Abstract:
A KVM switch is provided for a set of user interface devices to share a plurality of computers. The KVM switch comprises a network port, a second interface, at least one first interface, a switch device and an Ethernet hub. The network port is arranged to connect to a network. The second interface is arranged to connect the set of user interface devices. The first interface is arranged to connect the computers, and the first interface has a port for connecting a network interface of the computers. The switch device is arranged to route paths between the second interface and the first interface. The Ethernet hub is arranged to connect the network port and the port of the first interface.

Description:
BACKGROUND  
       [0001]     1. Field of Invention  
         [0002]     The present invention relates to a KVM switch. More particularly, the present invention relates to a KVM switch having a network hub for supporting the over-IP process.  
         [0003]     2. Description of Related Art  
         [0004]     With the rapid development in information technology, computers and their peripherals have become very popular. Typically, each computer is equipped with one set of user interface devices, may including a keyboard, a mouse and a monitor. However, this equipment wastes money and occupies too much space if one has several computers. Therefore, a keyboard-video-mouse (KVM) switch is proposed to use at least one set of user interface devices to manage several computers and their peripherals. Using the KVM switch reduces hardware cost and decreases waste of space while simultaneously conquering the problem of compatibility between different interfaces.  
         [0005]     Traditionally, the KVM switch connects multiple computers and multiple sets of user interface devices through many combined cables. In addition, due to network applications have become commonplace in recent years, every computer may be configured with a network interface card connected to a separated Ethernet hub through an Ethernet cable (e.g. a CAT5 cable). When the KVM switch is used along with a network hub, their cables, i.e. the combined KVM cables and Ethernet cables, are crowded together.  
         [0006]     So many cables occupy much space and are not easy to put in order because the cables are different in shapes and lengths. Moreover, system administrators encounter difficulty in managing and checking the complicated cables, especially when changing, moving, maintaining or repairing the cables. In addition, costumers need to separately buy a network hub and a KVM switch to meet their sharing and networking requirements, which is very inconvenient and unnecessarily costly.  
       SUMMARY  
       [0007]     It is therefore an aspect of the present invention to provide a keyboard-video-mouse (KVM) switch, in which a network hub is integrated, to reduce the cost, reduce the occupied space and make managing the arrangement of cables easy for users.  
         [0008]     According to one preferred embodiment of the present invention, a KVM switch is provided for a set of user interface devices to share a plurality of computers. The KVM switch comprises a network port, a second interface, at least one first interface, a switch device and an Ethernet hub. The network port is arranged to connect to a network. The second interface is arranged to connect the set of user interface devices. The first interface is arranged to connect the computers, and the first interface has a port for connecting a network interface of the computers. The switch device is arranged to route paths between the second interface and the first interface. The Ethernet hub is arranged to connect the network port and the port of the first interface.  
         [0009]     It is another aspect of the present invention to provide a KVM switch, which supports the over-IP process by an integrated network hub, for facilitating the transmission of over-IP data.  
         [0010]     According to another preferred embodiment of the present invention, a KVM switch is provided for a set of user interface devices to share a plurality of computers. The KVM switch comprises at plurality of first interfaces, a second interface, a network port, a plurality of ports, an Ethernet controller, an Ethernet hub and a switch device.  
         [0011]     The first interfaces are arranged to connect the computers, and the second interface is arranged to connect the set of user interface devices. The network port is arranged to connect to a network and to receive or transmit over-IP data of an over-IP process. The ports are arranged to connect network interfaces of the computers. The Ethernet controller is used for providing an MAC for the over-IP process, and the Ethernet hub is arranged to connect the network port, the Ethernet controller and the ports. The switch device is arranged to route paths between the second interface and the first interfaces, and the switch device is electrically connected to the Ethernet hub through the Ethernet controller for routing the over-IP data among the second interface, the first interfaces and the network port.  
         [0012]     It is to be understood that both the foregoing general description and the following detailed description are examples and are intended to provide further explanation of the invention as claimed.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:  
         [0014]      FIG. 1  is a schematic view of the external connection of one preferred embodiment of the present invention;  
         [0015]      FIGS. 2A and 2B  illustrate schematic views of two preferred embodiments of the present invention;  
         [0016]      FIG. 3  is a schematic view of the interior of a KVM of one preferred embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.  
         [0018]     The present invention integrates a network hub into a KVM switch, and further designs the KVM switch to support an over-IP process. Therefore, the KVM switch of the present invention is cheaper, lighter and more convenient for users than conventional arrangements.  
         [0019]      FIG. 1  is a schematic view of the external connection of one preferred embodiment of the present invention for illustrating the connections among a network, a plurality of computers  112  and plural sets of user interface devices  114  through a KVM switch  100 . As illustrated in  FIG. 1 , a first interface  102  is arranged to connect the computers  112 , and a second interface  104  is arranged to connect the sets of user interface devices  114 . Moreover, the KVM switch  100  connects the computers  112  and the sets of user interface devices  114  to the network  116  through a network port  106 , e.g. an uplink port.  
         [0020]     The computers  112  can be servers, personal computers, notebooks or other computing devices having video output functions. One of the sets of user interface devices  114  includes manipulating devices (such as a keyboard and a mouse) and a display device (such as a CRT display or a LCD display). The network  116  can be a local area network (LAN), a wireless area network (WAN) or other communication networks.  
         [0021]      FIGS. 2A and 2B  illustrate schematic views of two preferred embodiments of the present invention for interpreting two types of the system architecture of the KVM switch  100 . The differences between the two types of the system architecture include the first interfaces and the cables for connecting the KVM switch and the computers. For clarity, only one set of user interface devices  114  and four computers  112  are illustrated in  FIGS. 2A and 2B . The set of user interface devices  114  includes a mouse  214   a , a display  214   b  and a keyboard  214   c , each of which is separately connected to its corresponding connector of a second interface  204  of a KVM switch  200   a.    
         [0022]     In a first type of the system architecture, illustrated in  FIG. 2A , each of first interfaces  202   a  of the KVM switch  200   a  includes a set of connectors  212  for connecting mouse, video and keyboard connectors of a computer  112 , in addition to including a port  216  for connecting a network interface of the computer  112 . According to another preferred embodiment of the present invention, the set of connectors  212  and the port  216  can be combined, and therefore a combined cable  222   a , which is used to transmit an Ethernet signals for network connection and keyboard/video/mouse signals bound together, is easily provided to connect the first interface  202   a  of the KVM switch  200   a  to one of the computers  112 , especially in this first type of system architecture.  
         [0023]     That is, due to the possible and simple combination of the Ethernet signal and the keyboard/video/mouse signals, the first type of system architecture can decrease the occupied space, enabling users to easily manage the arrangement of those cables.  
         [0024]     In a second type of the system architecture, illustrated in  FIG. 2B , each of first interfaces  202   b  of the KVM switch  200   b  includes plural sets of connectors  212  for connecting mouse, video and keyboard connectors of computers  112 . The KVM switch  200   b  further has a plurality of ports  216  arranged to connect network interfaces of the computers  112 . The set of connectors  212  and the port  216  are not adjacent to each other, and therefore an Ethernet cable  222   c  (such as a CAT5 cable) and a keyboard/video/mouse cable  222   b  are separately used to connect the network interface and the mouse, video and keyboard connectors of one of the computers  112 .  
         [0025]     That is, due to the separate cables of different functions, the second type of system architecture can be used more flexibly and conveniently for users to configure them in different locations and conditions. Moreover, the Ethernet cable and the keyboard/video/mouse cable are common and widely used in computer applications, and users thus can easily obtain and install them without any special order and attention.  
         [0026]      FIG. 3  is a schematic view of an interior of a KVM  300  of one preferred embodiment of the present invention, such as the KVM switch  200   a  or  200   b  in  FIG. 2A  or  2 B. As shown in  FIG. 3 , an embedded micro-processor (MCP)  304  is used to handle the whole system&#39;s function of the KVM  300 . An FPGA or ASIC  302  is used to handle keyboard and mouse signals between the computers connected to the sets of connectors  212  (P 1 ˜P 4 ) and the sets of user interface devices connected to the second interface  204 .  
         [0027]     A video switch circuit  306  is arranged to provide a switch control to let one of the server&#39;s video signals to pass through. Moreover, the switch control is implemented by a high-speed MUX/DEMUX analog switch chip if the video signals are analog, for example. A video operational amplifier and/or video buffer  312  is provided between the video switch circuit  306  and the video connector (V) of the second interface  204 , for enhancing the video signals and implementing the video gains. In other words, the switch device of the preferred embodiment includes the foregoing FPGA or ASIC  302 , embedded micro-processor  304  and video switch  306 .  
         [0028]     Because an Ethernet hub  308  is integrated into the KVM switch  300  of the preferred embodiment, an over-IP process is therefore more easily implemented and obtains a good performance from this integration. The following descriptions use an example, which involves the video signals that are more complicated than the simple electrical signals, to illustrate the over-IP process performed by the KVM switch  300  of the preferred embodiment.  
         [0029]     First, an Ethernet hub  308  is provided, which includes a main Ethernet-hub chip and further a LAN filter circuit. The Ethernet hub  308  is arranged to connect the network (e.g. the LAN or WAN) and the network interfaces of the computers through the network port  206  and the ports  216 , respectively.  
         [0030]     When the over-IP process is performed, over-IP data (e.g. video signals) is transmitted from a local computer (such as the computer connected to one of the sets of connectors  212 ) to one set of remote user interface devices, for example. First, the video signals pass through the video operational amplifier and/or video buffer  312  and the video switch circuit  306 . A video operational amplifier and/or video buffer  318  is provided between the FPGA or ASIC  302  and a video analog-to-digital converter  316 , for enhancing the video signals and implementing the video gains.  
         [0031]     A video analog-to-digital converter (ADC)  316  is electrically connected to the video operational amplifier and/or video buffer  318  to provide an analog interface optimized for capturing RGB graphics signals from computers and outputting digital pixel signals. The FPGA or ASIC  302  of the preferred embodiment is arranged to handle image compression of video signals and the video sampling from the video ADC  316 . In order to process the video signals of the over-IP process, a DRAM memory  314  is electrically connected to the FPGA or ASIC  302  to provide the storage of video signals and compressed data.  
         [0032]     Then, the over-IP data, i.e. the converted foregoing video signals, is then transmitted from the FPGA or ASIC  302  to the Ethernet hub  308  through the embedded micro-processor  304 . A DRAM memory  326  is electrically connected to the embedded micro-processor  304  and is arranged to store temp data and stack data of the over-IP process. A FLASH memory  324  is electrically connected to the embedded micro-processor  304  and is used to provide the storage of the over-IP process KVM.  
         [0033]     After that, an Ethernet controller  322 , such as a highly integrated Fast Ethernet controller which has full compliance with IEEE 802.3u 100Base-T specifications and IEEE 802.3x Full Duplex Flow Control, is connected to and used to provide an MAC of the KVM switch  300  to the Ethernet hub  308 . The over-IP data, i.e. the video signals and remote keyboard/mouse data, is then transmitted to the network by the Ethernet hub  308 . In addition, a LAN filter may be further used for the Ethernet controller  322 . However, if the embedded micro-processor  304  is a SOC embedded Fast Ethernet controller, the Ethernet controller  322  can be omitted, but an additional Ethernet transceiver is still necessary.  
         [0034]     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.