obtain the control instructions sent by the signal source switching module or the server main control module.

10. A server dual signal source switching display output method, applied to the server dual signal source switching display output system according to claim 1, characterized in that: The method comprises: Obtaining external signals through the external input and output module; wherein the external signals include the first display signal of the KVM signal source and the external control signal of the USB device; Obtaining a server main control signal through a server main control module; wherein the server main control signal includes a second display signal, an external output signal, and an internal control signal of a USB device; The first display signal and the second display signal are converted into preset format signals through the signal source switching module, and then the final output signal is determined from the first display signal and the second display signal; and the final control signal is determined from the external control signal of the USB device and the internal control signal of the USB device; wherein the output signals are display signals and external output signals respectively; Through the external input and output module, the external output signal is sent to the corresponding external device based on the format of the external output signal.

Images